nat: static mappings in flow hash

Put static mappings in flow hash, drop existing hash tables used for
static mappings. Drop refcount variables and use hash table as a single
point of truth. Allow creating a static mapping conflicting with dynamic
mapping, which will take precedence after dynamic mapping is freed, so
that the existing flow can finish transferring data.

Type: fix
Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: Ieeba691d83a83887d0a0baccd5f3832f66126096

31 files changed, 1298 insertions, 1468 deletions

diff --git a/src/plugins/nat/det44/det44.h b/src/plugins/nat/det44/det44.h
index 02b0fa7e81d..20dc8b1aec9 100644
--- a/src/plugins/nat/det44/det44.h
+++ b/src/plugins/nat/det44/det44.h
@@ -40,6 +40,7 @@
 #include <nat/lib/lib.h>
 #include <nat/lib/inlines.h>
 #include <nat/lib/ipfix_logging.h>
+#include <nat/lib/nat_proto.h>
 
 /* Session state */
 #define foreach_det44_session_state        \
diff --git a/src/plugins/nat/lib/alloc.h b/src/plugins/nat/lib/alloc.h
index a9a2c15fedc..0c302bf4cfb 100644
--- a/src/plugins/nat/lib/alloc.h
+++ b/src/plugins/nat/lib/alloc.h
@@ -21,6 +21,7 @@
 #define included_nat_lib_alloc_h__
 
 #include <vnet/ip/ip.h>
+#include <nat/lib/nat_proto.h>
 
 typedef struct nat_ip4_pool_addr_s nat_ip4_pool_addr_t;
 typedef struct nat_ip4_addr_port_s nat_ip4_addr_port_t;
diff --git a/src/plugins/nat/lib/inlines.h b/src/plugins/nat/lib/inlines.h
index fe1f7dd27bc..46be64d36cf 100644
--- a/src/plugins/nat/lib/inlines.h
+++ b/src/plugins/nat/lib/inlines.h
@@ -20,37 +20,6 @@
 
 #include <vnet/ip/icmp46_packet.h>
 
-always_inline nat_protocol_t
-ip_proto_to_nat_proto (u8 ip_proto)
-{
-  static const nat_protocol_t lookup_table[256] = {
-    [IP_PROTOCOL_TCP] = NAT_PROTOCOL_TCP,
-    [IP_PROTOCOL_UDP] = NAT_PROTOCOL_UDP,
-    [IP_PROTOCOL_ICMP] = NAT_PROTOCOL_ICMP,
-    [IP_PROTOCOL_ICMP6] = NAT_PROTOCOL_ICMP,
-  };
-
-  return lookup_table[ip_proto];
-}
-
-static_always_inline u8
-nat_proto_to_ip_proto (nat_protocol_t nat_proto)
-{
-  ASSERT (nat_proto <= NAT_PROTOCOL_ICMP);
-
-  static const u8 lookup_table[256] = {
-    [NAT_PROTOCOL_OTHER] = ~0,
-    [NAT_PROTOCOL_TCP] = IP_PROTOCOL_TCP,
-    [NAT_PROTOCOL_UDP] = IP_PROTOCOL_UDP,
-    [NAT_PROTOCOL_ICMP] = IP_PROTOCOL_ICMP,
-  };
-
-  ASSERT (NAT_PROTOCOL_OTHER == nat_proto || NAT_PROTOCOL_TCP == nat_proto
-	  || NAT_PROTOCOL_UDP == nat_proto || NAT_PROTOCOL_ICMP == nat_proto);
-
-  return lookup_table[nat_proto];
-}
-
 static_always_inline u8
 icmp_type_is_error_message (u8 icmp_type)
 {
diff --git a/src/plugins/nat/lib/ipfix_logging.c b/src/plugins/nat/lib/ipfix_logging.c
index 6e5e4b6c750..27a0b92ae71 100644
--- a/src/plugins/nat/lib/ipfix_logging.c
+++ b/src/plugins/nat/lib/ipfix_logging.c
@@ -51,7 +51,7 @@ typedef struct
   u8 nat_event;
   u32 src_ip;
   u32 nat_src_ip;
-  nat_protocol_t nat_proto;
+  ip_protocol_t proto;
   u16 src_port;
   u16 nat_src_port;
   u32 vrf_id;
@@ -577,9 +577,8 @@ nat_ipfix_send (flow_report_main_t *frm, vlib_frame_t *f, vlib_buffer_t *b0,
 
 static void
 nat_ipfix_logging_nat44_ses (u32 thread_index, u8 nat_event, u32 src_ip,
-                              u32 nat_src_ip, nat_protocol_t nat_proto,
-                              u16 src_port, u16 nat_src_port, u32 fib_index,
-                              int do_flush)
+			     u32 nat_src_ip, ip_protocol_t proto, u16 src_port,
+			     u16 nat_src_port, u32 fib_index, int do_flush)
 {
   nat_ipfix_logging_main_t *silm = &nat_ipfix_logging_main;
   nat_ipfix_per_thread_data_t *sitd = &silm->per_thread_data[thread_index];
@@ -590,12 +589,9 @@ nat_ipfix_logging_nat44_ses (u32 thread_index, u8 nat_event, u32 src_ip,
   u32 offset;
   vlib_main_t *vm = vlib_get_main ();
   u64 now;
-  u8 proto;
   u16 template_id;
   u32 vrf_id;
 
-  proto = nat_proto_to_ip_proto (nat_proto);
-
   now = (u64) ((vlib_time_now (vm) - silm->vlib_time_0) * 1e3);
   now += silm->milisecond_time_0;
 
@@ -1307,54 +1303,34 @@ nat_ipfix_flush_from_main (void)
 
 /**
  * @brief Generate NAT44 session create event
- *
- * @param thread_index thread index
- * @param src_ip       source IPv4 address
- * @param nat_src_ip   transaltes source IPv4 address
- * @param nat_proto   NAT transport protocol
- * @param src_port     source port
- * @param nat_src_port translated source port
- * @param vrf_id       VRF ID
  */
 void
-nat_ipfix_logging_nat44_ses_create (u32 thread_index,
-                                     u32 src_ip,
-				     u32 nat_src_ip,
-				     nat_protocol_t nat_proto,
-				     u16 src_port,
-				     u16 nat_src_port, u32 fib_index)
+nat_ipfix_logging_nat44_ses_create (u32 thread_index, u32 src_ip,
+				    u32 nat_src_ip, ip_protocol_t proto,
+				    u16 src_port, u16 nat_src_port,
+				    u32 fib_index)
 {
   skip_if_disabled ();
 
   nat_ipfix_logging_nat44_ses (thread_index, NAT44_SESSION_CREATE, src_ip,
-                                nat_src_ip, nat_proto, src_port, nat_src_port,
-				fib_index, 0);
+			       nat_src_ip, proto, src_port, nat_src_port,
+			       fib_index, 0);
 }
 
 /**
  * @brief Generate NAT44 session delete event
- *
- * @param thread_index thread index
- * @param src_ip       source IPv4 address
- * @param nat_src_ip   transaltes source IPv4 address
- * @param nat_proto   NAT transport protocol
- * @param src_port     source port
- * @param nat_src_port translated source port
- * @param vrf_id       VRF ID
  */
 void
-nat_ipfix_logging_nat44_ses_delete (u32 thread_index,
-                                     u32 src_ip,
-				     u32 nat_src_ip,
-				     nat_protocol_t nat_proto,
-				     u16 src_port,
-				     u16 nat_src_port, u32 fib_index)
+nat_ipfix_logging_nat44_ses_delete (u32 thread_index, u32 src_ip,
+				    u32 nat_src_ip, ip_protocol_t proto,
+				    u16 src_port, u16 nat_src_port,
+				    u32 fib_index)
 {
   skip_if_disabled ();
 
   nat_ipfix_logging_nat44_ses (thread_index, NAT44_SESSION_DELETE, src_ip,
-                                nat_src_ip, nat_proto, src_port, nat_src_port,
-				fib_index, 0);
+			       nat_src_ip, proto, src_port, nat_src_port,
+			       fib_index, 0);
 }
 
 /**
diff --git a/src/plugins/nat/lib/ipfix_logging.h b/src/plugins/nat/lib/ipfix_logging.h
index 0b2357a2604..0b8f568e1b1 100644
--- a/src/plugins/nat/lib/ipfix_logging.h
+++ b/src/plugins/nat/lib/ipfix_logging.h
@@ -117,15 +117,13 @@ int nat_ipfix_logging_enabled ();
 void nat_ipfix_logging_init (vlib_main_t * vm);
 int nat_ipfix_logging_enable_disable (int enable, u32 domain_id, u16 src_port);
 void nat_ipfix_logging_nat44_ses_create (u32 thread_index, u32 src_ip,
-                                          u32 nat_src_ip,
-                                          nat_protocol_t nat_proto,
-                                          u16 src_port, u16 nat_src_port,
-                                          u32 fib_index);
+					 u32 nat_src_ip, ip_protocol_t proto,
+					 u16 src_port, u16 nat_src_port,
+					 u32 fib_index);
 void nat_ipfix_logging_nat44_ses_delete (u32 thread_index, u32 src_ip,
-                                          u32 nat_src_ip,
-                                          nat_protocol_t nat_proto,
-                                          u16 src_port, u16 nat_src_port,
-                                          u32 fib_index);
+					 u32 nat_src_ip, ip_protocol_t proto,
+					 u16 src_port, u16 nat_src_port,
+					 u32 fib_index);
 void nat_ipfix_logging_addresses_exhausted(u32 thread_index, u32 pool_id);
 void nat_ipfix_logging_max_entries_per_user(u32 thread_index,
                                              u32 limit, u32 src_ip);
diff --git a/src/plugins/nat/lib/lib.c b/src/plugins/nat/lib/lib.c
index d2def2cc480..30bafac73c0 100644
--- a/src/plugins/nat/lib/lib.c
+++ b/src/plugins/nat/lib/lib.c
@@ -14,6 +14,7 @@
  */
 
 #include <nat/lib/lib.h>
+#include <nat/lib/nat_proto.h>
 
 uword
 unformat_nat_protocol (unformat_input_t *input, va_list *args)
diff --git a/src/plugins/nat/lib/lib.h b/src/plugins/nat/lib/lib.h
index b0b5229b337..cea9ed71c8c 100644
--- a/src/plugins/nat/lib/lib.h
+++ b/src/plugins/nat/lib/lib.h
@@ -54,19 +54,6 @@ typedef enum
 #undef _
 } nat_error_t;
 
-#define foreach_nat_protocol   \
-  _ (OTHER, 0, other, "other") \
-  _ (UDP, 1, udp, "udp")       \
-  _ (TCP, 2, tcp, "tcp")       \
-  _ (ICMP, 3, icmp, "icmp")
-
-typedef enum
-{
-#define _(N, i, n, s) NAT_PROTOCOL_##N = i,
-  foreach_nat_protocol
-#undef _
-} nat_protocol_t;
-
 /* default protocol timeouts */
 #define NAT_UDP_TIMEOUT 300
 #define NAT_TCP_TRANSITORY_TIMEOUT 240
@@ -96,29 +83,6 @@ nat_reset_timeouts (nat_timeouts_t * timeouts)
 }
 
 static_always_inline u32
-nat_session_get_timeout (nat_timeouts_t *timeouts, nat_protocol_t proto,
-			 u8 state)
-{
-  switch (proto)
-    {
-    case NAT_PROTOCOL_ICMP:
-      return timeouts->icmp;
-    case NAT_PROTOCOL_UDP:
-      return timeouts->udp;
-    case NAT_PROTOCOL_TCP:
-      {
-	if (state)
-	  return timeouts->tcp.transitory;
-	else
-	  return timeouts->tcp.established;
-      }
-    default:
-      return timeouts->udp;
-    }
-  return 0;
-}
-
-static_always_inline u32
 nat_calc_bihash_buckets (u32 n_elts)
 {
   n_elts = n_elts / 2.5;
@@ -138,10 +102,6 @@ nat_calc_bihash_buckets (u32 n_elts)
   return lower_pow2;
 }
 
-u8 *format_nat_protocol (u8 *s, va_list *args);
-
-uword unformat_nat_protocol (unformat_input_t *input, va_list *args);
-
 #endif /* included_nat_lib_h__ */
 /*
  * fd.io coding-style-patch-verification: ON
diff --git a/src/plugins/nat/lib/nat_proto.h b/src/plugins/nat/lib/nat_proto.h
new file mode 100644
index 00000000000..9b20d9a71d1
--- /dev/null
+++ b/src/plugins/nat/lib/nat_proto.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2021 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_nat_proto_h__
+#define included_nat_proto_h__
+
+#include <vnet/ip/ip.h>
+
+#define foreach_nat_protocol                                                  \
+  _ (OTHER, 0, other, "other")                                                \
+  _ (UDP, 1, udp, "udp")                                                      \
+  _ (TCP, 2, tcp, "tcp")                                                      \
+  _ (ICMP, 3, icmp, "icmp")
+
+typedef enum
+{
+#define _(N, i, n, s) NAT_PROTOCOL_##N = i,
+  foreach_nat_protocol
+#undef _
+} nat_protocol_t;
+
+always_inline nat_protocol_t
+ip_proto_to_nat_proto (ip_protocol_t ip_proto)
+{
+  static const nat_protocol_t lookup_table[256] = {
+    [IP_PROTOCOL_TCP] = NAT_PROTOCOL_TCP,
+    [IP_PROTOCOL_UDP] = NAT_PROTOCOL_UDP,
+    [IP_PROTOCOL_ICMP] = NAT_PROTOCOL_ICMP,
+    [IP_PROTOCOL_ICMP6] = NAT_PROTOCOL_ICMP,
+  };
+
+  return lookup_table[ip_proto];
+}
+
+static_always_inline ip_protocol_t
+nat_proto_to_ip_proto (nat_protocol_t nat_proto)
+{
+  ASSERT (nat_proto <= NAT_PROTOCOL_ICMP);
+
+  static const u8 lookup_table[256] = {
+    [NAT_PROTOCOL_OTHER] = ~0,
+    [NAT_PROTOCOL_TCP] = IP_PROTOCOL_TCP,
+    [NAT_PROTOCOL_UDP] = IP_PROTOCOL_UDP,
+    [NAT_PROTOCOL_ICMP] = IP_PROTOCOL_ICMP,
+  };
+
+  ASSERT (NAT_PROTOCOL_OTHER == nat_proto || NAT_PROTOCOL_TCP == nat_proto ||
+	  NAT_PROTOCOL_UDP == nat_proto || NAT_PROTOCOL_ICMP == nat_proto);
+
+  return lookup_table[nat_proto];
+}
+
+u8 *format_nat_protocol (u8 *s, va_list *args);
+
+uword unformat_nat_protocol (unformat_input_t *input, va_list *args);
+
+#endif /* included_nat_proto_h__ */
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/nat/lib/nat_syslog.c b/src/plugins/nat/lib/nat_syslog.c
index 2c395bf7fd8..98777ebf280 100644
--- a/src/plugins/nat/lib/nat_syslog.c
+++ b/src/plugins/nat/lib/nat_syslog.c
@@ -23,38 +23,7 @@
 #include <nat/lib/nat_syslog.h>
 #include <nat/lib/inlines.h>
 
-#define NAT_FACILITY SYSLOG_FACILITY_LOCAL0
-
-#define NAT_APPNAME "NAT"
-
-#define SADD_SDEL_SEVERITY SYSLOG_SEVERITY_INFORMATIONAL
-#define APMADD_APMDEL_SEVERITY SYSLOG_SEVERITY_INFORMATIONAL
-
-#define SADD_MSGID "SADD"
-#define SDEL_MSGID "SDEL"
-#define APMADD_MSGID "APMADD"
-#define APMDEL_MSGID "APMDEL"
-
-#define NSESS_SDID "nsess"
-#define NAPMAP_SDID "napmap"
-
-#define SSUBIX_SDPARAM_NAME "SSUBIX"
-#define SVLAN_SDPARAM_NAME "SVLAN"
-#define IATYP_SDPARAM_NAME "IATYP"
-#define ISADDR_SDPARAM_NAME "ISADDR"
-#define ISPORT_SDPARAM_NAME "ISPORT"
-#define IDADDR_SDPARAM_NAME "IDADDR"
-#define IDPORT_SDPARAM_NAME "IDPORT"
-#define XATYP_SDPARAM_NAME "XATYP"
-#define XSADDR_SDPARAM_NAME "XSADDR"
-#define XSPORT_SDPARAM_NAME "XSPORT"
-#define XDADDR_SDPARAM_NAME "XDADDR"
-#define XDPORT_SDPARAM_NAME "XDPORT"
-#define PROTO_SDPARAM_NAME "PROTO"
-#define SV6ENC_SDPARAM_NAME "SV6ENC"
-
-#define IATYP_IPV4 "IPv4"
-#define IATYP_IPV6 "IPv6"
+#include <nat/lib/nat_syslog_constants.h>
 
 static inline void
 nat_syslog_nat44_apmap (u32 ssubix, u32 sfibix, ip4_address_t * isaddr,
@@ -142,82 +111,6 @@ nat_syslog_dslite_apmdel (u32 ssubix, ip6_address_t * sv6enc,
 }
 
 static inline void
-nat_syslog_nat44_sess (u32 ssubix, u32 sfibix, ip4_address_t * isaddr,
-		       u16 isport, ip4_address_t * xsaddr, u16 xsport,
-		       ip4_address_t * idaddr, u16 idport,
-		       ip4_address_t * xdaddr, u16 xdport,
-		       nat_protocol_t proto, u8 is_add, u8 is_twicenat)
-{
-  syslog_msg_t syslog_msg;
-  fib_table_t *fib;
-
-  if (!syslog_is_enabled ())
-    return;
-
-  if (syslog_severity_filter_block (SADD_SDEL_SEVERITY))
-    return;
-
-  fib = fib_table_get (sfibix, FIB_PROTOCOL_IP4);
-
-  syslog_msg_init (&syslog_msg, NAT_FACILITY, SADD_SDEL_SEVERITY, NAT_APPNAME,
-		   is_add ? SADD_MSGID : SDEL_MSGID);
-
-  syslog_msg_sd_init (&syslog_msg, NSESS_SDID);
-  syslog_msg_add_sd_param (&syslog_msg, SSUBIX_SDPARAM_NAME, "%d", ssubix);
-  syslog_msg_add_sd_param (&syslog_msg, SVLAN_SDPARAM_NAME, "%d",
-			   fib->ft_table_id);
-  syslog_msg_add_sd_param (&syslog_msg, IATYP_SDPARAM_NAME, IATYP_IPV4);
-  syslog_msg_add_sd_param (&syslog_msg, ISADDR_SDPARAM_NAME, "%U",
-			   format_ip4_address, isaddr);
-  syslog_msg_add_sd_param (&syslog_msg, ISPORT_SDPARAM_NAME, "%d",
-			   clib_net_to_host_u16 (isport));
-  syslog_msg_add_sd_param (&syslog_msg, XATYP_SDPARAM_NAME, IATYP_IPV4);
-  syslog_msg_add_sd_param (&syslog_msg, XSADDR_SDPARAM_NAME, "%U",
-			   format_ip4_address, xsaddr);
-  syslog_msg_add_sd_param (&syslog_msg, XSPORT_SDPARAM_NAME, "%d",
-			   clib_net_to_host_u16 (xsport));
-  syslog_msg_add_sd_param (&syslog_msg, PROTO_SDPARAM_NAME, "%d",
-			   nat_proto_to_ip_proto (proto));
-  syslog_msg_add_sd_param (&syslog_msg, XDADDR_SDPARAM_NAME, "%U",
-			   format_ip4_address, xdaddr);
-  syslog_msg_add_sd_param (&syslog_msg, XDPORT_SDPARAM_NAME, "%d",
-			   clib_net_to_host_u16 (xdport));
-  if (is_twicenat)
-    {
-      syslog_msg_add_sd_param (&syslog_msg, IDADDR_SDPARAM_NAME, "%U",
-			       format_ip4_address, idaddr);
-      syslog_msg_add_sd_param (&syslog_msg, IDPORT_SDPARAM_NAME, "%d",
-			       clib_net_to_host_u16 (idport));
-    }
-
-  syslog_msg_send (&syslog_msg);
-}
-
-void
-nat_syslog_nat44_sadd (u32 ssubix, u32 sfibix, ip4_address_t * isaddr,
-		       u16 isport, ip4_address_t * idaddr, u16 idport,
-		       ip4_address_t * xsaddr, u16 xsport,
-		       ip4_address_t * xdaddr, u16 xdport,
-		       nat_protocol_t proto, u8 is_twicenat)
-{
-  nat_syslog_nat44_sess (ssubix, sfibix, isaddr, isport, xsaddr, xsport,
-			 idaddr, idport, xdaddr, xdport, proto, 1,
-			 is_twicenat);
-}
-
-void
-nat_syslog_nat44_sdel (u32 ssubix, u32 sfibix, ip4_address_t * isaddr,
-		       u16 isport, ip4_address_t * idaddr, u16 idport,
-		       ip4_address_t * xsaddr, u16 xsport,
-		       ip4_address_t * xdaddr, u16 xdport,
-		       nat_protocol_t proto, u8 is_twicenat)
-{
-  nat_syslog_nat44_sess (ssubix, sfibix, isaddr, isport, xsaddr, xsport,
-			 idaddr, idport, xdaddr, xdport, proto, 0,
-			 is_twicenat);
-}
-
-static inline void
 nat_syslog_nat64_sess (u32 sfibix, ip6_address_t * isaddr, u16 isport,
 		       ip4_address_t * xsaddr, u16 xsport,
 		       ip4_address_t * xdaddr, u16 xdport,
diff --git a/src/plugins/nat/lib/nat_syslog.h b/src/plugins/nat/lib/nat_syslog.h
index 9721664cf54..f929bf310b4 100644
--- a/src/plugins/nat/lib/nat_syslog.h
+++ b/src/plugins/nat/lib/nat_syslog.h
@@ -20,6 +20,7 @@
 #define __included_nat_syslog_h__
 
 #include <nat/lib/lib.h>
+#include <nat/lib/nat_proto.h>
 
 void nat_syslog_nat44_apmadd (u32 ssubix, u32 sfibix, ip4_address_t * isaddr,
 			      u16 isport, ip4_address_t * xsaddr, u16 xsport,
@@ -41,18 +42,6 @@ nat_syslog_dslite_apmdel (u32 ssubix, ip6_address_t * sv6enc,
 			  ip4_address_t * xsaddr, u16 xsport,
 			  nat_protocol_t proto);
 
-void nat_syslog_nat44_sadd (u32 ssubix, u32 sfibix, ip4_address_t * isaddr,
-			    u16 isport, ip4_address_t * idaddr, u16 idport,
-			    ip4_address_t * xsaddr, u16 xsport,
-			    ip4_address_t * xdaddr, u16 xdport,
-			    nat_protocol_t proto, u8 is_twicenat);
-
-void nat_syslog_nat44_sdel (u32 ssubix, u32 sfibix, ip4_address_t * isaddr,
-			    u16 isport, ip4_address_t * idaddr, u16 idport,
-			    ip4_address_t * xsaddr, u16 xsport,
-			    ip4_address_t * xdaddr, u16 xdport,
-			    nat_protocol_t proto, u8 is_twicenat);
-
 void nat_syslog_nat64_sadd (u32 sfibix, ip6_address_t * isaddr, u16 isport,
 			    ip4_address_t * xsaddr, u16 xsport,
 			    ip4_address_t * xdaddr, u16 xdport,
diff --git a/src/plugins/nat/lib/nat_syslog_constants.h b/src/plugins/nat/lib/nat_syslog_constants.h
new file mode 100644
index 00000000000..eeea7d2654e
--- /dev/null
+++ b/src/plugins/nat/lib/nat_syslog_constants.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2021 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @file
+ * @brief NAT syslog logging constants
+ */
+#ifndef __included_nat_syslog_constants_h__
+#define __included_nat_syslog_constants_h__
+
+#define NAT_FACILITY SYSLOG_FACILITY_LOCAL0
+
+#define NAT_APPNAME "NAT"
+
+#define SADD_SDEL_SEVERITY     SYSLOG_SEVERITY_INFORMATIONAL
+#define APMADD_APMDEL_SEVERITY SYSLOG_SEVERITY_INFORMATIONAL
+
+#define SADD_MSGID   "SADD"
+#define SDEL_MSGID   "SDEL"
+#define APMADD_MSGID "APMADD"
+#define APMDEL_MSGID "APMDEL"
+
+#define NSESS_SDID  "nsess"
+#define NAPMAP_SDID "napmap"
+
+#define SSUBIX_SDPARAM_NAME "SSUBIX"
+#define SVLAN_SDPARAM_NAME  "SVLAN"
+#define IATYP_SDPARAM_NAME  "IATYP"
+#define ISADDR_SDPARAM_NAME "ISADDR"
+#define ISPORT_SDPARAM_NAME "ISPORT"
+#define IDADDR_SDPARAM_NAME "IDADDR"
+#define IDPORT_SDPARAM_NAME "IDPORT"
+#define XATYP_SDPARAM_NAME  "XATYP"
+#define XSADDR_SDPARAM_NAME "XSADDR"
+#define XSPORT_SDPARAM_NAME "XSPORT"
+#define XDADDR_SDPARAM_NAME "XDADDR"
+#define XDPORT_SDPARAM_NAME "XDPORT"
+#define PROTO_SDPARAM_NAME  "PROTO"
+#define SV6ENC_SDPARAM_NAME "SV6ENC"
+
+#define IATYP_IPV4 "IPv4"
+#define IATYP_IPV6 "IPv6"
+
+#endif /* __included_nat_syslog_constants_h__ */
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/nat/nat44-ed/nat44_ed.c b/src/plugins/nat/nat44-ed/nat44_ed.c
index a11043682b9..d639392019b 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed.c
@@ -28,9 +28,11 @@
 #include <vppinfra/bihash_16_8.h>
 
 #include <nat/lib/log.h>
-#include <nat/lib/nat_syslog.h>
 #include <nat/lib/nat_inlines.h>
 #include <nat/lib/ipfix_logging.h>
+#include <vnet/syslog/syslog.h>
+#include <nat/lib/nat_syslog_constants.h>
+#include <nat/lib/nat_syslog.h>
 
 #include <nat/nat44-ed/nat44_ed.h>
 #include <nat/nat44-ed/nat44_ed_affinity.h>
@@ -183,29 +185,6 @@ static void nat44_ed_db_free ();
 u32 nat_calc_bihash_buckets (u32 n_elts);
 
 u8 *
-format_session_kvp (u8 * s, va_list * args)
-{
-  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
-
-  s = format (s, "%U thread-index %llu session-index %llu", format_snat_key,
-	      v->key, nat_value_get_thread_index (v),
-	      nat_value_get_session_index (v));
-
-  return s;
-}
-
-u8 *
-format_static_mapping_kvp (u8 * s, va_list * args)
-{
-  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
-
-  s = format (s, "%U static-mapping-index %llu",
-	      format_snat_key, v->key, v->value);
-
-  return s;
-}
-
-u8 *
 format_ed_session_kvp (u8 * s, va_list * args)
 {
   clib_bihash_kv_16_8_t *v = va_arg (*args, clib_bihash_kv_16_8_t *);
@@ -227,59 +206,81 @@ format_ed_session_kvp (u8 * s, va_list * args)
   return s;
 }
 
-void
-nat_free_session_data (snat_main_t * sm, snat_session_t * s, u32 thread_index,
-		       u8 is_ha)
+static_always_inline int
+nat44_ed_sm_i2o_add (snat_main_t *sm, snat_static_mapping_t *m,
+		     ip4_address_t addr, u16 port, u32 fib_index, u8 proto)
 {
-      per_vrf_sessions_unregister_session (s, thread_index);
+  ASSERT (!pool_is_free (sm->static_mappings, m));
+  clib_bihash_kv_16_8_t kv;
+  nat44_ed_sm_init_i2o_kv (&kv, addr.as_u32, port, fib_index, proto,
+			   m - sm->static_mappings);
+  return clib_bihash_add_del_16_8 (&sm->flow_hash, &kv, 1 /*is_add*/);
+}
 
-      if (nat_ed_ses_i2o_flow_hash_add_del (sm, thread_index, s, 0))
-	nat_elog_warn (sm, "flow hash del failed");
+static_always_inline int
+nat44_ed_sm_i2o_del (snat_main_t *sm, ip4_address_t addr, u16 port,
+		     u32 fib_index, u8 proto)
+{
+  clib_bihash_kv_16_8_t kv;
+  nat44_ed_sm_init_i2o_k (&kv, addr.as_u32, port, fib_index, proto);
+  return clib_bihash_add_del_16_8 (&sm->flow_hash, &kv, 0 /*is_add*/);
+}
 
-      if (nat_ed_ses_o2i_flow_hash_add_del (sm, thread_index, s, 0))
-	nat_elog_warn (sm, "flow hash del failed");
+static_always_inline int
+nat44_ed_sm_o2i_add (snat_main_t *sm, snat_static_mapping_t *m,
+		     ip4_address_t addr, u16 port, u32 fib_index, u8 proto)
+{
+  ASSERT (!pool_is_free (sm->static_mappings, m));
+  clib_bihash_kv_16_8_t kv;
+  nat44_ed_sm_init_o2i_kv (&kv, addr.as_u32, port, fib_index, proto,
+			   m - sm->static_mappings);
+  return clib_bihash_add_del_16_8 (&sm->flow_hash, &kv, 1 /*is_add*/);
+}
 
-      if (na44_ed_is_fwd_bypass_session (s))
-	{
-	  return;
-	}
+static_always_inline int
+nat44_ed_sm_o2i_del (snat_main_t *sm, ip4_address_t addr, u16 port,
+		     u32 fib_index, u8 proto)
+{
+  clib_bihash_kv_16_8_t kv;
+  nat44_ed_sm_init_o2i_k (&kv, addr.as_u32, port, fib_index, proto);
+  return clib_bihash_add_del_16_8 (&sm->flow_hash, &kv, 0 /*is_add*/);
+}
 
-      if (nat44_ed_is_affinity_session (s))
-	nat_affinity_unlock (s->ext_host_addr, s->out2in.addr, s->nat_proto,
-			     s->out2in.port);
+void
+nat44_ed_free_session_data (snat_main_t *sm, snat_session_t *s,
+			    u32 thread_index, u8 is_ha)
+{
+  per_vrf_sessions_unregister_session (s, thread_index);
 
-      if (!is_ha)
-	nat_syslog_nat44_sdel (
-	  0, s->in2out.fib_index, &s->in2out.addr, s->in2out.port,
-	  &s->ext_host_nat_addr, s->ext_host_nat_port, &s->out2in.addr,
-	  s->out2in.port, &s->ext_host_addr, s->ext_host_port, s->nat_proto,
-	  nat44_ed_is_twice_nat_session (s));
+  if (nat_ed_ses_i2o_flow_hash_add_del (sm, thread_index, s, 0))
+    nat_elog_warn (sm, "flow hash del failed");
 
-      if (snat_is_unk_proto_session (s))
-	return;
+  if (nat_ed_ses_o2i_flow_hash_add_del (sm, thread_index, s, 0))
+    nat_elog_warn (sm, "flow hash del failed");
 
-      if (!is_ha)
-	{
-	  /* log NAT event */
-	  nat_ipfix_logging_nat44_ses_delete (
-	    thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32,
-	    s->nat_proto, s->in2out.port, s->out2in.port, s->in2out.fib_index);
-	}
+  if (na44_ed_is_fwd_bypass_session (s))
+    {
+      return;
+    }
 
-  /* Twice NAT address and port for external host */
-      if (nat44_ed_is_twice_nat_session (s))
-	{
-	  snat_free_outside_address_and_port (
-	    sm->twice_nat_addresses, thread_index, &s->ext_host_nat_addr,
-	    s->ext_host_nat_port, s->nat_proto);
-	}
+  if (nat44_ed_is_affinity_session (s))
+    nat_affinity_unlock (s->ext_host_addr, s->out2in.addr, s->proto,
+			 s->out2in.port);
 
-      if (nat44_ed_is_session_static (s))
-	return;
+  if (!is_ha)
+    nat_syslog_nat44_sdel (0, s->in2out.fib_index, &s->in2out.addr,
+			   s->in2out.port, &s->ext_host_nat_addr,
+			   s->ext_host_nat_port, &s->out2in.addr,
+			   s->out2in.port, &s->ext_host_addr, s->ext_host_port,
+			   s->proto, nat44_ed_is_twice_nat_session (s));
 
-      snat_free_outside_address_and_port (sm->addresses, thread_index,
-					  &s->out2in.addr, s->out2in.port,
-					  s->nat_proto);
+  if (!is_ha)
+    {
+      /* log NAT event */
+      nat_ipfix_logging_nat44_ses_delete (
+	thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32, s->proto,
+	s->in2out.port, s->out2in.port, s->in2out.fib_index);
+    }
 }
 
 static int
@@ -388,7 +389,6 @@ int
 nat44_ed_add_address (ip4_address_t *addr, u32 vrf_id, u8 twice_nat)
 {
   snat_main_t *sm = &snat_main;
-  vlib_thread_main_t *tm = vlib_get_thread_main ();
   snat_address_t *ap, *addresses;
 
   addresses = twice_nat ? sm->twice_nat_addresses : sm->addresses;
@@ -426,16 +426,6 @@ nat44_ed_add_address (ip4_address_t *addr, u32 vrf_id, u8 twice_nat)
 	FIB_PROTOCOL_IP4, vrf_id, sm->fib_src_low);
     }
 
-#define _(N, i, n, s)                                                         \
-  clib_memset (ap->busy_##n##_port_refcounts, 0,                              \
-	       sizeof (ap->busy_##n##_port_refcounts));                       \
-  ap->busy_##n##_ports = 0;                                                   \
-  ap->busy_##n##_ports_per_thread = 0;                                        \
-  vec_validate_init_empty (ap->busy_##n##_ports_per_thread,                   \
-			   tm->n_vlib_mains - 1, 0);
-  foreach_nat_protocol
-#undef _
-
     if (!twice_nat)
   {
     // if we don't have enabled interface we don't add address
@@ -480,7 +470,8 @@ nat44_ed_del_address (ip4_address_t addr, u8 delete_sm, u8 twice_nat)
 	    {
 	      nat44_ed_del_static_mapping (m->local_addr, m->external_addr,
 					   m->local_port, m->external_port,
-					   m->proto, m->vrf_id, ~0, m->flags);
+					   ip_proto_to_nat_proto (m->proto),
+					   m->vrf_id, ~0, m->flags);
 	    }
 	}
     }
@@ -501,32 +492,25 @@ nat44_ed_del_address (ip4_address_t addr, u8 delete_sm, u8 twice_nat)
     }
 
   // delete sessions using address
-  if (a->busy_tcp_ports || a->busy_udp_ports || a->busy_icmp_ports)
+  vec_foreach (tsm, sm->per_thread_data)
     {
-      vec_foreach (tsm, sm->per_thread_data)
+      pool_foreach (ses, tsm->sessions)
 	{
-	  pool_foreach (ses, tsm->sessions)
-	    {
-	      if (ses->out2in.addr.as_u32 == addr.as_u32)
-		{
-		  nat_free_session_data (sm, ses, tsm - sm->per_thread_data,
-					 0);
-		  vec_add1 (ses_to_be_removed, ses - tsm->sessions);
-		}
-	    }
-	  vec_foreach (ses_index, ses_to_be_removed)
+	  if (ses->out2in.addr.as_u32 == addr.as_u32)
 	    {
-	      ses = pool_elt_at_index (tsm->sessions, ses_index[0]);
-	      nat_ed_session_delete (sm, ses, tsm - sm->per_thread_data, 1);
+	      nat44_ed_free_session_data (sm, ses, tsm - sm->per_thread_data,
+					  0);
+	      vec_add1 (ses_to_be_removed, ses - tsm->sessions);
 	    }
-	  vec_free (ses_to_be_removed);
 	}
+      vec_foreach (ses_index, ses_to_be_removed)
+	{
+	  ses = pool_elt_at_index (tsm->sessions, ses_index[0]);
+	  nat_ed_session_delete (sm, ses, tsm - sm->per_thread_data, 1);
+	}
+      vec_free (ses_to_be_removed);
     }
 
-#define _(N, i, n, s) vec_free (a->busy_##n##_ports_per_thread);
-  foreach_nat_protocol
-#undef _
-
     if (!twice_nat)
   {
     vec_del1 (sm->addresses, j);
@@ -569,18 +553,17 @@ nat_ed_static_mapping_del_sessions (snat_main_t * sm,
       }
     if (!addr_only)
       {
-        if ((s->out2in.addr.as_u32 != e_addr.as_u32) ||
-            s->out2in.port != e_port ||
-            s->in2out.port != l_port ||
-            s->nat_proto != protocol)
-          continue;
+	if ((s->out2in.addr.as_u32 != e_addr.as_u32) ||
+	    s->out2in.port != e_port || s->in2out.port != l_port ||
+	    s->proto != protocol)
+	  continue;
       }
 
     if (nat44_ed_is_lb_session (s))
       continue;
     if (!nat44_ed_is_session_static (s))
       continue;
-    nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+    nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
     vec_add1 (indexes_to_free, s - tsm->sessions);
     if (!addr_only)
       break;
@@ -594,89 +577,41 @@ nat_ed_static_mapping_del_sessions (snat_main_t * sm,
   vec_free (indexes_to_free);
 }
 
-int
-nat44_ed_reserve_port (ip4_address_t addr, u16 port, nat_protocol_t proto)
+static_always_inline snat_static_mapping_t *
+nat44_ed_sm_lookup (snat_main_t *sm, clib_bihash_kv_16_8_t *kv)
 {
-  u32 ti = get_thread_idx_by_port (port);
-  snat_main_t *sm = &snat_main;
-  snat_address_t *a = 0;
-  int i;
-
-  for (i = 0; i < vec_len (sm->addresses); i++)
+  clib_bihash_kv_16_8_t v;
+  int rc = clib_bihash_search_16_8 (&sm->flow_hash, kv, &v);
+  if (!rc)
     {
-      a = sm->addresses + i;
-
-      if (a->addr.as_u32 != addr.as_u32)
-	continue;
-
-      switch (proto)
-	{
-#define _(N, j, n, s)                                                         \
-  case NAT_PROTOCOL_##N:                                                      \
-    if (a->busy_##n##_port_refcounts[port])                                   \
-      goto done;                                                              \
-    ++a->busy_##n##_port_refcounts[port];                                     \
-    if (port > 1024)                                                          \
-      {                                                                       \
-	a->busy_##n##_ports++;                                                \
-	a->busy_##n##_ports_per_thread[ti]++;                                 \
-      }                                                                       \
-    break;
-	  foreach_nat_protocol
-#undef _
-	    default : nat_elog_info (sm, "unknown protocol");
-	  goto done;
-	}
-
-      return 0;
+      ASSERT (0 == ed_value_get_thread_index (&v));
+      return pool_elt_at_index (sm->static_mappings,
+				ed_value_get_session_index (&v));
     }
-
-done:
-  return 1;
+  return NULL;
 }
 
-int
-nat44_ed_free_port (ip4_address_t addr, u16 port, nat_protocol_t proto)
+snat_static_mapping_t *
+nat44_ed_sm_o2i_lookup (snat_main_t *sm, ip4_address_t addr, u16 port,
+			u32 fib_index, u8 proto)
 {
-  u32 ti = get_thread_idx_by_port (port);
-  snat_main_t *sm = &snat_main;
-  snat_address_t *a = 0;
-  int i;
-
-  for (i = 0; i < vec_len (sm->addresses); i++)
-    {
-      a = sm->addresses + i;
-
-      if (a->addr.as_u32 != addr.as_u32)
-	continue;
-
-      switch (proto)
-	{
-#define _(N, j, n, s)                                                         \
-  case NAT_PROTOCOL_##N:                                                      \
-    --a->busy_##n##_port_refcounts[port];                                     \
-    if (port > 1024)                                                          \
-      {                                                                       \
-	a->busy_##n##_ports--;                                                \
-	a->busy_##n##_ports_per_thread[ti]--;                                 \
-      }                                                                       \
-    break;
-	  foreach_nat_protocol
-#undef _
-	    default : nat_elog_info (sm, "unknown protocol");
-	  goto done;
-	}
-
-      return 0;
-    }
+  clib_bihash_kv_16_8_t kv;
+  nat44_ed_sm_init_o2i_k (&kv, addr.as_u32, port, fib_index, proto);
+  return nat44_ed_sm_lookup (sm, &kv);
+}
 
-done:
-  return 1;
+snat_static_mapping_t *
+nat44_ed_sm_i2o_lookup (snat_main_t *sm, ip4_address_t addr, u16 port,
+			u32 fib_index, u8 proto)
+{
+  clib_bihash_kv_16_8_t kv;
+  nat44_ed_sm_init_i2o_k (&kv, addr.as_u32, port, fib_index, proto);
+  return nat44_ed_sm_lookup (sm, &kv);
 }
 
 void
 nat44_ed_add_resolve_record (ip4_address_t l_addr, u16 l_port, u16 e_port,
-			     nat_protocol_t proto, u32 vrf_id, u32 sw_if_index,
+			     ip_protocol_t proto, u32 vrf_id, u32 sw_if_index,
 			     u32 flags, ip4_address_t pool_addr, u8 *tag)
 {
   snat_static_map_resolve_t *rp;
@@ -696,7 +631,7 @@ nat44_ed_add_resolve_record (ip4_address_t l_addr, u16 l_port, u16 e_port,
 
 int
 nat44_ed_get_resolve_record (ip4_address_t l_addr, u16 l_port, u16 e_port,
-			     nat_protocol_t proto, u32 vrf_id, u32 sw_if_index,
+			     ip_protocol_t proto, u32 vrf_id, u32 sw_if_index,
 			     u32 flags, int *out)
 {
   snat_static_map_resolve_t *rp;
@@ -746,7 +681,7 @@ nat44_ed_get_resolve_record (ip4_address_t l_addr, u16 l_port, u16 e_port,
 
 int
 nat44_ed_del_resolve_record (ip4_address_t l_addr, u16 l_port, u16 e_port,
-			     nat_protocol_t proto, u32 vrf_id, u32 sw_if_index,
+			     ip_protocol_t proto, u32 vrf_id, u32 sw_if_index,
 			     u32 flags)
 {
   snat_main_t *sm = &snat_main;
@@ -779,14 +714,24 @@ nat44_ed_validate_sm_input (u32 flags)
   return 0;
 }
 
+snat_address_t *
+nat44_ed_addr_lookup (snat_main_t *sm, u32 addr)
+{
+  for (int i = 0; i < vec_len (sm->addresses); ++i)
+    {
+      if (sm->addresses[i].addr.as_u32 == addr)
+	return &sm->addresses[i];
+    }
+  return NULL;
+}
+
 int
 nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
-			     u16 l_port, u16 e_port, nat_protocol_t proto,
+			     u16 l_port, u16 e_port, ip_protocol_t proto,
 			     u32 vrf_id, u32 sw_if_index, u32 flags,
 			     ip4_address_t pool_addr, u8 *tag)
 {
   snat_main_t *sm = &snat_main;
-  clib_bihash_kv_8_8_t kv, value;
   nat44_lb_addr_port_t *local;
   snat_static_mapping_t *m;
   u32 fib_index = ~0;
@@ -840,12 +785,9 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       l_addr.as_u32 = e_addr.as_u32;
     }
 
-  // fib index 0
-  init_nat_k (&kv, e_addr, e_port, 0, proto);
-
-  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
+  if (m)
     {
-      m = pool_elt_at_index (sm->static_mappings, value.value);
       if (!is_sm_identity_nat (m->flags))
 	{
 	  return VNET_API_ERROR_VALUE_EXIST;
@@ -867,9 +809,8 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       local->fib_index = fib_table_find_or_create_and_lock (
 	FIB_PROTOCOL_IP4, vrf_id, sm->fib_src_low);
 
-      init_nat_kv (&kv, m->local_addr, m->local_port, local->fib_index,
-		   m->proto, 0, m - sm->static_mappings);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
+      nat44_ed_sm_i2o_add (sm, m, m->local_addr, m->local_port,
+			   local->fib_index, m->proto);
 
       return 0;
     }
@@ -891,8 +832,7 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
   // identity nat supports multiple records in local mapping
   if (!(is_sm_out2in_only (flags) || is_sm_identity_nat (flags)))
     {
-      init_nat_k (&kv, l_addr, l_port, fib_index, proto);
-      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
+      if (nat44_ed_sm_i2o_lookup (sm, l_addr, l_port, fib_index, proto))
 	{
 	  return VNET_API_ERROR_VALUE_EXIST;
 	}
@@ -901,7 +841,7 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
   if (!(is_sm_out2in_only (flags) || is_sm_addr_only (flags) ||
 	sm->static_mapping_only))
     {
-      if (nat44_ed_reserve_port (e_addr, e_port, proto))
+      if (!nat44_ed_addr_lookup (sm, e_addr.as_u32))
 	{
 	  // remove resolve record
 	  if (is_sm_switch_address (flags) && !is_sm_identity_nat (flags))
@@ -955,14 +895,11 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
   if (!is_sm_out2in_only (flags))
     {
-      init_nat_kv (&kv, m->local_addr, m->local_port, fib_index, m->proto, 0,
-		   m - sm->static_mappings);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
+      nat44_ed_sm_i2o_add (sm, m, m->local_addr, m->local_port, fib_index,
+			   m->proto);
     }
 
-  init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto, 0,
-	       m - sm->static_mappings);
-  clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 1);
+  nat44_ed_sm_o2i_add (sm, m, m->external_addr, m->external_port, 0, m->proto);
 
   if (sm->num_workers > 1)
     {
@@ -981,13 +918,12 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
 int
 nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
-			     u16 l_port, u16 e_port, nat_protocol_t proto,
+			     u16 l_port, u16 e_port, ip_protocol_t proto,
 			     u32 vrf_id, u32 sw_if_index, u32 flags)
 {
   snat_main_per_thread_data_t *tsm;
   snat_main_t *sm = &snat_main;
 
-  clib_bihash_kv_8_8_t kv, value;
   nat44_lb_addr_port_t *local;
   snat_static_mapping_t *m;
   u32 fib_index = ~0;
@@ -1039,9 +975,9 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     }
 
   // fib index 0
-  init_nat_k (&kv, e_addr, e_port, 0, proto);
+  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
 
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+  if (!m)
     {
       if (is_sm_switch_address (flags))
 	{
@@ -1050,8 +986,6 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       return VNET_API_ERROR_NO_SUCH_ENTRY;
     }
 
-  m = pool_elt_at_index (sm->static_mappings, value.value);
-
   if (is_sm_identity_nat (flags))
     {
       u8 failure = 1;
@@ -1085,7 +1019,7 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
   if (!(is_sm_out2in_only (flags) || is_sm_addr_only (flags) ||
 	sm->static_mapping_only))
     {
-      if (nat44_ed_free_port (e_addr, e_port, proto))
+      if (!nat44_ed_addr_lookup (sm, e_addr.as_u32))
 	{
 	  return VNET_API_ERROR_INVALID_VALUE;
 	}
@@ -1093,8 +1027,7 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
   if (!is_sm_out2in_only (flags))
     {
-      init_nat_k (&kv, l_addr, l_port, fib_index, proto);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0);
+      nat44_ed_sm_i2o_del (sm, l_addr, l_port, fib_index, proto);
     }
 
   if (!sm->static_mapping_only || sm->static_mapping_connection_tracking)
@@ -1116,8 +1049,7 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     {
       // this is last record remove all required stuff
       // fib_index 0
-      init_nat_k (&kv, e_addr, e_port, 0, proto);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0);
+      nat44_ed_sm_o2i_del (sm, e_addr, e_port, 0, proto);
 
       vec_free (m->tag);
       vec_free (m->workers);
@@ -1134,17 +1066,17 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
 int
 nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
-				nat_protocol_t proto,
+				ip_protocol_t proto,
 				nat44_lb_addr_port_t *locals, u32 flags,
 				u8 *tag, u32 affinity)
 {
   snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m;
-  clib_bihash_kv_8_8_t kv, value;
   snat_address_t *a = 0;
 
   nat44_lb_addr_port_t *local;
   uword *bitmap = 0;
+  int rc = 0;
 
   int i;
 
@@ -1153,15 +1085,7 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       return VNET_API_ERROR_UNSUPPORTED;
     }
 
-  init_nat_k (&kv, e_addr, e_port, 0, proto);
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
-    {
-      m = 0;
-    }
-  else
-    {
-      m = pool_elt_at_index (sm->static_mappings, value.value);
-    }
+  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
 
   if (m)
     {
@@ -1181,25 +1105,11 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	{
 	  if (sm->addresses[i].addr.as_u32 == e_addr.as_u32)
 	    {
-	      a = sm->addresses + i;
 	      /* External port must be unused */
-	      switch (proto)
+	      a = sm->addresses + i;
+	      if (nat44_ed_sm_o2i_lookup (sm, a->addr, e_port, 0, proto))
 		{
-#define _(N, j, n, s)                                                         \
-  case NAT_PROTOCOL_##N:                                                      \
-    if (a->busy_##n##_port_refcounts[e_port])                                 \
-      return VNET_API_ERROR_INVALID_VALUE;                                    \
-    ++a->busy_##n##_port_refcounts[e_port];                                   \
-    if (e_port > 1024)                                                        \
-      {                                                                       \
-	a->busy_##n##_ports++;                                                \
-	a->busy_##n##_ports_per_thread[get_thread_idx_by_port (e_port)]++;    \
-      }                                                                       \
-    break;
-		  foreach_nat_protocol
-#undef _
-		    default : nat_elog_info (sm, "unknown protocol");
-		  return VNET_API_ERROR_INVALID_VALUE_2;
+		  return VNET_API_ERROR_VALUE_EXIST;
 		}
 	      break;
 	    }
@@ -1228,11 +1138,10 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
   else
     m->affinity_per_service_list_head_index = ~0;
 
-  init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto, 0,
-	       m - sm->static_mappings);
-  if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 1))
+  if (nat44_ed_sm_o2i_add (sm, m, m->external_addr, m->external_port, 0,
+			   m->proto))
     {
-      nat_elog_err (sm, "static_mapping_by_external key add failed");
+      nat_elog_err (sm, "sm o2i key add failed");
       return VNET_API_ERROR_UNSPECIFIED;
     }
 
@@ -1242,10 +1151,16 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	FIB_PROTOCOL_IP4, locals[i].vrf_id, sm->fib_src_low);
       if (!is_sm_out2in_only (flags))
 	{
-	  init_nat_kv (&kv, locals[i].addr, locals[i].port,
-		       locals[i].fib_index, m->proto, 0,
-		       m - sm->static_mappings);
-	  clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
+	  if (nat44_ed_sm_o2i_add (sm, m, e_addr, e_port, 0, proto))
+	    {
+	      nat_elog_err (sm, "sm o2i key add failed");
+	      rc = VNET_API_ERROR_UNSPECIFIED;
+	      // here we continue with add operation so that it can be safely
+	      // reversed in delete path - otherwise we'd have to track what
+	      // we've done and deal with partial cleanups and since bihash
+	      // adds are (extremely improbable) the only points of failure,
+	      // it's easier to just do it this way
+	    }
 	}
       locals[i].prefix = (i == 0) ?
 			   locals[i].probability :
@@ -1272,72 +1187,36 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	}
     }
 
-  return 0;
+  return rc;
 }
 
 int
 nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
-				nat_protocol_t proto, u32 flags)
+				ip_protocol_t proto, u32 flags)
 {
   snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m;
-  clib_bihash_kv_8_8_t kv, value;
-  snat_address_t *a = 0;
 
   nat44_lb_addr_port_t *local;
   snat_main_per_thread_data_t *tsm;
   snat_session_t *s;
-  int i;
 
   if (!sm->enabled)
     {
       return VNET_API_ERROR_UNSUPPORTED;
     }
 
-  init_nat_k (&kv, e_addr, e_port, 0, proto);
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
-    m = 0;
-  else
-    m = pool_elt_at_index (sm->static_mappings, value.value);
-
+  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
   if (!m)
     return VNET_API_ERROR_NO_SUCH_ENTRY;
 
   if (!is_sm_lb (m->flags))
     return VNET_API_ERROR_INVALID_VALUE;
 
-  if (!(sm->static_mapping_only || is_sm_out2in_only (flags)))
+  if (nat44_ed_sm_o2i_del (sm, m->external_addr, m->external_port, 0,
+			   m->proto))
     {
-      for (i = 0; i < vec_len (sm->addresses); i++)
-	{
-	  if (sm->addresses[i].addr.as_u32 == e_addr.as_u32)
-	    {
-	      a = sm->addresses + i;
-	      switch (proto)
-		{
-#define _(N, j, n, s)                                                         \
-  case NAT_PROTOCOL_##N:                                                      \
-    --a->busy_##n##_port_refcounts[e_port];                                   \
-    if (e_port > 1024)                                                        \
-      {                                                                       \
-	a->busy_##n##_ports--;                                                \
-	a->busy_##n##_ports_per_thread[get_thread_idx_by_port (e_port)]--;    \
-      }                                                                       \
-    break;
-		  foreach_nat_protocol
-#undef _
-		    default : nat_elog_info (sm, "unknown protocol");
-		  return VNET_API_ERROR_INVALID_VALUE_2;
-		}
-	      break;
-	    }
-	}
-    }
-
-  init_nat_k (&kv, m->external_addr, m->external_port, 0, m->proto);
-  if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0))
-    {
-      nat_elog_err (sm, "static_mapping_by_external key del failed");
+      nat_elog_err (sm, "sm o2i key del failed");
       return VNET_API_ERROR_UNSPECIFIED;
     }
 
@@ -1346,11 +1225,10 @@ nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       fib_table_unlock (local->fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
       if (!is_sm_out2in_only (flags))
 	{
-	  init_nat_k (&kv, local->addr, local->port, local->fib_index,
-		      m->proto);
-	  if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0))
+	  if (nat44_ed_sm_i2o_del (sm, local->addr, local->port,
+				   local->fib_index, m->proto))
 	    {
-	      nat_elog_err (sm, "static_mapping_by_local key del failed");
+	      nat_elog_err (sm, "sm i2o key del failed");
 	      return VNET_API_ERROR_UNSPECIFIED;
 	    }
 	}
@@ -1377,7 +1255,7 @@ nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	      s->in2out.port != local->port)
 	    continue;
 
-	  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+	  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
 	  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
 	}
     }
@@ -1398,12 +1276,11 @@ nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 int
 nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 					  ip4_address_t l_addr, u16 l_port,
-					  nat_protocol_t proto, u32 vrf_id,
+					  ip_protocol_t proto, u32 vrf_id,
 					  u8 probability, u8 is_add)
 {
   snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m = 0;
-  clib_bihash_kv_8_8_t kv, value;
   nat44_lb_addr_port_t *local, *prev_local, *match_local = 0;
   snat_main_per_thread_data_t *tsm;
   snat_session_t *s;
@@ -1416,9 +1293,7 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
       return VNET_API_ERROR_UNSUPPORTED;
     }
 
-  init_nat_k (&kv, e_addr, e_port, 0, proto);
-  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
-    m = pool_elt_at_index (sm->static_mappings, value.value);
+  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
 
   if (!m)
     {
@@ -1459,10 +1334,13 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 
       if (!is_sm_out2in_only (m->flags))
 	{
-	  init_nat_kv (&kv, l_addr, l_port, local->fib_index, proto, 0,
-		       m - sm->static_mappings);
-	  if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1))
-	    nat_elog_err (sm, "static_mapping_by_local key add failed");
+	  if (nat44_ed_sm_i2o_add (sm, m, l_addr, l_port, local->fib_index,
+				   proto))
+	    {
+	      nat_elog_err (sm, "sm i2o key add failed");
+	      pool_put (m->locals, local);
+	      return VNET_API_ERROR_UNSPECIFIED;
+	    }
 	}
     }
   else
@@ -1478,9 +1356,9 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 
       if (!is_sm_out2in_only (m->flags))
 	{
-	  init_nat_k (&kv, l_addr, l_port, match_local->fib_index, proto);
-	  if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0))
-	    nat_elog_err (sm, "static_mapping_by_local key del failed");
+	  if (nat44_ed_sm_i2o_del (sm, l_addr, l_port, match_local->fib_index,
+				   proto))
+	    nat_elog_err (sm, "sm i2o key del failed");
 	}
 
       if (sm->num_workers > 1)
@@ -1504,7 +1382,7 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 	      s->in2out.port != match_local->port)
 	    continue;
 
-	  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+	  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
 	  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
       }
 
@@ -2163,8 +2041,8 @@ test_key_calc_split ()
   u32 thread_index = 3000000001;
   u32 session_index = 3000000221;
   clib_bihash_kv_16_8_t kv;
-  init_ed_kv (&kv, l_addr, l_port, r_addr, r_port, fib_index, proto,
-	      thread_index, session_index);
+  init_ed_kv (&kv, l_addr.as_u32, l_port, r_addr.as_u32, r_port, fib_index,
+	      proto, thread_index, session_index);
   ip4_address_t l_addr2;
   ip4_address_t r_addr2;
   clib_memset (&l_addr2, 0, sizeof (l_addr2));
@@ -2183,16 +2061,6 @@ test_key_calc_split ()
   ASSERT (fib_index == fib_index2);
   ASSERT (thread_index == ed_value_get_thread_index (&kv));
   ASSERT (session_index == ed_value_get_session_index (&kv));
-
-  fib_index = 7001;
-  proto = 5;
-  nat_protocol_t proto3 = ~0;
-  u64 key = calc_nat_key (l_addr, l_port, fib_index, proto);
-  split_nat_key (key, &l_addr2, &l_port2, &fib_index2, &proto3);
-  ASSERT (l_addr.as_u32 == l_addr2.as_u32);
-  ASSERT (l_port == l_port2);
-  ASSERT (proto == proto3);
-  ASSERT (fib_index == fib_index2);
 }
 
 static clib_error_t *
@@ -2441,14 +2309,6 @@ nat44_plugin_enable (nat44_config_t c)
 void
 nat44_addresses_free (snat_address_t ** addresses)
 {
-  snat_address_t *ap;
-  vec_foreach (ap, *addresses)
-    {
-    #define _(N, i, n, s) \
-      vec_free (ap->busy_##n##_ports_per_thread);
-      foreach_nat_protocol
-    #undef _
-    }
   vec_free (*addresses);
   *addresses = 0;
 }
@@ -2548,7 +2408,7 @@ nat44_ed_forwarding_enable_disable (u8 is_enable)
       vec_foreach (ses_index, ses_to_be_removed)
 	{
 	  s = pool_elt_at_index (tsm->sessions, ses_index[0]);
-	  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+	  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
 	  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
 	}
 
@@ -2556,88 +2416,88 @@ nat44_ed_forwarding_enable_disable (u8 is_enable)
     }
 }
 
-void
-snat_free_outside_address_and_port (snat_address_t *addresses,
-				    u32 thread_index, ip4_address_t *addr,
-				    u16 port, nat_protocol_t protocol)
+static_always_inline snat_static_mapping_t *
+nat44_ed_sm_match (snat_main_t *sm, ip4_address_t match_addr, u16 match_port,
+		   u32 match_fib_index, ip_protocol_t match_protocol,
+		   int by_external)
 {
-  snat_main_t *sm = &snat_main;
-  snat_address_t *a;
-  u32 address_index;
-  u16 port_host_byte_order = clib_net_to_host_u16 (port);
-
-  for (address_index = 0; address_index < vec_len (addresses);
-       address_index++)
+  snat_static_mapping_t *m;
+  if (!by_external)
     {
-      if (addresses[address_index].addr.as_u32 == addr->as_u32)
-	break;
-    }
+      m = nat44_ed_sm_i2o_lookup (sm, match_addr, match_port, match_fib_index,
+				  match_protocol);
+      if (m)
+	return m;
 
-  ASSERT (address_index < vec_len (addresses));
+      /* Try address only mapping */
+      m = nat44_ed_sm_i2o_lookup (sm, match_addr, 0, match_fib_index, 0);
+      if (m)
+	return m;
+
+      if (sm->inside_fib_index != match_fib_index)
+	{
+	  m = nat44_ed_sm_i2o_lookup (sm, match_addr, match_port,
+				      sm->inside_fib_index, match_protocol);
+	  if (m)
+	    return m;
 
-  a = addresses + address_index;
+	  /* Try address only mapping */
+	  m = nat44_ed_sm_i2o_lookup (sm, match_addr, 0, sm->inside_fib_index,
+				      0);
+	  if (m)
+	    return m;
+	}
+      if (sm->outside_fib_index != match_fib_index)
+	{
+	  m = nat44_ed_sm_i2o_lookup (sm, match_addr, match_port,
+				      sm->outside_fib_index, match_protocol);
+	  if (m)
+	    return m;
 
-  switch (protocol)
+	  /* Try address only mapping */
+	  m = nat44_ed_sm_i2o_lookup (sm, match_addr, 0, sm->outside_fib_index,
+				      0);
+	  if (m)
+	    return m;
+	}
+    }
+  else
     {
-#define _(N, i, n, s) \
-    case NAT_PROTOCOL_##N: \
-      ASSERT (a->busy_##n##_port_refcounts[port_host_byte_order] >= 1); \
-      --a->busy_##n##_port_refcounts[port_host_byte_order]; \
-      a->busy_##n##_ports--; \
-      a->busy_##n##_ports_per_thread[thread_index]--; \
-      break;
-      foreach_nat_protocol
-#undef _
-	default : nat_elog_info (sm, "unknown protocol");
-      return;
+      m =
+	nat44_ed_sm_o2i_lookup (sm, match_addr, match_port, 0, match_protocol);
+      if (m)
+	return m;
+
+      /* Try address only mapping */
+      m = nat44_ed_sm_o2i_lookup (sm, match_addr, 0, 0, 0);
+      if (m)
+	return m;
     }
+  return 0;
 }
 
 int
 snat_static_mapping_match (vlib_main_t *vm, snat_main_t *sm,
 			   ip4_address_t match_addr, u16 match_port,
-			   u32 match_fib_index, nat_protocol_t match_protocol,
+			   u32 match_fib_index, ip_protocol_t match_protocol,
 			   ip4_address_t *mapping_addr, u16 *mapping_port,
-			   u32 *mapping_fib_index, u8 by_external,
+			   u32 *mapping_fib_index, int by_external,
 			   u8 *is_addr_only, twice_nat_type_t *twice_nat,
 			   lb_nat_type_t *lb, ip4_address_t *ext_host_addr,
 			   u8 *is_identity_nat, snat_static_mapping_t **out)
 {
-  clib_bihash_kv_8_8_t kv, value;
-  clib_bihash_8_8_t *mapping_hash;
   snat_static_mapping_t *m;
   u32 rand, lo = 0, hi, mid, *tmp = 0, i;
   nat44_lb_addr_port_t *local;
   u8 backend_index;
 
-  if (!by_external)
-    {
-      mapping_hash = &sm->static_mapping_by_local;
-      init_nat_k (&kv, match_addr, match_port, match_fib_index,
-		  match_protocol);
-      if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
-	{
-	  /* Try address only mapping */
-	  init_nat_k (&kv, match_addr, 0, match_fib_index, 0);
-	  if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
-	    return 1;
-	}
-    }
-  else
+  m = nat44_ed_sm_match (sm, match_addr, match_port, match_fib_index,
+			 match_protocol, by_external);
+  if (!m)
     {
-      mapping_hash = &sm->static_mapping_by_external;
-      init_nat_k (&kv, match_addr, match_port, 0, match_protocol);
-      if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
-	{
-	  /* Try address only mapping */
-	  init_nat_k (&kv, match_addr, 0, 0, 0);
-	  if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
-	    return 1;
-	}
+      return 1;
     }
 
-  m = pool_elt_at_index (sm->static_mappings, value.value);
-
   if (by_external)
     {
       if (is_sm_lb (m->flags))
@@ -2814,8 +2674,9 @@ nat44_ed_get_in2out_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 		b, ip, &lookup_saddr, &lookup_sport, &lookup_daddr,
 		&lookup_dport, &lookup_protocol))
 	    {
-	      init_ed_k (&kv16, lookup_saddr, lookup_sport, lookup_daddr,
-			 lookup_dport, rx_fib_index, lookup_protocol);
+	      init_ed_k (&kv16, lookup_saddr.as_u32, lookup_sport,
+			 lookup_daddr.as_u32, lookup_dport, rx_fib_index,
+			 lookup_protocol);
 	      if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16))
 		{
 		  next_worker_index = ed_value_get_thread_index (&value16);
@@ -2826,9 +2687,10 @@ nat44_ed_get_in2out_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	    }
 	}
 
-      init_ed_k (&kv16, ip->src_address, vnet_buffer (b)->ip.reass.l4_src_port,
-		 ip->dst_address, vnet_buffer (b)->ip.reass.l4_dst_port,
-		 fib_index, ip->protocol);
+      init_ed_k (&kv16, ip->src_address.as_u32,
+		 vnet_buffer (b)->ip.reass.l4_src_port, ip->dst_address.as_u32,
+		 vnet_buffer (b)->ip.reass.l4_dst_port, fib_index,
+		 ip->protocol);
 
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16))
 	{
@@ -2839,9 +2701,10 @@ nat44_ed_get_in2out_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	}
 
       // dst NAT
-      init_ed_k (&kv16, ip->dst_address, vnet_buffer (b)->ip.reass.l4_dst_port,
-		 ip->src_address, vnet_buffer (b)->ip.reass.l4_src_port,
-		 rx_fib_index, ip->protocol);
+      init_ed_k (&kv16, ip->dst_address.as_u32,
+		 vnet_buffer (b)->ip.reass.l4_dst_port, ip->src_address.as_u32,
+		 vnet_buffer (b)->ip.reass.l4_src_port, rx_fib_index,
+		 ip->protocol);
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16))
 	{
 	  next_worker_index = ed_value_get_thread_index (&value16);
@@ -2883,17 +2746,16 @@ nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 				  u32 rx_fib_index, u8 is_output)
 {
   snat_main_t *sm = &snat_main;
-  clib_bihash_kv_8_8_t kv, value;
   clib_bihash_kv_16_8_t kv16, value16;
 
-  u32 proto, next_worker_index = 0;
+  u8 proto, next_worker_index = 0;
   u16 port;
   snat_static_mapping_t *m;
   u32 hash;
 
-  proto = ip_proto_to_nat_proto (ip->protocol);
+  proto = ip->protocol;
 
-  if (PREDICT_FALSE (proto == NAT_PROTOCOL_ICMP))
+  if (PREDICT_FALSE (IP_PROTOCOL_ICMP == proto))
     {
       ip4_address_t lookup_saddr, lookup_daddr;
       u16 lookup_sport, lookup_dport;
@@ -2902,8 +2764,9 @@ nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	    b, ip, &lookup_saddr, &lookup_sport, &lookup_daddr, &lookup_dport,
 	    &lookup_protocol))
 	{
-	  init_ed_k (&kv16, lookup_saddr, lookup_sport, lookup_daddr,
-		     lookup_dport, rx_fib_index, lookup_protocol);
+	  init_ed_k (&kv16, lookup_saddr.as_u32, lookup_sport,
+		     lookup_daddr.as_u32, lookup_dport, rx_fib_index,
+		     lookup_protocol);
 	  if (PREDICT_TRUE (
 		!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16)))
 	    {
@@ -2917,9 +2780,10 @@ nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	}
     }
 
-  init_ed_k (&kv16, ip->src_address, vnet_buffer (b)->ip.reass.l4_src_port,
-	     ip->dst_address, vnet_buffer (b)->ip.reass.l4_dst_port,
-	     rx_fib_index, ip->protocol);
+  init_ed_k (&kv16, ip->src_address.as_u32,
+	     vnet_buffer (b)->ip.reass.l4_src_port, ip->dst_address.as_u32,
+	     vnet_buffer (b)->ip.reass.l4_dst_port, rx_fib_index,
+	     ip->protocol);
 
   if (PREDICT_TRUE (
 	!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16)))
@@ -2937,18 +2801,18 @@ nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
   /* first try static mappings without port */
   if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
     {
-      init_nat_k (&kv, ip->dst_address, 0, 0, 0);
-      if (!clib_bihash_search_8_8
-	  (&sm->static_mapping_by_external, &kv, &value))
+      m = nat44_ed_sm_o2i_lookup (sm, ip->dst_address, 0, 0, proto);
+      if (m)
 	{
-	  m = pool_elt_at_index (sm->static_mappings, value.value);
-	  next_worker_index = m->workers[0];
-	  goto done;
+	  {
+	    next_worker_index = m->workers[0];
+	    goto done;
+	  }
 	}
     }
 
   /* unknown protocol */
-  if (PREDICT_FALSE (proto == NAT_PROTOCOL_OTHER))
+  if (PREDICT_FALSE (nat44_ed_is_unk_proto (proto)))
     {
       /* use current thread */
       next_worker_index = vlib_get_thread_index ();
@@ -2969,17 +2833,18 @@ nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	{
 	  /* if error message, then it's not fragmented and we can access it */
 	  ip4_header_t *inner_ip = (ip4_header_t *) (echo + 1);
-	  proto = ip_proto_to_nat_proto (inner_ip->protocol);
+	  proto = inner_ip->protocol;
 	  void *l4_header = ip4_next_header (inner_ip);
 	  switch (proto)
 	    {
-	    case NAT_PROTOCOL_ICMP:
+	    case IP_PROTOCOL_ICMP:
 	      icmp = (icmp46_header_t *) l4_header;
 	      echo = (icmp_echo_header_t *) (icmp + 1);
 	      port = echo->identifier;
 	      break;
-	    case NAT_PROTOCOL_UDP:
-	    case NAT_PROTOCOL_TCP:
+	    case IP_PROTOCOL_UDP:
+	      /* breakthrough */
+	    case IP_PROTOCOL_TCP:
 	      port = ((tcp_udp_header_t *) l4_header)->src_port;
 	      break;
 	    default:
@@ -2992,11 +2857,9 @@ nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
   /* try static mappings with port */
   if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
     {
-      init_nat_k (&kv, ip->dst_address, port, 0, proto);
-      if (!clib_bihash_search_8_8
-	  (&sm->static_mapping_by_external, &kv, &value))
+      m = nat44_ed_sm_o2i_lookup (sm, ip->dst_address, port, 0, proto);
+      if (m)
 	{
-	  m = pool_elt_at_index (sm->static_mappings, value.value);
 	  if (!is_sm_lb (m->flags))
 	    {
 	      next_worker_index = m->workers[0];
@@ -3126,23 +2989,9 @@ nat44_ed_db_init (u32 translations, u32 translation_buckets)
 {
   snat_main_t *sm = &snat_main;
   snat_main_per_thread_data_t *tsm;
-  u32 static_mapping_buckets = 1024;
-  u32 static_mapping_memory_size = 64 << 20;
 
   reinit_ed_flow_hash ();
 
-  clib_bihash_init_8_8 (&sm->static_mapping_by_local,
-			"static_mapping_by_local", static_mapping_buckets,
-			static_mapping_memory_size);
-  clib_bihash_set_kvp_format_fn_8_8 (&sm->static_mapping_by_local,
-				     format_static_mapping_kvp);
-
-  clib_bihash_init_8_8 (&sm->static_mapping_by_external,
-			"static_mapping_by_external", static_mapping_buckets,
-			static_mapping_memory_size);
-  clib_bihash_set_kvp_format_fn_8_8 (&sm->static_mapping_by_external,
-				     format_static_mapping_kvp);
-
   if (sm->pat)
     {
       vec_foreach (tsm, sm->per_thread_data)
@@ -3169,8 +3018,6 @@ nat44_ed_db_free ()
 
   pool_free (sm->static_mappings);
   clib_bihash_free_16_8 (&sm->flow_hash);
-  clib_bihash_free_8_8 (&sm->static_mapping_by_local);
-  clib_bihash_free_8_8 (&sm->static_mapping_by_external);
 
   if (sm->pat)
     {
@@ -3207,7 +3054,6 @@ nat44_ed_add_del_static_mapping_addr_only_cb (
   ip4_main_t *im, uword opaque, u32 sw_if_index, ip4_address_t *address,
   u32 address_length, u32 if_address_index, u32 is_delete)
 {
-  clib_bihash_kv_8_8_t kv, value;
   snat_static_map_resolve_t *rp;
   snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m;
@@ -3233,17 +3079,8 @@ nat44_ed_add_del_static_mapping_addr_only_cb (
       return;
     }
 
-  init_nat_k (&kv, *address, rp->addr_only ? 0 : rp->e_port,
-	      sm->outside_fib_index, rp->addr_only ? 0 : rp->proto);
-
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
-    {
-      m = 0;
-    }
-  else
-    {
-      m = pool_elt_at_index (sm->static_mappings, value.value);
-    }
+  m = nat44_ed_sm_o2i_lookup (sm, *address, rp->addr_only ? 0 : rp->e_port, 0,
+			      rp->proto);
 
   if (is_delete)
     {
@@ -3486,7 +3323,8 @@ nat44_ed_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
   else
     tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
-  init_ed_k (&kv, *addr, port, *eh_addr, eh_port, fib_index, proto);
+  init_ed_k (&kv, addr->as_u32, port, eh_addr->as_u32, eh_port, fib_index,
+	     proto);
   if (clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     {
       return VNET_API_ERROR_NO_SUCH_ENTRY;
@@ -3495,7 +3333,7 @@ nat44_ed_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
   if (pool_is_free_index (tsm->sessions, ed_value_get_session_index (&value)))
     return VNET_API_ERROR_UNSPECIFIED;
   s = pool_elt_at_index (tsm->sessions, ed_value_get_session_index (&value));
-  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
   nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
   return 0;
 }
@@ -3601,13 +3439,13 @@ nat_6t_flow_icmp_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 
 static_always_inline void
 nat_6t_flow_ip4_translate (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
-			   nat_6t_flow_t *f, nat_protocol_t proto,
+			   nat_6t_flow_t *f, ip_protocol_t proto,
 			   int is_icmp_inner_ip4, int skip_saddr_rewrite)
 {
   udp_header_t *udp = ip4_next_header (ip);
   tcp_header_t *tcp = (tcp_header_t *) udp;
 
-  if ((NAT_PROTOCOL_TCP == proto || NAT_PROTOCOL_UDP == proto) &&
+  if ((IP_PROTOCOL_TCP == proto || IP_PROTOCOL_UDP == proto) &&
       !vnet_buffer (b)->ip.reass.is_non_first_fragment)
     {
       if (!is_icmp_inner_ip4)
@@ -3625,7 +3463,7 @@ nat_6t_flow_ip4_translate (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
 	  udp->dst_port = f->rewrite.sport;
 	}
 
-      if (NAT_PROTOCOL_TCP == proto)
+      if (IP_PROTOCOL_TCP == proto)
 	{
 	  ip_csum_t tcp_sum = tcp->checksum;
 	  tcp_sum = ip_csum_sub_even (tcp_sum, f->l3_csum_delta);
@@ -3633,7 +3471,7 @@ nat_6t_flow_ip4_translate (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
 	  mss_clamping (sm->mss_clamping, tcp, &tcp_sum);
 	  tcp->checksum = ip_csum_fold (tcp_sum);
 	}
-      else if (proto == NAT_PROTOCOL_UDP && udp->checksum)
+      else if (IP_PROTOCOL_UDP == proto && udp->checksum)
 	{
 	  ip_csum_t udp_sum = udp->checksum;
 	  udp_sum = ip_csum_sub_even (udp_sum, f->l3_csum_delta);
@@ -3731,8 +3569,7 @@ nat_6t_flow_icmp_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 	      return NAT_ED_TRNSL_ERR_INNER_IP_CORRUPT;
 	    }
 
-	  nat_protocol_t inner_proto =
-	    ip_proto_to_nat_proto (inner_ip->protocol);
+	  ip_protocol_t inner_proto = inner_ip->protocol;
 
 	  ip_csum_t old_icmp_sum = icmp->checksum;
 	  ip_csum_t old_inner_ip_sum = inner_ip->checksum;
@@ -3744,7 +3581,7 @@ nat_6t_flow_icmp_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 
 	  switch (inner_proto)
 	    {
-	    case NAT_PROTOCOL_UDP:
+	    case IP_PROTOCOL_UDP:
 	      udp = (udp_header_t *) (inner_ip + 1);
 	      if (!it_fits (vm, b, udp, sizeof (*udp)))
 		{
@@ -3765,7 +3602,7 @@ nat_6t_flow_icmp_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 	      new_icmp_sum = ip_csum_fold (new_icmp_sum);
 	      icmp->checksum = new_icmp_sum;
 	      break;
-	    case NAT_PROTOCOL_TCP:
+	    case IP_PROTOCOL_TCP:
 	      tcp = (tcp_header_t *) (inner_ip + 1);
 	      if (!it_fits (vm, b, tcp, sizeof (*tcp)))
 		{
@@ -3786,7 +3623,7 @@ nat_6t_flow_icmp_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 	      new_icmp_sum = ip_csum_fold (new_icmp_sum);
 	      icmp->checksum = new_icmp_sum;
 	      break;
-	    case NAT_PROTOCOL_ICMP:
+	    case IP_PROTOCOL_ICMP:
 	      if (f->ops & NAT_FLOW_OP_ICMP_ID_REWRITE)
 		{
 		  icmp46_header_t *inner_icmp = ip4_next_header (inner_ip);
@@ -3825,7 +3662,7 @@ nat_6t_flow_icmp_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 static_always_inline nat_translation_error_e
 nat_6t_flow_buf_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 			   ip4_header_t *ip, nat_6t_flow_t *f,
-			   nat_protocol_t proto, int is_output_feature,
+			   ip_protocol_t proto, int is_output_feature,
 			   int is_i2o)
 {
   if (!is_output_feature && f->ops & NAT_FLOW_OP_TXFIB_REWRITE)
@@ -3833,7 +3670,7 @@ nat_6t_flow_buf_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
       vnet_buffer (b)->sw_if_index[VLIB_TX] = f->rewrite.fib_index;
     }
 
-  if (NAT_PROTOCOL_ICMP == proto)
+  if (IP_PROTOCOL_ICMP == proto)
     {
       if (ip->src_address.as_u32 != f->rewrite.saddr.as_u32)
 	{
@@ -3861,7 +3698,7 @@ nat_6t_flow_buf_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 nat_translation_error_e
 nat_6t_flow_buf_translate_i2o (vlib_main_t *vm, snat_main_t *sm,
 			       vlib_buffer_t *b, ip4_header_t *ip,
-			       nat_6t_flow_t *f, nat_protocol_t proto,
+			       nat_6t_flow_t *f, ip_protocol_t proto,
 			       int is_output_feature)
 {
   return nat_6t_flow_buf_translate (vm, sm, b, ip, f, proto, is_output_feature,
@@ -3871,7 +3708,7 @@ nat_6t_flow_buf_translate_i2o (vlib_main_t *vm, snat_main_t *sm,
 nat_translation_error_e
 nat_6t_flow_buf_translate_o2i (vlib_main_t *vm, snat_main_t *sm,
 			       vlib_buffer_t *b, ip4_header_t *ip,
-			       nat_6t_flow_t *f, nat_protocol_t proto,
+			       nat_6t_flow_t *f, ip_protocol_t proto,
 			       int is_output_feature)
 {
   return nat_6t_flow_buf_translate (vm, sm, b, ip, f, proto, is_output_feature,
@@ -3981,6 +3818,81 @@ format_nat_6t_flow (u8 *s, va_list *args)
   return s;
 }
 
+static inline void
+nat_syslog_nat44_sess (u32 ssubix, u32 sfibix, ip4_address_t *isaddr,
+		       u16 isport, ip4_address_t *xsaddr, u16 xsport,
+		       ip4_address_t *idaddr, u16 idport,
+		       ip4_address_t *xdaddr, u16 xdport, u8 proto, u8 is_add,
+		       u8 is_twicenat)
+{
+  syslog_msg_t syslog_msg;
+  fib_table_t *fib;
+
+  if (!syslog_is_enabled ())
+    return;
+
+  if (syslog_severity_filter_block (SADD_SDEL_SEVERITY))
+    return;
+
+  fib = fib_table_get (sfibix, FIB_PROTOCOL_IP4);
+
+  syslog_msg_init (&syslog_msg, NAT_FACILITY, SADD_SDEL_SEVERITY, NAT_APPNAME,
+		   is_add ? SADD_MSGID : SDEL_MSGID);
+
+  syslog_msg_sd_init (&syslog_msg, NSESS_SDID);
+  syslog_msg_add_sd_param (&syslog_msg, SSUBIX_SDPARAM_NAME, "%d", ssubix);
+  syslog_msg_add_sd_param (&syslog_msg, SVLAN_SDPARAM_NAME, "%d",
+			   fib->ft_table_id);
+  syslog_msg_add_sd_param (&syslog_msg, IATYP_SDPARAM_NAME, IATYP_IPV4);
+  syslog_msg_add_sd_param (&syslog_msg, ISADDR_SDPARAM_NAME, "%U",
+			   format_ip4_address, isaddr);
+  syslog_msg_add_sd_param (&syslog_msg, ISPORT_SDPARAM_NAME, "%d",
+			   clib_net_to_host_u16 (isport));
+  syslog_msg_add_sd_param (&syslog_msg, XATYP_SDPARAM_NAME, IATYP_IPV4);
+  syslog_msg_add_sd_param (&syslog_msg, XSADDR_SDPARAM_NAME, "%U",
+			   format_ip4_address, xsaddr);
+  syslog_msg_add_sd_param (&syslog_msg, XSPORT_SDPARAM_NAME, "%d",
+			   clib_net_to_host_u16 (xsport));
+  syslog_msg_add_sd_param (&syslog_msg, PROTO_SDPARAM_NAME, "%d", proto);
+  syslog_msg_add_sd_param (&syslog_msg, XDADDR_SDPARAM_NAME, "%U",
+			   format_ip4_address, xdaddr);
+  syslog_msg_add_sd_param (&syslog_msg, XDPORT_SDPARAM_NAME, "%d",
+			   clib_net_to_host_u16 (xdport));
+  if (is_twicenat)
+    {
+      syslog_msg_add_sd_param (&syslog_msg, IDADDR_SDPARAM_NAME, "%U",
+			       format_ip4_address, idaddr);
+      syslog_msg_add_sd_param (&syslog_msg, IDPORT_SDPARAM_NAME, "%d",
+			       clib_net_to_host_u16 (idport));
+    }
+
+  syslog_msg_send (&syslog_msg);
+}
+
+void
+nat_syslog_nat44_sadd (u32 ssubix, u32 sfibix, ip4_address_t *isaddr,
+		       u16 isport, ip4_address_t *idaddr, u16 idport,
+		       ip4_address_t *xsaddr, u16 xsport,
+		       ip4_address_t *xdaddr, u16 xdport, u8 proto,
+		       u8 is_twicenat)
+{
+  nat_syslog_nat44_sess (ssubix, sfibix, isaddr, isport, xsaddr, xsport,
+			 idaddr, idport, xdaddr, xdport, proto, 1,
+			 is_twicenat);
+}
+
+void
+nat_syslog_nat44_sdel (u32 ssubix, u32 sfibix, ip4_address_t *isaddr,
+		       u16 isport, ip4_address_t *idaddr, u16 idport,
+		       ip4_address_t *xsaddr, u16 xsport,
+		       ip4_address_t *xdaddr, u16 xdport, u8 proto,
+		       u8 is_twicenat)
+{
+  nat_syslog_nat44_sess (ssubix, sfibix, isaddr, isport, xsaddr, xsport,
+			 idaddr, idport, xdaddr, xdport, proto, 0,
+			 is_twicenat);
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/plugins/nat/nat44-ed/nat44_ed.h b/src/plugins/nat/nat44-ed/nat44_ed.h
index e2f5810f9b0..4665f7c0966 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed.h
+++ b/src/plugins/nat/nat44-ed/nat44_ed.h
@@ -39,6 +39,11 @@
 /* default number of worker handoff frame queue elements */
 #define NAT_FQ_NELTS_DEFAULT 64
 
+/* number of attempts to get a port for ED overloading algorithm, if rolling
+ * a dice this many times doesn't produce a free port, it's treated
+ * as if there were no free ports available to conserve resources */
+#define ED_PORT_ALLOC_ATTEMPTS (10)
+
 /* NAT buffer flags */
 #define SNAT_FLAG_HAIRPINNING (1 << 0)
 
@@ -172,7 +177,6 @@ typedef enum
 
 /* Session flags */
 #define SNAT_SESSION_FLAG_STATIC_MAPPING     (1 << 0)
-#define SNAT_SESSION_FLAG_UNKNOWN_PROTO	     (1 << 1)
 #define SNAT_SESSION_FLAG_LOAD_BALANCING     (1 << 2)
 #define SNAT_SESSION_FLAG_TWICE_NAT	     (1 << 3)
 #define SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT (1 << 4)
@@ -308,7 +312,7 @@ typedef CLIB_PACKED(struct
     u16 port;
   } in2out;
 
-  nat_protocol_t nat_proto;
+  ip_protocol_t proto;
 
   nat_6t_flow_t i2o;
   nat_6t_flow_t o2i;
@@ -356,12 +360,6 @@ typedef struct
 {
   ip4_address_t addr;
   u32 fib_index;
-#define _(N, i, n, s) \
-  u32 busy_##n##_ports; \
-  u32 * busy_##n##_ports_per_thread; \
-  u32 busy_##n##_port_refcounts[65535];
-  foreach_nat_protocol
-#undef _
 } snat_address_t;
 
 typedef struct
@@ -426,7 +424,7 @@ typedef struct
   u32 vrf_id;
   u32 fib_index;
   /* protocol */
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   /* 0 = disabled, otherwise client IP affinity sticky time in seconds */
   u32 affinity;
   /* worker threads used by backends/local host */
@@ -455,7 +453,7 @@ typedef struct
   u16 e_port;
   u32 sw_if_index;
   u32 vrf_id;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   u32 flags;
   int addr_only;
   int twice_nat;
@@ -500,15 +498,10 @@ u32 nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 
 /* Return worker thread index for given packet */
 /* NAT address and port allocation function */
-typedef int (nat_alloc_out_addr_and_port_function_t) (snat_address_t *
-						      addresses,
-						      u32 fib_index,
-						      u32 thread_index,
-						      nat_protocol_t proto,
-						      ip4_address_t * addr,
-						      u16 * port,
-						      u16 port_per_thread,
-						      u32 snat_thread_index);
+typedef int (nat_alloc_out_addr_and_port_function_t) (
+  snat_address_t *addresses, u32 fib_index, u32 thread_index,
+  ip_protocol_t proto, ip4_address_t *addr, u16 *port, u16 port_per_thread,
+  u32 snat_thread_index);
 
 typedef struct snat_main_s
 {
@@ -521,12 +514,6 @@ typedef struct snat_main_s
   /* Per thread data */
   snat_main_per_thread_data_t *per_thread_data;
 
-  /* Find a static mapping by local */
-  clib_bihash_8_8_t static_mapping_by_local;
-
-  /* Find a static mapping by external */
-  clib_bihash_8_8_t static_mapping_by_external;
-
   /* Static mapping pool */
   snat_static_mapping_t *static_mappings;
 
@@ -715,12 +702,8 @@ extern fib_source_t nat_fib_src_low;
 format_function_t format_snat_static_mapping;
 format_function_t format_snat_static_map_to_resolve;
 format_function_t format_snat_session;
-format_function_t format_snat_key;
 format_function_t format_static_mapping_key;
-format_function_t format_nat_protocol;
 format_function_t format_nat_addr_and_port_alloc_alg;
-/* unformat functions */
-unformat_function_t unformat_nat_protocol;
 
 /** \brief Check if SNAT session is created from static mapping.
     @param s SNAT session
@@ -732,16 +715,6 @@ nat44_ed_is_session_static (snat_session_t *s)
   return s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING;
 }
 
-/** \brief Check if SNAT session for unknown protocol.
-    @param s SNAT session
-    @return true if SNAT session for unknown protocol otherwise 0
-*/
-always_inline bool
-snat_is_unk_proto_session (snat_session_t *s)
-{
-  return s->flags & SNAT_SESSION_FLAG_UNKNOWN_PROTO;
-}
-
 /** \brief Check if NAT session is twice NAT.
     @param s NAT session
     @return true if NAT session is twice NAT
@@ -910,25 +883,25 @@ int nat44_ed_add_interface_address (u32 sw_if_index, u8 twice_nat);
 int nat44_ed_del_interface_address (u32 sw_if_index, u8 twice_nat);
 
 int nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
-				 u16 l_port, u16 e_port, nat_protocol_t proto,
+				 u16 l_port, u16 e_port, ip_protocol_t proto,
 				 u32 vrf_id, u32 sw_if_index, u32 flags,
 				 ip4_address_t pool_addr, u8 *tag);
 
 int nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
-				 u16 l_port, u16 e_port, nat_protocol_t proto,
+				 u16 l_port, u16 e_port, ip_protocol_t proto,
 				 u32 vrf_id, u32 sw_if_index, u32 flags);
 
 int nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
-				    nat_protocol_t proto,
+				    ip_protocol_t proto,
 				    nat44_lb_addr_port_t *locals, u32 flags,
 				    u8 *tag, u32 affinity);
 
 int nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
-				    nat_protocol_t proto, u32 flags);
+				    ip_protocol_t proto, u32 flags);
 
 int nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 					      ip4_address_t l_addr, u16 l_port,
-					      nat_protocol_t proto, u32 vrf_id,
+					      ip_protocol_t proto, u32 vrf_id,
 					      u8 probability, u8 is_add);
 
 /**
@@ -947,16 +920,8 @@ int nat44_ed_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
 			  ip4_address_t *eh_addr, u16 eh_port, u8 proto,
 			  u32 vrf_id, int is_in);
 
-/**
- * @brief Free NAT44 session data (lookup keys, external address port)
- *
- * @param sm           snat global configuration data
- * @param s            NAT session
- * @param thread_index thread index
- * @param is_ha        is HA event
- */
-void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
-			    u32 thread_index, u8 is_ha);
+void nat44_ed_free_session_data (snat_main_t *sm, snat_session_t *s,
+				 u32 thread_index, u8 is_ha);
 
 /**
  * @brief Set NAT44 session limit (session limit, vrf id)
@@ -976,19 +941,6 @@ int nat44_set_session_limit (u32 session_limit, u32 vrf_id);
  */
 int nat44_update_session_limit (u32 session_limit, u32 vrf_id);
 
-/**
- * @brief Free outside address and port pair
- *
- * @param addresses    vector of outside addresses
- * @param thread_index thread index
- * @param key          address, port and protocol
- */
-void
-snat_free_outside_address_and_port (snat_address_t * addresses,
-				    u32 thread_index,
-				    ip4_address_t * addr,
-				    u16 port, nat_protocol_t protocol);
-
 void expire_per_vrf_sessions (u32 fib_index);
 
 /**
@@ -1011,9 +963,9 @@ void expire_per_vrf_sessions (u32 fib_index);
  */
 int snat_static_mapping_match (
   vlib_main_t *vm, snat_main_t *sm, ip4_address_t match_addr, u16 match_port,
-  u32 match_fib_index, nat_protocol_t match_protocol,
+  u32 match_fib_index, ip_protocol_t match_protocol,
   ip4_address_t *mapping_addr, u16 *mapping_port, u32 *mapping_fib_index,
-  u8 by_external, u8 *is_addr_only, twice_nat_type_t *twice_nat,
+  int by_external, u8 *is_addr_only, twice_nat_type_t *twice_nat,
   lb_nat_type_t *lb, ip4_address_t *ext_host_addr, u8 *is_identity_nat,
   snat_static_mapping_t **out);
 
@@ -1060,11 +1012,11 @@ typedef enum
 
 nat_translation_error_e nat_6t_flow_buf_translate_i2o (
   vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
-  nat_6t_flow_t *f, nat_protocol_t proto, int is_output_feature);
+  nat_6t_flow_t *f, ip_protocol_t proto, int is_output_feature);
 
 nat_translation_error_e nat_6t_flow_buf_translate_o2i (
   vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
-  nat_6t_flow_t *f, nat_protocol_t proto, int is_output_feature);
+  nat_6t_flow_t *f, ip_protocol_t proto, int is_output_feature);
 
 void nat_6t_l3_l4_csum_calc (nat_6t_flow_t *f);
 
@@ -1072,6 +1024,26 @@ format_function_t format_nat_ed_translation_error;
 format_function_t format_nat_6t_flow;
 format_function_t format_ed_session_kvp;
 
+snat_static_mapping_t *nat44_ed_sm_i2o_lookup (snat_main_t *sm,
+					       ip4_address_t addr, u16 port,
+					       u32 fib_index, u8 proto);
+
+snat_static_mapping_t *nat44_ed_sm_o2i_lookup (snat_main_t *sm,
+					       ip4_address_t addr, u16 port,
+					       u32 fib_index, u8 proto);
+
+void nat_syslog_nat44_sadd (u32 ssubix, u32 sfibix, ip4_address_t *isaddr,
+			    u16 isport, ip4_address_t *idaddr, u16 idport,
+			    ip4_address_t *xsaddr, u16 xsport,
+			    ip4_address_t *xdaddr, u16 xdport, u8 proto,
+			    u8 is_twicenat);
+
+void nat_syslog_nat44_sdel (u32 ssubix, u32 sfibix, ip4_address_t *isaddr,
+			    u16 isport, ip4_address_t *idaddr, u16 idport,
+			    ip4_address_t *xsaddr, u16 xsport,
+			    ip4_address_t *xdaddr, u16 xdport, u8 proto,
+			    u8 is_twicenat);
+
 #endif /* __included_nat44_ed_h__ */
 /*
  * fd.io coding-style-patch-verification: ON
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_affinity.c b/src/plugins/nat/nat44-ed/nat44_ed_affinity.c
index 89f11c64ef3..178671c6b7e 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_affinity.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_affinity.c
@@ -37,10 +37,9 @@ format_affinity_kvp (u8 * s, va_list * args)
   k.as_u64[1] = v->key[1];
 
   s = format (s, "client %U backend %U:%d proto %U index %llu",
-	      format_ip4_address, &k.client_addr,
-	      format_ip4_address, &k.service_addr,
-	      clib_net_to_host_u16 (k.service_port),
-	      format_nat_protocol, k.proto);
+	      format_ip4_address, &k.client_addr, format_ip4_address,
+	      &k.service_addr, clib_net_to_host_u16 (k.service_port),
+	      format_ip_protocol, k.proto);
 
   return s;
 }
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_api.c b/src/plugins/nat/nat44-ed/nat44_ed_api.c
index ad00d11052b..d37c2855158 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_api.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_api.c
@@ -628,7 +628,7 @@ static void
   ip4_address_t l_addr, e_addr, pool_addr = { 0 };
   u32 sw_if_index, flags = 0, vrf_id;
   u16 l_port = 0, e_port = 0;
-  nat_protocol_t proto = 0;
+  ip_protocol_t proto = 0;
   u8 *tag = 0;
 
   memcpy (&l_addr.as_u8, mp->local_ip_address, 4);
@@ -641,7 +641,7 @@ static void
     {
       l_port = mp->local_port;
       e_port = mp->external_port;
-      proto = ip_proto_to_nat_proto (mp->protocol);
+      proto = mp->protocol;
     }
 
   if (mp->flags & NAT_API_IS_TWICE_NAT)
@@ -702,7 +702,7 @@ static void
   ip4_address_t l_addr, e_addr, pool_addr;
   u32 sw_if_index, flags = 0, vrf_id;
   u16 l_port = 0, e_port = 0;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   u8 *tag = 0;
 
   memcpy (&l_addr.as_u8, mp->local_ip_address, 4);
@@ -748,7 +748,7 @@ static void
       memcpy (&e_addr.as_u8, mp->external_ip_address, 4);
     }
 
-  proto = ip_proto_to_nat_proto (mp->protocol);
+  proto = mp->protocol;
   vrf_id = clib_net_to_host_u32 (mp->vrf_id);
 
   if (mp->is_add)
@@ -812,7 +812,7 @@ send_nat44_static_mapping_details (snat_static_mapping_t * m,
     }
   else
     {
-      rmp->protocol = nat_proto_to_ip_proto (m->proto);
+      rmp->protocol = m->proto;
       rmp->external_port = m->external_port;
       rmp->local_port = m->local_port;
     }
@@ -849,7 +849,7 @@ send_nat44_static_map_resolve_details (snat_static_map_resolve_t * m,
     }
   else
     {
-      rmp->protocol = nat_proto_to_ip_proto (m->proto);
+      rmp->protocol = m->proto;
       rmp->external_port = m->e_port;
       rmp->local_port = m->l_port;
     }
@@ -898,7 +898,7 @@ static void
 
   ip4_address_t addr, pool_addr = { 0 };
   u32 sw_if_index, flags, vrf_id;
-  nat_protocol_t proto = 0;
+  ip_protocol_t proto = 0;
   u16 port = 0;
   u8 *tag = 0;
 
@@ -911,7 +911,7 @@ static void
   else
     {
       port = mp->port;
-      proto = ip_proto_to_nat_proto (mp->protocol);
+      proto = mp->protocol;
     }
 
   sw_if_index = clib_net_to_host_u32 (mp->sw_if_index);
@@ -964,7 +964,7 @@ send_nat44_identity_mapping_details (snat_static_mapping_t * m, int index,
   rmp->port = m->local_port;
   rmp->sw_if_index = ~0;
   rmp->vrf_id = htonl (local->vrf_id);
-  rmp->protocol = nat_proto_to_ip_proto (m->proto);
+  rmp->protocol = m->proto;
   rmp->context = context;
   if (m->tag)
     strncpy ((char *) rmp->tag, (char *) m->tag, vec_len (m->tag));
@@ -991,7 +991,7 @@ send_nat44_identity_map_resolve_details (snat_static_map_resolve_t * m,
   rmp->port = m->l_port;
   rmp->sw_if_index = htonl (m->sw_if_index);
   rmp->vrf_id = htonl (m->vrf_id);
-  rmp->protocol = nat_proto_to_ip_proto (m->proto);
+  rmp->protocol = m->proto;
   rmp->context = context;
   if (m->tag)
     strncpy ((char *) rmp->tag, (char *) m->tag, vec_len (m->tag));
@@ -1140,7 +1140,7 @@ vl_api_nat44_add_del_lb_static_mapping_t_handler (
   vl_api_nat44_add_del_lb_static_mapping_reply_t *rmp;
   nat44_lb_addr_port_t *locals = 0;
   ip4_address_t e_addr;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   u32 flags = 0;
   u8 *tag = 0;
   int rv = 0;
@@ -1148,7 +1148,7 @@ vl_api_nat44_add_del_lb_static_mapping_t_handler (
   locals = unformat_nat44_lb_addr_port (mp->locals,
 					clib_net_to_host_u32 (mp->local_num));
   clib_memcpy (&e_addr, mp->external_addr, 4);
-  proto = ip_proto_to_nat_proto (mp->protocol);
+  proto = mp->protocol;
 
   if (mp->flags & NAT_API_IS_TWICE_NAT)
     {
@@ -1193,11 +1193,11 @@ vl_api_nat44_lb_static_mapping_add_del_local_t_handler (
   vl_api_nat44_lb_static_mapping_add_del_local_reply_t *rmp;
   int rv = 0;
   ip4_address_t e_addr, l_addr;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
 
   clib_memcpy (&e_addr, mp->external_addr, 4);
   clib_memcpy (&l_addr, mp->local.addr, 4);
-  proto = ip_proto_to_nat_proto (mp->protocol);
+  proto = mp->protocol;
 
   rv = nat44_ed_add_del_lb_static_mapping_local (
     e_addr, mp->external_port, l_addr, mp->local.port, proto,
@@ -1225,7 +1225,7 @@ send_nat44_lb_static_mapping_details (snat_static_mapping_t *m,
 
   clib_memcpy (rmp->external_addr, &(m->external_addr), 4);
   rmp->external_port = m->external_port;
-  rmp->protocol = nat_proto_to_ip_proto (m->proto);
+  rmp->protocol = m->proto;
   rmp->context = context;
 
   if (is_sm_self_twice_nat (m->flags))
@@ -1740,25 +1740,16 @@ send_nat44_user_session_details (snat_session_t * s,
   rmp->total_bytes = clib_host_to_net_u64 (s->total_bytes);
   rmp->total_pkts = ntohl (s->total_pkts);
   rmp->context = context;
-  if (snat_is_unk_proto_session (s))
-    {
-      rmp->outside_port = 0;
-      rmp->inside_port = 0;
-      rmp->protocol = ntohs (s->in2out.port);
-    }
-  else
+  rmp->outside_port = s->out2in.port;
+  rmp->inside_port = s->in2out.port;
+  rmp->protocol = ntohs (s->proto);
+  clib_memcpy (rmp->ext_host_address, &s->ext_host_addr, 4);
+  rmp->ext_host_port = s->ext_host_port;
+  if (nat44_ed_is_twice_nat_session (s))
     {
-      rmp->outside_port = s->out2in.port;
-      rmp->inside_port = s->in2out.port;
-      rmp->protocol = ntohs (nat_proto_to_ip_proto (s->nat_proto));
+      clib_memcpy (rmp->ext_host_nat_address, &s->ext_host_nat_addr, 4);
+      rmp->ext_host_nat_port = s->ext_host_nat_port;
     }
-      clib_memcpy (rmp->ext_host_address, &s->ext_host_addr, 4);
-      rmp->ext_host_port = s->ext_host_port;
-      if (nat44_ed_is_twice_nat_session (s))
-	{
-	  clib_memcpy (rmp->ext_host_nat_address, &s->ext_host_nat_addr, 4);
-	  rmp->ext_host_nat_port = s->ext_host_nat_port;
-	}
 
   vl_api_send_msg (reg, (u8 *) rmp);
 }
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_classify.c b/src/plugins/nat/nat44-ed/nat44_ed_classify.c
index 5a9f4e42657..229cf3669e6 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_classify.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_classify.c
@@ -98,7 +98,6 @@ nat44_handoff_classify_node_fn_inline (vlib_main_t * vm,
 	  u32 next0 = NAT_NEXT_IN2OUT_CLASSIFY;
 	  ip4_header_t *ip0;
 	  snat_address_t *ap;
-	  clib_bihash_kv_8_8_t kv0, value0;
 
 	  /* speculatively enqueue b0 to the current next frame */
 	  bi0 = from[0];
@@ -122,23 +121,19 @@ nat44_handoff_classify_node_fn_inline (vlib_main_t * vm,
 
 	  if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
 	    {
-	      init_nat_k (&kv0, ip0->dst_address, 0, 0, 0);
 	      /* try to classify the fragment based on IP header alone */
-	      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external,
-					   &kv0, &value0))
+	      m = nat44_ed_sm_o2i_lookup (sm, ip0->dst_address, 0, 0, 0);
+	      if (m)
 		{
-		  m = pool_elt_at_index (sm->static_mappings, value0.value);
 		  if (m->local_addr.as_u32 != m->external_addr.as_u32)
 		    next0 = NAT_NEXT_OUT2IN_CLASSIFY;
 		  goto enqueue0;
 		}
-	      init_nat_k (&kv0, ip0->dst_address,
-			  vnet_buffer (b0)->ip.reass.l4_dst_port, 0,
-			  ip_proto_to_nat_proto (ip0->protocol));
-	      if (!clib_bihash_search_8_8
-		  (&sm->static_mapping_by_external, &kv0, &value0))
+	      m = nat44_ed_sm_o2i_lookup (
+		sm, ip0->dst_address, vnet_buffer (b0)->ip.reass.l4_dst_port,
+		0, ip0->protocol);
+	      if (m)
 		{
-		  m = pool_elt_at_index (sm->static_mappings, value0.value);
 		  if (m->local_addr.as_u32 != m->external_addr.as_u32)
 		    next0 = NAT_NEXT_OUT2IN_CLASSIFY;
 		}
@@ -202,7 +197,6 @@ nat44_ed_classify_node_fn_inline (vlib_main_t * vm,
 	  u32 sw_if_index0, rx_fib_index0;
 	  ip4_header_t *ip0;
 	  snat_address_t *ap;
-	  clib_bihash_kv_8_8_t kv0, value0;
 	  clib_bihash_kv_16_8_t ed_kv0, ed_value0;
 
 	  /* speculatively enqueue b0 to the current next frame */
@@ -227,11 +221,11 @@ nat44_ed_classify_node_fn_inline (vlib_main_t * vm,
 	      rx_fib_index0 =
 		fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
 						     sw_if_index0);
-	      init_ed_k (&ed_kv0, ip0->src_address,
+	      init_ed_k (&ed_kv0, ip0->src_address.as_u32,
 			 vnet_buffer (b0)->ip.reass.l4_src_port,
-			 ip0->dst_address,
-			 vnet_buffer (b0)->ip.reass.l4_dst_port,
-			 rx_fib_index0, ip0->protocol);
+			 ip0->dst_address.as_u32,
+			 vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
+			 ip0->protocol);
 	      /* process whole packet */
 	      if (!clib_bihash_search_16_8 (&sm->flow_hash, &ed_kv0,
 					    &ed_value0))
@@ -272,23 +266,19 @@ nat44_ed_classify_node_fn_inline (vlib_main_t * vm,
 
 	  if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
 	    {
-	      init_nat_k (&kv0, ip0->dst_address, 0, 0, 0);
 	      /* try to classify the fragment based on IP header alone */
-	      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external,
-					   &kv0, &value0))
+	      m = nat44_ed_sm_o2i_lookup (sm, ip0->dst_address, 0, 0, 0);
+	      if (m)
 		{
-		  m = pool_elt_at_index (sm->static_mappings, value0.value);
 		  if (m->local_addr.as_u32 != m->external_addr.as_u32)
 		    next0 = NAT_NEXT_OUT2IN_ED_FAST_PATH;
 		  goto enqueue0;
 		}
-	      init_nat_k (&kv0, ip0->dst_address,
-			  vnet_buffer (b0)->ip.reass.l4_dst_port, 0,
-			  ip_proto_to_nat_proto (ip0->protocol));
-	      if (!clib_bihash_search_8_8
-		  (&sm->static_mapping_by_external, &kv0, &value0))
+	      m = nat44_ed_sm_o2i_lookup (
+		sm, ip0->dst_address, vnet_buffer (b0)->ip.reass.l4_dst_port,
+		0, ip0->protocol);
+	      if (m)
 		{
-		  m = pool_elt_at_index (sm->static_mappings, value0.value);
 		  if (m->local_addr.as_u32 != m->external_addr.as_u32)
 		    next0 = NAT_NEXT_OUT2IN_ED_FAST_PATH;
 		}
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_cli.c b/src/plugins/nat/nat44-ed/nat44_ed_cli.c
index 413c7959962..5ab14a6729a 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_cli.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_cli.c
@@ -283,12 +283,7 @@ nat44_show_hash_command_fn (vlib_main_t * vm, unformat_input_t * input,
   else if (unformat (input, "verbose"))
     verbose = 2;
 
-  vlib_cli_output (vm, "%U", format_bihash_8_8, &sm->static_mapping_by_local,
-		   verbose);
-  vlib_cli_output (vm, "%U",
-		   format_bihash_8_8, &sm->static_mapping_by_external,
-		   verbose);
-      vlib_cli_output (vm, "%U", format_bihash_16_8, &sm->flow_hash, verbose);
+  vlib_cli_output (vm, "%U", format_bihash_16_8, &sm->flow_hash, verbose);
   vec_foreach_index (i, sm->per_thread_data)
   {
     vlib_cli_output (vm, "-------- thread %d %s --------\n",
@@ -296,8 +291,7 @@ nat44_show_hash_command_fn (vlib_main_t * vm, unformat_input_t * input,
     vlib_cli_output (vm, "%U", format_bihash_16_8, &sm->flow_hash, verbose);
   }
 
-      vlib_cli_output (vm, "%U", format_bihash_16_8, &nam->affinity_hash,
-		       verbose);
+  vlib_cli_output (vm, "%U", format_bihash_16_8, &nam->affinity_hash, verbose);
 
   vlib_cli_output (vm, "-------- hash table parameters --------\n");
   vlib_cli_output (vm, "translation buckets: %u", sm->translation_buckets);
@@ -502,6 +496,7 @@ nat44_show_summary_command_fn (vlib_main_t * vm, unformat_input_t * input,
   u32 udp_sessions = 0;
   u32 tcp_sessions = 0;
   u32 icmp_sessions = 0;
+  u32 other_sessions = 0;
 
   u32 timed_out = 0;
   u32 transitory = 0;
@@ -526,40 +521,42 @@ nat44_show_summary_command_fn (vlib_main_t * vm, unformat_input_t * input,
             if (now >= sess_timeout_time)
               timed_out++;
 
-            switch (s->nat_proto)
-              {
-              case NAT_PROTOCOL_ICMP:
-                icmp_sessions++;
-                break;
-              case NAT_PROTOCOL_TCP:
-                tcp_sessions++;
-                if (s->state)
-                  {
-                    if (s->tcp_closed_timestamp)
-                      {
-                        if (now >= s->tcp_closed_timestamp)
-                          {
-                            ++transitory_closed;
-                          }
-                        else
-                          {
-                            ++transitory_wait_closed;
-                          }
-                      }
-                    transitory++;
-                  }
-                else
-                  established++;
-                break;
-              case NAT_PROTOCOL_UDP:
-              default:
-                udp_sessions++;
-                break;
-              }
-          }
-          nat44_show_lru_summary (vm, tsm, now, sess_timeout_time);
-          count += pool_elts (tsm->sessions);
-        }
+	    switch (s->proto)
+	      {
+	      case IP_PROTOCOL_ICMP:
+		icmp_sessions++;
+		break;
+	      case IP_PROTOCOL_TCP:
+		tcp_sessions++;
+		if (s->state)
+		  {
+		    if (s->tcp_closed_timestamp)
+		      {
+			if (now >= s->tcp_closed_timestamp)
+			  {
+			    ++transitory_closed;
+			  }
+			else
+			  {
+			    ++transitory_wait_closed;
+			  }
+		      }
+		    transitory++;
+		  }
+		else
+		  established++;
+		break;
+	      case IP_PROTOCOL_UDP:
+		udp_sessions++;
+		break;
+	      default:
+		++other_sessions;
+		break;
+	      }
+	   }
+	  nat44_show_lru_summary (vm, tsm, now, sess_timeout_time);
+	  count += pool_elts (tsm->sessions);
+	}
     }
   else
     {
@@ -571,36 +568,38 @@ nat44_show_summary_command_fn (vlib_main_t * vm, unformat_input_t * input,
         if (now >= sess_timeout_time)
           timed_out++;
 
-        switch (s->nat_proto)
-          {
-          case NAT_PROTOCOL_ICMP:
-            icmp_sessions++;
-            break;
-          case NAT_PROTOCOL_TCP:
-            tcp_sessions++;
-            if (s->state)
-              {
-                if (s->tcp_closed_timestamp)
-                  {
-                    if (now >= s->tcp_closed_timestamp)
-                      {
-                        ++transitory_closed;
-                      }
-                    else
-                      {
-                        ++transitory_wait_closed;
-                      }
-                  }
-                transitory++;
-              }
-            else
-              established++;
-            break;
-          case NAT_PROTOCOL_UDP:
-          default:
-            udp_sessions++;
-            break;
-          }
+	switch (s->proto)
+	  {
+	  case IP_PROTOCOL_ICMP:
+	    icmp_sessions++;
+	    break;
+	  case IP_PROTOCOL_TCP:
+	    tcp_sessions++;
+	    if (s->state)
+	      {
+		if (s->tcp_closed_timestamp)
+		  {
+		    if (now >= s->tcp_closed_timestamp)
+		      {
+			++transitory_closed;
+		      }
+		    else
+		      {
+			++transitory_wait_closed;
+		      }
+		  }
+		transitory++;
+	      }
+	    else
+	      established++;
+	    break;
+	  case IP_PROTOCOL_UDP:
+	    udp_sessions++;
+	    break;
+	  default:
+	    ++other_sessions;
+	    break;
+	  }
       }
       nat44_show_lru_summary (vm, tsm, now, sess_timeout_time);
       count = pool_elts (tsm->sessions);
@@ -617,6 +616,7 @@ nat44_show_summary_command_fn (vlib_main_t * vm, unformat_input_t * input,
 		   transitory_closed);
   vlib_cli_output (vm, "total udp sessions: %u", udp_sessions);
   vlib_cli_output (vm, "total icmp sessions: %u", icmp_sessions);
+  vlib_cli_output (vm, "total other sessions: %u", other_sessions);
   return 0;
 }
 
@@ -636,10 +636,6 @@ nat44_show_addresses_command_fn (vlib_main_t * vm, unformat_input_t * input,
             fib_table_get(ap->fib_index, FIB_PROTOCOL_IP4)->ft_table_id);
       else
         vlib_cli_output (vm, "  tenant VRF independent");
-    #define _(N, i, n, s) \
-      vlib_cli_output (vm, "  %d busy %s ports", ap->busy_##n##_ports, s);
-      foreach_nat_protocol
-    #undef _
     }
   vlib_cli_output (vm, "NAT44 twice-nat pool addresses:");
   vec_foreach (ap, sm->twice_nat_addresses)
@@ -650,10 +646,6 @@ nat44_show_addresses_command_fn (vlib_main_t * vm, unformat_input_t * input,
             fib_table_get(ap->fib_index, FIB_PROTOCOL_IP4)->ft_table_id);
       else
         vlib_cli_output (vm, "  tenant VRF independent");
-    #define _(N, i, n, s) \
-      vlib_cli_output (vm, "  %d busy %s ports", ap->busy_##n##_ports, s);
-      foreach_nat_protocol
-    #undef _
     }
   return 0;
 }
@@ -837,14 +829,13 @@ add_static_mapping_command_fn (vlib_main_t * vm,
   unformat_input_t _line_input, *line_input = &_line_input;
   vnet_main_t *vnm = vnet_get_main ();
   clib_error_t *error = 0;
-  int rv;
-
-  nat_protocol_t proto = NAT_PROTOCOL_OTHER;
   ip4_address_t l_addr, e_addr, pool_addr;
   u32 l_port = 0, e_port = 0, vrf_id = ~0;
   u8 l_port_set = 0, e_port_set = 0;
-  u32 sw_if_index, flags = 0;
-  int is_add = 1;
+  int is_add = 1, rv;
+  u32 flags = 0;
+  u32 sw_if_index = ~0;
+  ip_protocol_t proto = 0;
 
   if (!unformat_user (input, unformat_line_input, line_input))
     return clib_error_return (0, NAT44_ED_EXPECTED_ARGUMENT);
@@ -886,7 +877,7 @@ add_static_mapping_command_fn (vlib_main_t * vm,
 	}
       else if (unformat (line_input, "vrf %u", &vrf_id))
 	;
-      else if (unformat (line_input, "%U", unformat_nat_protocol, &proto))
+      else if (unformat (line_input, "%U", unformat_ip_protocol, &proto))
 	;
       else if (unformat (line_input, "self-twice-nat"))
 	{
@@ -983,7 +974,7 @@ add_identity_mapping_command_fn (vlib_main_t * vm,
 
   int rv, is_add = 1, port_set = 0;
   u32 sw_if_index, port, flags, vrf_id = ~0;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   ip4_address_t addr;
 
   flags = NAT_SM_FLAG_IDENTITY_NAT;
@@ -1003,7 +994,7 @@ add_identity_mapping_command_fn (vlib_main_t * vm,
 	}
       else if (unformat (line_input, "vrf %u", &vrf_id))
 	;
-      else if (unformat (line_input, "%U %u", unformat_nat_protocol, &proto,
+      else if (unformat (line_input, "%U %u", unformat_ip_protocol, &proto,
 			 &port))
 	{
 	  port_set = 1;
@@ -1080,7 +1071,7 @@ add_lb_static_mapping_command_fn (vlib_main_t * vm,
   ip4_address_t l_addr, e_addr;
   u32 l_port = 0, e_port = 0, vrf_id = 0, probability = 0, affinity = 0;
   u8 proto_set = 0;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   nat44_lb_addr_port_t *locals = 0, local;
   int rv, is_add = 1;
   u32 flags = 0;
@@ -1114,7 +1105,7 @@ add_lb_static_mapping_command_fn (vlib_main_t * vm,
       else if (unformat (line_input, "external %U:%u", unformat_ip4_address,
 			 &e_addr, &e_port))
 	;
-      else if (unformat (line_input, "protocol %U", unformat_nat_protocol,
+      else if (unformat (line_input, "protocol %U", unformat_ip_protocol,
 			 &proto))
 	{
 	  proto_set = 1;
@@ -1202,7 +1193,7 @@ add_lb_backend_command_fn (vlib_main_t * vm,
   u32 l_port = 0, e_port = 0, vrf_id = 0, probability = 0;
   int is_add = 1;
   int rv;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   u8 proto_set = 0;
 
   /* Get a line of input. */
@@ -1221,7 +1212,7 @@ add_lb_backend_command_fn (vlib_main_t * vm,
       else if (unformat (line_input, "external %U:%u", unformat_ip4_address,
 			 &e_addr, &e_port))
 	;
-      else if (unformat (line_input, "protocol %U", unformat_nat_protocol,
+      else if (unformat (line_input, "protocol %U", unformat_ip_protocol,
 			 &proto))
 	proto_set = 1;
       else if (unformat (line_input, "del"))
@@ -1547,7 +1538,7 @@ nat44_del_session_command_fn (vlib_main_t * vm,
   u32 port = 0, eh_port = 0, vrf_id = sm->outside_vrf_id;
   clib_error_t *error = 0;
   ip4_address_t addr, eh_addr;
-  nat_protocol_t proto;
+  ip_protocol_t proto;
   int is_in = 0;
   int rv;
 
@@ -1556,9 +1547,8 @@ nat44_del_session_command_fn (vlib_main_t * vm,
 
   while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
     {
-      if (unformat
-	  (line_input, "%U:%u %U", unformat_ip4_address, &addr, &port,
-	   unformat_nat_protocol, &proto))
+      if (unformat (line_input, "%U:%u %U", unformat_ip4_address, &addr, &port,
+		    unformat_ip_protocol, &proto))
 	;
       else if (unformat (line_input, "in"))
 	{
@@ -1584,8 +1574,8 @@ nat44_del_session_command_fn (vlib_main_t * vm,
     }
 
   rv = nat44_ed_del_session (sm, &addr, clib_host_to_net_u16 (port), &eh_addr,
-			     clib_host_to_net_u16 (eh_port),
-			     nat_proto_to_ip_proto (proto), vrf_id, is_in);
+			     clib_host_to_net_u16 (eh_port), proto, vrf_id,
+			     is_in);
 
   switch (rv)
     {
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_format.c b/src/plugins/nat/nat44-ed/nat44_ed_format.c
index 442f6ad3d7a..5eb683d888e 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_format.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_format.c
@@ -20,39 +20,6 @@
 #include <nat/nat44-ed/nat44_ed.h>
 #include <nat/nat44-ed/nat44_ed_inlines.h>
 
-uword
-unformat_nat_protocol (unformat_input_t * input, va_list * args)
-{
-  u32 *r = va_arg (*args, u32 *);
-
-  if (0);
-#define _(N, i, n, s) else if (unformat (input, s)) *r = NAT_PROTOCOL_##N;
-  foreach_nat_protocol
-#undef _
-    else
-    return 0;
-  return 1;
-}
-
-u8 *
-format_nat_protocol (u8 * s, va_list * args)
-{
-  u32 i = va_arg (*args, u32);
-  u8 *t = 0;
-
-  switch (i)
-    {
-#define _(N, j, n, str) case NAT_PROTOCOL_##N: t = (u8 *) str; break;
-      foreach_nat_protocol
-#undef _
-    default:
-      s = format (s, "unknown");
-      return s;
-    }
-  s = format (s, "%s", t);
-  return s;
-}
-
 u8 *
 format_nat_addr_and_port_alloc_alg (u8 * s, va_list * args)
 {
@@ -73,25 +40,6 @@ format_nat_addr_and_port_alloc_alg (u8 * s, va_list * args)
 }
 
 u8 *
-format_snat_key (u8 * s, va_list * args)
-{
-  u64 key = va_arg (*args, u64);
-
-  ip4_address_t addr;
-  u16 port;
-  nat_protocol_t protocol;
-  u32 fib_index;
-
-  split_nat_key (key, &addr, &port, &fib_index, &protocol);
-
-  s = format (s, "%U proto %U port %d fib %d",
-	      format_ip4_address, &addr,
-	      format_nat_protocol, protocol,
-	      clib_net_to_host_u16 (port), fib_index);
-  return s;
-}
-
-u8 *
 format_snat_session_state (u8 * s, va_list * args)
 {
   u32 i = va_arg (*args, u32);
@@ -116,7 +64,7 @@ format_snat_session (u8 * s, va_list * args)
     va_arg (*args, snat_main_per_thread_data_t *);
   snat_session_t *sess = va_arg (*args, snat_session_t *);
 
-  if (snat_is_unk_proto_session (sess))
+  if (nat44_ed_is_unk_proto (sess->proto))
     {
       s = format (s, "  i2o %U proto %u fib %u\n",
 		  format_ip4_address, &sess->in2out.addr,
@@ -127,14 +75,13 @@ format_snat_session (u8 * s, va_list * args)
     }
   else
     {
-      s = format (s, "  i2o %U proto %U port %d fib %d\n",
-		  format_ip4_address, &sess->in2out.addr,
-		  format_nat_protocol, sess->nat_proto,
+      s = format (s, "  i2o %U proto %U port %d fib %d\n", format_ip4_address,
+		  &sess->in2out.addr, format_ip_protocol, sess->proto,
 		  clib_net_to_host_u16 (sess->in2out.port),
 		  sess->in2out.fib_index);
       s = format (s, "    o2i %U proto %U port %d fib %d\n",
-		  format_ip4_address, &sess->out2in.addr, format_nat_protocol,
-		  sess->nat_proto, clib_net_to_host_u16 (sess->out2in.port),
+		  format_ip4_address, &sess->out2in.addr, format_ip_protocol,
+		  sess->proto, clib_net_to_host_u16 (sess->out2in.port),
 		  sess->out2in.fib_index);
     }
   if (nat44_ed_is_twice_nat_session (sess))
@@ -183,9 +130,8 @@ format_snat_static_mapping (u8 * s, va_list * args)
 	s = format (s, "identity mapping %U",
 		    format_ip4_address, &m->local_addr);
       else
-	s = format (s, "identity mapping %U %U:%d",
-		    format_nat_protocol, m->proto,
-		    format_ip4_address, &m->local_addr,
+	s = format (s, "identity mapping %U %U:%d", format_ip_protocol,
+		    m->proto, format_ip4_address, &m->local_addr,
 		    clib_net_to_host_u16 (m->local_port));
 
       pool_foreach (local, m->locals)
@@ -209,8 +155,8 @@ format_snat_static_mapping (u8 * s, va_list * args)
       if (is_sm_lb (m->flags))
 	{
 	  s =
-	    format (s, "%U external %U:%d %s %s", format_nat_protocol,
-		    m->proto, format_ip4_address, &m->external_addr,
+	    format (s, "%U external %U:%d %s %s", format_ip_protocol, m->proto,
+		    format_ip4_address, &m->external_addr,
 		    clib_net_to_host_u16 (m->external_port),
 		    is_sm_twice_nat (m->flags) ?
 		      "twice-nat" :
@@ -227,7 +173,7 @@ format_snat_static_mapping (u8 * s, va_list * args)
 	}
       else
 	s = format (s, "%U local %U:%d external %U:%d vrf %d %s %s",
-		    format_nat_protocol, m->proto, format_ip4_address,
+		    format_ip_protocol, m->proto, format_ip4_address,
 		    &m->local_addr, clib_net_to_host_u16 (m->local_port),
 		    format_ip4_address, &m->external_addr,
 		    clib_net_to_host_u16 (m->external_port), m->vrf_id,
@@ -250,12 +196,11 @@ format_snat_static_map_to_resolve (u8 * s, va_list * args)
 		format_ip4_address, &m->l_addr,
 		format_vnet_sw_if_index_name, vnm, m->sw_if_index, m->vrf_id);
   else
-    s = format (s, "%U local %U:%d external %U:%d vrf %d",
-		format_nat_protocol, m->proto,
-		format_ip4_address, &m->l_addr,
-		clib_net_to_host_u16 (m->l_port),
-		format_vnet_sw_if_index_name, vnm, m->sw_if_index,
-		clib_net_to_host_u16 (m->e_port), m->vrf_id);
+    s = format (s, "%U local %U:%d external %U:%d vrf %d", format_ip_protocol,
+		m->proto, format_ip4_address, &m->l_addr,
+		clib_net_to_host_u16 (m->l_port), format_vnet_sw_if_index_name,
+		vnm, m->sw_if_index, clib_net_to_host_u16 (m->e_port),
+		m->vrf_id);
 
   return s;
 }
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_in2out.c b/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
index 0e330e17b36..73dacce57e6 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
@@ -25,18 +25,12 @@
 #include <vnet/udp/udp_local.h>
 #include <vppinfra/error.h>
 
-#include <nat/lib/nat_syslog.h>
 #include <nat/lib/nat_inlines.h>
 #include <nat/lib/ipfix_logging.h>
 
 #include <nat/nat44-ed/nat44_ed.h>
 #include <nat/nat44-ed/nat44_ed_inlines.h>
 
-/* number of attempts to get a port for ED overloading algorithm, if rolling
- * a dice this many times doesn't produce a free port, it's treated
- * as if there were no free ports available to conserve resources */
-#define ED_PORT_ALLOC_ATTEMPTS (10)
-
 static char *nat_in2out_ed_error_strings[] = {
 #define _(sym,string) string,
   foreach_nat_in2out_ed_error
@@ -166,7 +160,7 @@ snat_not_translate_fast (snat_main_t *sm, vlib_node_runtime_t *node,
 
 static int
 nat_ed_alloc_addr_and_port_with_snat_address (
-  snat_main_t *sm, u32 nat_proto, u32 thread_index, snat_address_t *a,
+  snat_main_t *sm, u8 proto, u32 thread_index, snat_address_t *a,
   u16 port_per_thread, u32 snat_thread_index, snat_session_t *s,
   ip4_address_t *outside_addr, u16 *outside_port)
 {
@@ -187,27 +181,13 @@ nat_ed_alloc_addr_and_port_with_snat_address (
   u16 attempts = ED_PORT_ALLOC_ATTEMPTS;
   do
     {
-      if (NAT_PROTOCOL_ICMP == nat_proto)
+      if (IP_PROTOCOL_ICMP == proto)
 	{
 	  s->o2i.match.sport = clib_host_to_net_u16 (port);
 	}
       s->o2i.match.dport = clib_host_to_net_u16 (port);
       if (0 == nat_ed_ses_o2i_flow_hash_add_del (sm, thread_index, s, 2))
 	{
-#define _(N, i, n, s)                                                         \
-  case NAT_PROTOCOL_##N:                                                      \
-    ++a->busy_##n##_port_refcounts[port];                                     \
-    a->busy_##n##_ports_per_thread[thread_index]++;                           \
-    a->busy_##n##_ports++;                                                    \
-    break;
-	  switch (nat_proto)
-	    {
-	      foreach_nat_protocol;
-	    default:
-	      nat_elog_info (sm, "unknown protocol");
-	      return 1;
-	    }
-#undef _
 	  *outside_addr = a->addr;
 	  *outside_port = clib_host_to_net_u16 (port);
 	  return 0;
@@ -223,9 +203,8 @@ nat_ed_alloc_addr_and_port_with_snat_address (
 static int
 nat_ed_alloc_addr_and_port (snat_main_t *sm, u32 rx_fib_index, u32 nat_proto,
 			    u32 thread_index, ip4_address_t s_addr,
-			    u16 port_per_thread, u32 snat_thread_index,
-			    snat_session_t *s, ip4_address_t *outside_addr,
-			    u16 *outside_port)
+			    u32 snat_thread_index, snat_session_t *s,
+			    ip4_address_t *outside_addr, u16 *outside_port)
 {
   int i;
   snat_address_t *a, *ga = 0;
@@ -240,7 +219,7 @@ nat_ed_alloc_addr_and_port (snat_main_t *sm, u32 rx_fib_index, u32 nat_proto,
 	  if (a->fib_index == rx_fib_index)
 	    {
 	      return nat_ed_alloc_addr_and_port_with_snat_address (
-		sm, nat_proto, thread_index, a, port_per_thread,
+		sm, nat_proto, thread_index, a, sm->port_per_thread,
 		snat_thread_index, s, outside_addr, outside_port);
 	    }
 	  else if (a->fib_index == ~0)
@@ -255,7 +234,7 @@ nat_ed_alloc_addr_and_port (snat_main_t *sm, u32 rx_fib_index, u32 nat_proto,
 	  if (a->fib_index == rx_fib_index)
 	    {
 	      return nat_ed_alloc_addr_and_port_with_snat_address (
-		sm, nat_proto, thread_index, a, port_per_thread,
+		sm, nat_proto, thread_index, a, sm->port_per_thread,
 		snat_thread_index, s, outside_addr, outside_port);
 	    }
 	  else if (a->fib_index == ~0)
@@ -267,8 +246,8 @@ nat_ed_alloc_addr_and_port (snat_main_t *sm, u32 rx_fib_index, u32 nat_proto,
       if (ga)
 	{
 	  return nat_ed_alloc_addr_and_port_with_snat_address (
-	    sm, nat_proto, thread_index, a, port_per_thread, snat_thread_index,
-	    s, outside_addr, outside_port);
+	    sm, nat_proto, thread_index, a, sm->port_per_thread,
+	    snat_thread_index, s, outside_addr, outside_port);
 	}
     }
   /* Totally out of translations to use... */
@@ -304,23 +283,18 @@ nat_outside_fib_index_lookup (snat_main_t * sm, ip4_address_t addr)
 
 static_always_inline int
 nat44_ed_external_sm_lookup (snat_main_t *sm, ip4_address_t match_addr,
-			     u16 match_port, nat_protocol_t match_protocol,
-			     u32 match_fib_index, ip4_address_t *daddr,
-			     u16 *dport)
+			     u16 match_port, ip_protocol_t match_protocol,
+			     ip4_address_t *daddr, u16 *dport)
 {
-  clib_bihash_kv_8_8_t kv, value;
-  init_nat_k (&kv, match_addr, match_port, match_fib_index, match_protocol);
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+  snat_static_mapping_t *m =
+    nat44_ed_sm_o2i_lookup (sm, match_addr, match_port, 0, match_protocol);
+  if (!m)
     {
       /* Try address only mapping */
-      init_nat_k (&kv, match_addr, 0, 0, 0);
-      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
-				  &value))
+      m = nat44_ed_sm_o2i_lookup (sm, match_addr, 0, 0, 0);
+      if (!m)
 	return 0;
     }
-
-  snat_static_mapping_t *m =
-    pool_elt_at_index (sm->static_mappings, value.value);
   *daddr = m->local_addr;
   if (dport)
     {
@@ -343,7 +317,6 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
   u32 outside_fib_index;
   u8 is_identity_nat = 0;
 
-  u32 nat_proto = ip_proto_to_nat_proto (proto);
   snat_session_t *s = NULL;
   lb_nat_type_t lb = 0;
   ip4_address_t daddr = r_addr;
@@ -382,9 +355,9 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
   u32 sm_fib_index;
   /* First try to match static mapping by local address and port */
   int is_sm;
-  if (snat_static_mapping_match (vm, sm, l_addr, l_port, rx_fib_index,
-				 nat_proto, &sm_addr, &sm_port, &sm_fib_index,
-				 0, 0, 0, &lb, 0, &is_identity_nat, 0))
+  if (snat_static_mapping_match (vm, sm, l_addr, l_port, rx_fib_index, proto,
+				 &sm_addr, &sm_port, &sm_fib_index, 0, 0, 0,
+				 &lb, 0, &is_identity_nat, 0))
     {
       is_sm = 0;
     }
@@ -398,7 +371,7 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
       is_sm = 1;
     }
 
-  if (PREDICT_TRUE (nat_proto == NAT_PROTOCOL_TCP))
+  if (PREDICT_TRUE (proto == IP_PROTOCOL_TCP))
     {
       if (PREDICT_FALSE (!tcp_flags_is_init (
 	    vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags)))
@@ -415,7 +388,7 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
     {
       s->in2out.addr = l_addr;
       s->in2out.port = l_port;
-      s->nat_proto = nat_proto;
+      s->proto = proto;
       s->in2out.fib_index = rx_fib_index;
       s->out2in.fib_index = outside_fib_index;
 
@@ -423,8 +396,8 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
       outside_port = l_port;
 
       // hairpinning?
-      int is_hairpinning = nat44_ed_external_sm_lookup (
-	sm, r_addr, r_port, nat_proto, outside_fib_index, &daddr, &dport);
+      int is_hairpinning = nat44_ed_external_sm_lookup (sm, r_addr, r_port,
+							proto, &daddr, &dport);
       s->flags |= is_hairpinning * SNAT_SESSION_FLAG_HAIRPINNING;
 
       // destination addr/port updated with real values in
@@ -432,7 +405,7 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
       nat_6t_o2i_flow_init (sm, thread_index, s, daddr, dport, daddr, 0,
 			    s->out2in.fib_index, proto);
       nat_6t_flow_daddr_rewrite_set (&s->o2i, l_addr.as_u32);
-      if (NAT_PROTOCOL_ICMP == nat_proto)
+      if (IP_PROTOCOL_ICMP == proto)
 	{
 	  nat_6t_flow_icmp_id_rewrite_set (&s->o2i, l_port);
 	}
@@ -442,10 +415,9 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 	}
       nat_6t_flow_txfib_rewrite_set (&s->o2i, rx_fib_index);
 
-      if (nat_ed_alloc_addr_and_port (
-	    sm, rx_fib_index, nat_proto, thread_index, l_addr,
-	    sm->port_per_thread, tsm->snat_thread_index, s, &outside_addr,
-	    &outside_port))
+      if (nat_ed_alloc_addr_and_port (sm, rx_fib_index, proto, thread_index,
+				      l_addr, tsm->snat_thread_index, s,
+				      &outside_addr, &outside_port))
 	{
 	  nat_elog_notice (sm, "addresses exhausted");
 	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
@@ -462,17 +434,17 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
       s->out2in.port = outside_port = sm_port;
       s->in2out.addr = l_addr;
       s->in2out.port = l_port;
-      s->nat_proto = nat_proto;
+      s->proto = proto;
       s->in2out.fib_index = rx_fib_index;
       s->out2in.fib_index = outside_fib_index;
       s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 
       // hairpinning?
-      int is_hairpinning = nat44_ed_external_sm_lookup (
-	sm, r_addr, r_port, nat_proto, outside_fib_index, &daddr, &dport);
+      int is_hairpinning = nat44_ed_external_sm_lookup (sm, r_addr, r_port,
+							proto, &daddr, &dport);
       s->flags |= is_hairpinning * SNAT_SESSION_FLAG_HAIRPINNING;
 
-      if (NAT_PROTOCOL_ICMP == nat_proto)
+      if (IP_PROTOCOL_ICMP == proto)
 	{
 	  nat_6t_o2i_flow_init (sm, thread_index, s, daddr, sm_port, sm_addr,
 				sm_port, s->out2in.fib_index, proto);
@@ -503,7 +475,7 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
   nat_6t_flow_saddr_rewrite_set (&s->i2o, outside_addr.as_u32);
   nat_6t_flow_daddr_rewrite_set (&s->i2o, daddr.as_u32);
 
-  if (NAT_PROTOCOL_ICMP == nat_proto)
+  if (IP_PROTOCOL_ICMP == proto)
     {
       nat_6t_flow_icmp_id_rewrite_set (&s->i2o, outside_port);
     }
@@ -521,17 +493,14 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
     }
 
   /* log NAT event */
-  nat_ipfix_logging_nat44_ses_create (thread_index,
-				      s->in2out.addr.as_u32,
-				      s->out2in.addr.as_u32,
-				      s->nat_proto,
-				      s->in2out.port,
-				      s->out2in.port, s->in2out.fib_index);
+  nat_ipfix_logging_nat44_ses_create (
+    thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32, s->proto,
+    s->in2out.port, s->out2in.port, s->in2out.fib_index);
 
   nat_syslog_nat44_sadd (0, s->in2out.fib_index, &s->in2out.addr,
 			 s->in2out.port, &s->ext_host_nat_addr,
 			 s->ext_host_nat_port, &s->out2in.addr, s->out2in.port,
-			 &s->ext_host_addr, s->ext_host_port, s->nat_proto, 0);
+			 &s->ext_host_addr, s->ext_host_port, s->proto, 0);
 
   per_vrf_sessions_register_session (s, thread_index);
 
@@ -540,12 +509,6 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 error:
   if (s)
     {
-      if (!is_sm)
-	{
-	  snat_free_outside_address_and_port (sm->addresses, thread_index,
-					      &outside_addr, outside_port,
-					      nat_proto);
-	}
       nat_ed_session_delete (sm, s, thread_index, 1);
     }
   *sessionp = s = NULL;
@@ -560,9 +523,10 @@ nat44_ed_not_translate (vlib_main_t *vm, snat_main_t *sm,
 {
   clib_bihash_kv_16_8_t kv, value;
 
-  init_ed_k (&kv, ip->dst_address, vnet_buffer (b)->ip.reass.l4_dst_port,
-	     ip->src_address, vnet_buffer (b)->ip.reass.l4_src_port,
-	     sm->outside_fib_index, ip->protocol);
+  init_ed_k (&kv, ip->dst_address.as_u32,
+	     vnet_buffer (b)->ip.reass.l4_dst_port, ip->src_address.as_u32,
+	     vnet_buffer (b)->ip.reass.l4_src_port, sm->outside_fib_index,
+	     ip->protocol);
 
   /* NAT packet aimed at external address if has active sessions */
   if (clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
@@ -607,18 +571,18 @@ nat_not_translate_output_feature_fwd (snat_main_t * sm, ip4_header_t * ip,
 					      &lookup_sport, &lookup_daddr,
 					      &lookup_dport, &lookup_protocol))
 	return 0;
-      init_ed_k (&kv, lookup_saddr, lookup_sport, lookup_daddr, lookup_dport,
-		 0, lookup_protocol);
+      init_ed_k (&kv, lookup_saddr.as_u32, lookup_sport, lookup_daddr.as_u32,
+		 lookup_dport, 0, lookup_protocol);
     }
   else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
     {
-      init_ed_k (&kv, ip->src_address, vnet_buffer (b)->ip.reass.l4_src_port,
-		 ip->dst_address, vnet_buffer (b)->ip.reass.l4_dst_port, 0,
-		 ip->protocol);
+      init_ed_k (&kv, ip->src_address.as_u32,
+		 vnet_buffer (b)->ip.reass.l4_src_port, ip->dst_address.as_u32,
+		 vnet_buffer (b)->ip.reass.l4_dst_port, 0, ip->protocol);
     }
   else
     {
-      init_ed_k (&kv, ip->src_address, 0, ip->dst_address, 0, 0,
+      init_ed_k (&kv, ip->src_address.as_u32, 0, ip->dst_address.as_u32, 0, 0,
 		 ip->protocol);
     }
 
@@ -665,8 +629,8 @@ nat44_ed_not_translate_output_feature (snat_main_t *sm, vlib_buffer_t *b,
   u32 tx_fib_index = ip4_fib_table_get_index_for_sw_if_index (tx_sw_if_index);
 
   /* src NAT check */
-  init_ed_k (&kv, ip->src_address, src_port, ip->dst_address, dst_port,
-	     tx_fib_index, ip->protocol);
+  init_ed_k (&kv, ip->src_address.as_u32, src_port, ip->dst_address.as_u32,
+	     dst_port, tx_fib_index, ip->protocol);
   if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     {
       ASSERT (thread_index == ed_value_get_thread_index (&value));
@@ -676,7 +640,7 @@ nat44_ed_not_translate_output_feature (snat_main_t *sm, vlib_buffer_t *b,
       if (nat44_is_ses_closed (s)
 	  && (!s->tcp_closed_timestamp || now >= s->tcp_closed_timestamp))
 	{
-	  nat_free_session_data (sm, s, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s, thread_index, 0);
 	  nat_ed_session_delete (sm, s, thread_index, 1);
 	}
       return 1;
@@ -703,8 +667,8 @@ nat44_ed_not_translate_output_feature (snat_main_t *sm, vlib_buffer_t *b,
       s = NULL;
     }
 
-  init_ed_k (&kv, ip->dst_address, dst_port, ip->src_address, src_port,
-	     rx_fib_index, ip->protocol);
+  init_ed_k (&kv, ip->dst_address.as_u32, dst_port, ip->src_address.as_u32,
+	     src_port, rx_fib_index, ip->protocol);
   if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     {
       ASSERT (thread_index == ed_value_get_thread_index (&value));
@@ -764,9 +728,8 @@ icmp_in2out_ed_slow_path (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
     }
   else
     {
-      if (PREDICT_FALSE (nat44_ed_not_translate (vm, sm, node, sw_if_index, b,
-						 ip, NAT_PROTOCOL_ICMP,
-						 rx_fib_index)))
+      if (PREDICT_FALSE (nat44_ed_not_translate (
+	    vm, sm, node, sw_if_index, b, ip, IP_PROTOCOL_ICMP, rx_fib_index)))
 	{
 	  return next;
 	}
@@ -819,7 +782,6 @@ nat44_ed_in2out_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
 					vlib_main_t *vm,
 					vlib_node_runtime_t *node)
 {
-  clib_bihash_kv_8_8_t kv, value;
   clib_bihash_kv_16_8_t s_kv, s_value;
   snat_static_mapping_t *m = NULL;
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
@@ -852,12 +814,11 @@ nat44_ed_in2out_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
       break;
     }
 
-  init_nat_k (&kv, ip->src_address, 0, rx_fib_index, 0);
-
   /* Try to find static mapping first */
-  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
+  m = nat44_ed_sm_i2o_lookup (sm, ip->src_address, 0, rx_fib_index,
+			      ip->protocol);
+  if (m)
     {
-      m = pool_elt_at_index (sm->static_mappings, value.value);
       new_src_addr = m->external_addr;
     }
   else
@@ -866,8 +827,9 @@ nat44_ed_in2out_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
 	{
 	  if (s->ext_host_addr.as_u32 == ip->dst_address.as_u32)
 	    {
-	      init_ed_k (&s_kv, s->out2in.addr, 0, ip->dst_address, 0,
-			 outside_fib_index, ip->protocol);
+	      init_ed_k (&s_kv, s->out2in.addr.as_u32, 0,
+			 ip->dst_address.as_u32, 0, outside_fib_index,
+			 ip->protocol);
 	      if (clib_bihash_search_16_8 (&sm->flow_hash, &s_kv, &s_value))
 		{
 		  new_src_addr = s->out2in.addr;
@@ -880,8 +842,9 @@ nat44_ed_in2out_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
 	{
 	  for (i = 0; i < vec_len (sm->addresses); i++)
 	    {
-	      init_ed_k (&s_kv, sm->addresses[i].addr, 0, ip->dst_address, 0,
-			 outside_fib_index, ip->protocol);
+	      init_ed_k (&s_kv, sm->addresses[i].addr.as_u32, 0,
+			 ip->dst_address.as_u32, 0, outside_fib_index,
+			 ip->protocol);
 	      if (clib_bihash_search_16_8 (&sm->flow_hash, &s_kv, &s_value))
 		{
 		  new_src_addr = sm->addresses[i].addr;
@@ -910,9 +873,8 @@ nat44_ed_in2out_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
   nat_6t_flow_txfib_rewrite_set (&s->i2o, outside_fib_index);
 
   // hairpinning?
-  int is_hairpinning =
-    nat44_ed_external_sm_lookup (sm, ip->dst_address, 0, NAT_PROTOCOL_OTHER,
-				 outside_fib_index, &new_dst_addr, NULL);
+  int is_hairpinning = nat44_ed_external_sm_lookup (
+    sm, ip->dst_address, 0, ip->protocol, &new_dst_addr, NULL);
   s->flags |= is_hairpinning * SNAT_SESSION_FLAG_HAIRPINNING;
 
   nat_6t_flow_daddr_rewrite_set (&s->i2o, new_dst_addr.as_u32);
@@ -925,7 +887,6 @@ nat44_ed_in2out_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
   nat_6t_flow_txfib_rewrite_set (&s->o2i, rx_fib_index);
 
   s->ext_host_addr.as_u32 = ip->dst_address.as_u32;
-  s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
   s->out2in.addr.as_u32 = new_src_addr.as_u32;
   s->out2in.fib_index = outside_fib_index;
   s->in2out.addr.as_u32 = ip->src_address.as_u32;
@@ -987,7 +948,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
       u32 rx_sw_if_index0, rx_fib_index0, iph_offset0 = 0;
       u32 tx_sw_if_index0;
       u32 cntr_sw_if_index0;
-      nat_protocol_t proto0;
+      ip_protocol_t proto0;
       ip4_header_t *ip0;
       snat_session_t *s0 = 0;
       clib_bihash_kv_16_8_t kv0, value0;
@@ -1039,7 +1000,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	  goto trace0;
 	}
 
-      proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      proto0 = ip0->protocol;
 
       if (is_output_feature)
 	{
@@ -1049,7 +1010,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	    goto trace0;
 	}
 
-      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
 	{
 	  if (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 		ICMP4_echo_request &&
@@ -1103,8 +1064,8 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	  s0 = NULL;
 	}
 
-      init_ed_k (&kv0, lookup.saddr, lookup.sport, lookup.daddr, lookup.dport,
-		 lookup.fib_index, lookup.proto);
+      init_ed_k (&kv0, lookup.saddr.as_u32, lookup.sport, lookup.daddr.as_u32,
+		 lookup.dport, lookup.fib_index, lookup.proto);
 
       // lookup flow
       if (clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
@@ -1126,7 +1087,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
       if (PREDICT_FALSE (per_vrf_sessions_is_expired (s0, thread_index)))
 	{
 	  // session is closed, go slow path
-	  nat_free_session_data (sm, s0, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	  nat_ed_session_delete (sm, s0, thread_index, 1);
 	  next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
 	  goto trace0;
@@ -1154,7 +1115,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	s0->last_heard + (f64) nat44_session_get_timeout (sm, s0);
       if (now >= sess_timeout_time)
 	{
-	  nat_free_session_data (sm, s0, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	  nat_ed_session_delete (sm, s0, thread_index, 1);
 	  // session is closed, go slow path
 	  next[0] = def_slow;
@@ -1175,7 +1136,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
       else
 	{
 	  translation_error = NAT_ED_TRNSL_ERR_FLOW_MISMATCH;
-	  nat_free_session_data (sm, s0, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	  nat_ed_session_delete (sm, s0, thread_index, 1);
 	  next[0] = NAT_NEXT_DROP;
 	  b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TRNSL_FAILED];
@@ -1186,7 +1147,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	  (translation_error = nat_6t_flow_buf_translate_i2o (
 	     vm, sm, b0, ip0, f, proto0, is_output_feature)))
 	{
-	  nat_free_session_data (sm, s0, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	  nat_ed_session_delete (sm, s0, thread_index, 1);
 	  next[0] = NAT_NEXT_DROP;
 	  b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TRNSL_FAILED];
@@ -1195,20 +1156,20 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 
       switch (proto0)
 	{
-	case NAT_PROTOCOL_TCP:
+	case IP_PROTOCOL_TCP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.in2out.tcp,
 					 thread_index, cntr_sw_if_index0, 1);
 	  nat44_set_tcp_session_state_i2o (sm, now, s0, b0, thread_index);
 	  break;
-	case NAT_PROTOCOL_UDP:
+	case IP_PROTOCOL_UDP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.in2out.udp,
 					 thread_index, cntr_sw_if_index0, 1);
 	  break;
-	case NAT_PROTOCOL_ICMP:
+	case IP_PROTOCOL_ICMP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.in2out.icmp,
 					 thread_index, cntr_sw_if_index0, 1);
 	  break;
-	case NAT_PROTOCOL_OTHER:
+	default:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.in2out.other,
 					 thread_index, cntr_sw_if_index0, 1);
 	  break;
@@ -1289,7 +1250,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
       u32 rx_sw_if_index0, rx_fib_index0, iph_offset0 = 0;
       u32 tx_sw_if_index0;
       u32 cntr_sw_if_index0;
-      nat_protocol_t proto0;
+      ip_protocol_t proto0;
       ip4_header_t *ip0;
       udp_header_t *udp0;
       icmp46_header_t *icmp0;
@@ -1326,9 +1287,9 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 
       udp0 = ip4_next_header (ip0);
       icmp0 = (icmp46_header_t *) udp0;
-      proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      proto0 = ip0->protocol;
 
-      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+      if (PREDICT_FALSE (nat44_ed_is_unk_proto (proto0)))
 	{
 	  s0 = nat44_ed_in2out_slowpath_unknown_proto (
 	    sm, b0, ip0, rx_fib_index0, thread_index, now, vm, node);
@@ -1340,7 +1301,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 		(translation_error = nat_6t_flow_buf_translate_i2o (
 		   vm, sm, b0, ip0, &s0->i2o, proto0, is_output_feature)))
 	    {
-	      nat_free_session_data (sm, s0, thread_index, 0);
+	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	      nat_ed_session_delete (sm, s0, thread_index, 1);
 	      next[0] = NAT_NEXT_DROP;
 	      b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TRNSL_FAILED];
@@ -1352,7 +1313,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 	  goto trace0;
 	}
 
-      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
 	{
 	  next[0] = icmp_in2out_ed_slow_path (
 	    sm, b0, ip0, icmp0, rx_sw_if_index0, rx_fib_index0, node, next[0],
@@ -1362,7 +1323,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 		(translation_error = nat_6t_flow_buf_translate_i2o (
 		   vm, sm, b0, ip0, &s0->i2o, proto0, is_output_feature)))
 	    {
-	      nat_free_session_data (sm, s0, thread_index, 0);
+	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	      nat_ed_session_delete (sm, s0, thread_index, 1);
 	      next[0] = NAT_NEXT_DROP;
 	      b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TRNSL_FAILED];
@@ -1374,10 +1335,10 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 	  goto trace0;
 	}
 
-      init_ed_k (&kv0, ip0->src_address,
-		 vnet_buffer (b0)->ip.reass.l4_src_port, ip0->dst_address,
-		 vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
-		 ip0->protocol);
+      init_ed_k (
+	&kv0, ip0->src_address.as_u32, vnet_buffer (b0)->ip.reass.l4_src_port,
+	ip0->dst_address.as_u32, vnet_buffer (b0)->ip.reass.l4_dst_port,
+	rx_fib_index0, ip0->protocol);
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
 	{
 	  ASSERT (thread_index == ed_value_get_thread_index (&value0));
@@ -1387,7 +1348,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 
 	  if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
 	    {
-	      nat_free_session_data (sm, s0, thread_index, 0);
+	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	      nat_ed_session_delete (sm, s0, thread_index, 1);
 	      s0 = NULL;
 	    }
@@ -1407,11 +1368,11 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 	       * Send DHCP packets to the ipv4 stack, or we won't
 	       * be able to use dhcp client on the outside interface
 	       */
-	      if (PREDICT_FALSE
-		  (proto0 == NAT_PROTOCOL_UDP
-		   && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
-		       clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_server))
-		   && ip0->dst_address.as_u32 == 0xffffffff))
+	      if (PREDICT_FALSE (
+		    proto0 == IP_PROTOCOL_UDP &&
+		    (vnet_buffer (b0)->ip.reass.l4_dst_port ==
+		     clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_server)) &&
+		    ip0->dst_address.as_u32 == 0xffffffff))
 		goto trace0;
 	    }
 	  else
@@ -1442,14 +1403,14 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 	  (translation_error = nat_6t_flow_buf_translate_i2o (
 	     vm, sm, b0, ip0, &s0->i2o, proto0, is_output_feature)))
 	{
-	  nat_free_session_data (sm, s0, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	  nat_ed_session_delete (sm, s0, thread_index, 1);
 	  next[0] = NAT_NEXT_DROP;
 	  b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TRNSL_FAILED];
 	  goto trace0;
 	}
 
-      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+      if (PREDICT_TRUE (proto0 == IP_PROTOCOL_TCP))
 	{
 	  vlib_increment_simple_counter (&sm->counters.slowpath.in2out.tcp,
 					 thread_index, cntr_sw_if_index0, 1);
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_inlines.h b/src/plugins/nat/nat44-ed/nat44_ed_inlines.h
index 0d75e736849..cb418960249 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_inlines.h
+++ b/src/plugins/nat/nat44-ed/nat44_ed_inlines.h
@@ -26,114 +26,50 @@
 #include <nat/lib/log.h>
 #include <nat/nat44-ed/nat44_ed.h>
 
-always_inline u64
-calc_nat_key (ip4_address_t addr, u16 port, u32 fib_index, u8 proto)
-{
-  ASSERT (fib_index <= (1 << 14) - 1);
-  ASSERT (proto <= (1 << 3) - 1);
-  return (u64) addr.as_u32 << 32 | (u64) port << 16 | fib_index << 3 |
-	 (proto & 0x7);
-}
-
-always_inline void
-split_nat_key (u64 key, ip4_address_t *addr, u16 *port, u32 *fib_index,
-	       nat_protocol_t *proto)
-{
-  if (addr)
-    {
-      addr->as_u32 = key >> 32;
-    }
-  if (port)
-    {
-      *port = (key >> 16) & (u16) ~0;
-    }
-  if (fib_index)
-    {
-      *fib_index = key >> 3 & ((1 << 13) - 1);
-    }
-  if (proto)
-    {
-      *proto = key & 0x7;
-    }
-}
-
-always_inline void
-init_nat_k (clib_bihash_kv_8_8_t *kv, ip4_address_t addr, u16 port,
-	    u32 fib_index, nat_protocol_t proto)
-{
-  kv->key = calc_nat_key (addr, port, fib_index, proto);
-  kv->value = ~0ULL;
-}
-
 always_inline void
-init_nat_kv (clib_bihash_kv_8_8_t *kv, ip4_address_t addr, u16 port,
-	     u32 fib_index, nat_protocol_t proto, u32 thread_index,
-	     u32 session_index)
+init_ed_k (clib_bihash_kv_16_8_t *kv, u32 l_addr, u16 l_port, u32 r_addr,
+	   u16 r_port, u32 fib_index, ip_protocol_t proto)
 {
-  init_nat_k (kv, addr, port, fib_index, proto);
-  kv->value = (u64) thread_index << 32 | session_index;
-}
-
-always_inline void
-init_nat_i2o_k (clib_bihash_kv_8_8_t *kv, snat_session_t *s)
-{
-  return init_nat_k (kv, s->in2out.addr, s->in2out.port, s->in2out.fib_index,
-		     s->nat_proto);
+  kv->key[0] = (u64) r_addr << 32 | l_addr;
+  kv->key[1] =
+    (u64) r_port << 48 | (u64) l_port << 32 | fib_index << 8 | proto;
 }
 
 always_inline void
-init_nat_i2o_kv (clib_bihash_kv_8_8_t *kv, snat_session_t *s, u32 thread_index,
-		 u32 session_index)
+init_ed_kv (clib_bihash_kv_16_8_t *kv, u32 l_addr, u16 l_port, u32 r_addr,
+	    u16 r_port, u32 fib_index, u8 proto, u32 thread_index,
+	    u32 session_index)
 {
-  init_nat_k (kv, s->in2out.addr, s->in2out.port, s->in2out.fib_index,
-	      s->nat_proto);
+  init_ed_k (kv, l_addr, l_port, r_addr, r_port, fib_index, proto);
   kv->value = (u64) thread_index << 32 | session_index;
 }
 
 always_inline void
-init_nat_o2i_k (clib_bihash_kv_8_8_t *kv, snat_session_t *s)
+nat44_ed_sm_init_i2o_kv (clib_bihash_kv_16_8_t *kv, u32 addr, u16 port,
+			 u32 fib_index, u8 proto, u32 sm_index)
 {
-  return init_nat_k (kv, s->out2in.addr, s->out2in.port, s->out2in.fib_index,
-		     s->nat_proto);
+  return init_ed_kv (kv, addr, port, 0, 0, fib_index, proto, 0, sm_index);
 }
 
 always_inline void
-init_nat_o2i_kv (clib_bihash_kv_8_8_t *kv, snat_session_t *s, u32 thread_index,
-		 u32 session_index)
-{
-  init_nat_k (kv, s->out2in.addr, s->out2in.port, s->out2in.fib_index,
-	      s->nat_proto);
-  kv->value = (u64) thread_index << 32 | session_index;
-}
-
-always_inline u32
-nat_value_get_thread_index (clib_bihash_kv_8_8_t *value)
-{
-  return value->value >> 32;
-}
-
-always_inline u32
-nat_value_get_session_index (clib_bihash_kv_8_8_t *value)
+nat44_ed_sm_init_o2i_kv (clib_bihash_kv_16_8_t *kv, u32 e_addr, u16 e_port,
+			 u32 fib_index, u8 proto, u32 sm_index)
 {
-  return value->value & ~(u32) 0;
+  return init_ed_kv (kv, 0, 0, e_addr, e_port, fib_index, proto, 0, sm_index);
 }
 
 always_inline void
-init_ed_k (clib_bihash_kv_16_8_t *kv, ip4_address_t l_addr, u16 l_port,
-	   ip4_address_t r_addr, u16 r_port, u32 fib_index, u8 proto)
+nat44_ed_sm_init_i2o_k (clib_bihash_kv_16_8_t *kv, u32 addr, u16 port,
+			u32 fib_index, u8 proto)
 {
-  kv->key[0] = (u64) r_addr.as_u32 << 32 | l_addr.as_u32;
-  kv->key[1] =
-    (u64) r_port << 48 | (u64) l_port << 32 | fib_index << 8 | proto;
+  return nat44_ed_sm_init_i2o_kv (kv, addr, port, fib_index, proto, 0);
 }
 
 always_inline void
-init_ed_kv (clib_bihash_kv_16_8_t *kv, ip4_address_t l_addr, u16 l_port,
-	    ip4_address_t r_addr, u16 r_port, u32 fib_index, u8 proto,
-	    u32 thread_index, u32 session_index)
+nat44_ed_sm_init_o2i_k (clib_bihash_kv_16_8_t *kv, u32 e_addr, u16 e_port,
+			u32 fib_index, u8 proto)
 {
-  init_ed_k (kv, l_addr, l_port, r_addr, r_port, fib_index, proto);
-  kv->value = (u64) thread_index << 32 | session_index;
+  return nat44_ed_sm_init_o2i_kv (kv, e_addr, e_port, fib_index, proto, 0);
 }
 
 always_inline u32
@@ -215,16 +151,16 @@ nat_get_icmp_session_lookup_values (vlib_buffer_t *b, ip4_header_t *ip0,
       *lookup_protocol = inner_ip0->protocol;
       lookup_saddr->as_u32 = inner_ip0->dst_address.as_u32;
       lookup_daddr->as_u32 = inner_ip0->src_address.as_u32;
-      switch (ip_proto_to_nat_proto (inner_ip0->protocol))
+      switch (inner_ip0->protocol)
 	{
-	case NAT_PROTOCOL_ICMP:
+	case IP_PROTOCOL_ICMP:
 	  inner_icmp0 = (icmp46_header_t *) l4_header;
 	  inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
 	  *lookup_sport = inner_echo0->identifier;
 	  *lookup_dport = inner_echo0->identifier;
 	  break;
-	case NAT_PROTOCOL_UDP:
-	case NAT_PROTOCOL_TCP:
+	case IP_PROTOCOL_UDP:
+	case IP_PROTOCOL_TCP:
 	  *lookup_sport = ((tcp_udp_header_t *) l4_header)->dst_port;
 	  *lookup_dport = ((tcp_udp_header_t *) l4_header)->src_port;
 	  break;
@@ -238,13 +174,15 @@ nat_get_icmp_session_lookup_values (vlib_buffer_t *b, ip4_header_t *ip0,
 always_inline u32
 nat44_session_get_timeout (snat_main_t *sm, snat_session_t *s)
 {
-  switch (s->nat_proto)
+  switch (s->proto)
     {
-    case NAT_PROTOCOL_ICMP:
+    case IP_PROTOCOL_ICMP:
+      /* fallthrough */
+    case IP_PROTOCOL_ICMP6:
       return sm->timeouts.icmp;
-    case NAT_PROTOCOL_UDP:
+    case IP_PROTOCOL_UDP:
       return sm->timeouts.udp;
-    case NAT_PROTOCOL_TCP:
+    case IP_PROTOCOL_TCP:
       {
 	if (s->state)
 	  return sm->timeouts.tcp.transitory;
@@ -300,7 +238,7 @@ nat_ed_lru_insert (snat_main_per_thread_data_t *tsm, snat_session_t *s,
 static_always_inline void
 nat_6t_flow_to_ed_k (clib_bihash_kv_16_8_t *kv, nat_6t_flow_t *f)
 {
-  init_ed_k (kv, f->match.saddr, f->match.sport, f->match.daddr,
+  init_ed_k (kv, f->match.saddr.as_u32, f->match.sport, f->match.daddr.as_u32,
 	     f->match.dport, f->match.fib_index, f->match.proto);
 }
 
@@ -308,7 +246,7 @@ static_always_inline void
 nat_6t_flow_to_ed_kv (clib_bihash_kv_16_8_t *kv, nat_6t_flow_t *f,
 		      u32 thread_idx, u32 session_idx)
 {
-  init_ed_kv (kv, f->match.saddr, f->match.sport, f->match.daddr,
+  init_ed_kv (kv, f->match.saddr.as_u32, f->match.sport, f->match.daddr.as_u32,
 	      f->match.dport, f->match.fib_index, f->match.proto, thread_idx,
 	      session_idx);
 }
@@ -348,6 +286,15 @@ nat_ed_ses_o2i_flow_hash_add_del (snat_main_t *sm, u32 thread_idx,
   else
     {
       nat_6t_flow_to_ed_kv (&kv, &s->o2i, thread_idx, s - tsm->sessions);
+      if (!(s->flags & SNAT_SESSION_FLAG_STATIC_MAPPING))
+	{
+	  if (nat44_ed_sm_o2i_lookup (sm, s->o2i.match.daddr,
+				      s->o2i.match.dport, 0,
+				      s->o2i.match.proto))
+	    {
+	      return -1;
+	    }
+	}
       nat_6t_l3_l4_csum_calc (&s->o2i);
     }
   ASSERT (thread_idx == s->thread_index);
@@ -396,7 +343,7 @@ nat_lru_free_one_with_head (snat_main_t *sm, int thread_index, f64 now,
       if (now >= sess_timeout_time ||
 	  (s->tcp_closed_timestamp && now >= s->tcp_closed_timestamp))
 	{
-	  nat_free_session_data (sm, s, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s, thread_index, 0);
 	  nat_ed_session_delete (sm, s, thread_index, 0);
 	  return 1;
 	}
@@ -868,6 +815,19 @@ nat44_session_update_lru (snat_main_t *sm, snat_session_t *s, u32 thread_index)
     }
 }
 
+static_always_inline int
+nat44_ed_is_unk_proto (u8 proto)
+{
+  static const int lookup_table[256] = {
+    [IP_PROTOCOL_TCP] = 1,
+    [IP_PROTOCOL_UDP] = 1,
+    [IP_PROTOCOL_ICMP] = 1,
+    [IP_PROTOCOL_ICMP6] = 1,
+  };
+
+  return 1 - lookup_table[proto];
+}
+
 #endif /* __included_nat44_ed_inlines_h__ */
 
 /*
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_out2in.c b/src/plugins/nat/nat44-ed/nat44_ed_out2in.c
index cb21b0f62c5..5ad57a17098 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_out2in.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_out2in.c
@@ -25,7 +25,6 @@
 #include <vnet/udp/udp_local.h>
 #include <vppinfra/error.h>
 
-#include <nat/lib/nat_syslog.h>
 #include <nat/lib/ipfix_logging.h>
 
 #include <nat/nat44-ed/nat44_ed.h>
@@ -127,8 +126,8 @@ next_src_nat (snat_main_t *sm, ip4_header_t *ip, u16 src_port, u16 dst_port,
 {
   clib_bihash_kv_16_8_t kv, value;
 
-  init_ed_k (&kv, ip->src_address, src_port, ip->dst_address, dst_port,
-	     rx_fib_index, ip->protocol);
+  init_ed_k (&kv, ip->src_address.as_u32, src_port, ip->dst_address.as_u32,
+	     dst_port, rx_fib_index, ip->protocol);
   if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     return 1;
 
@@ -142,8 +141,8 @@ static void create_bypass_for_fwd (snat_main_t *sm, vlib_buffer_t *b,
 static snat_session_t *create_session_for_static_mapping_ed (
   snat_main_t *sm, vlib_buffer_t *b, ip4_address_t i2o_addr, u16 i2o_port,
   u32 i2o_fib_index, ip4_address_t o2i_addr, u16 o2i_port, u32 o2i_fib_index,
-  nat_protocol_t nat_proto, vlib_node_runtime_t *node, u32 rx_fib_index,
-  u32 thread_index, twice_nat_type_t twice_nat, lb_nat_type_t lb_nat, f64 now,
+  ip_protocol_t proto, vlib_node_runtime_t *node, u32 thread_index,
+  twice_nat_type_t twice_nat, lb_nat_type_t lb_nat, f64 now,
   snat_static_mapping_t *mapping);
 
 static inline u32
@@ -180,10 +179,10 @@ icmp_out2in_ed_slow_path (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
       goto out;
     }
 
-  if (snat_static_mapping_match (
-	vm, sm, ip->dst_address, lookup_sport, rx_fib_index,
-	ip_proto_to_nat_proto (ip->protocol), &sm_addr, &sm_port,
-	&sm_fib_index, 1, &is_addr_only, 0, 0, 0, &identity_nat, &m))
+  if (snat_static_mapping_match (vm, sm, ip->dst_address, lookup_sport,
+				 rx_fib_index, ip->protocol, &sm_addr,
+				 &sm_port, &sm_fib_index, 1, &is_addr_only, 0,
+				 0, 0, &identity_nat, &m))
     {
       // static mapping not matched
       if (!sm->forwarding_enabled)
@@ -229,8 +228,8 @@ icmp_out2in_ed_slow_path (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
   /* Create session initiated by host from external network */
   s = create_session_for_static_mapping_ed (
     sm, b, sm_addr, sm_port, sm_fib_index, ip->dst_address, lookup_sport,
-    rx_fib_index, ip_proto_to_nat_proto (lookup_protocol), node, rx_fib_index,
-    thread_index, 0, 0, vlib_time_now (vm), m);
+    rx_fib_index, lookup_protocol, node, thread_index, 0, 0,
+    vlib_time_now (vm), m);
   if (!s)
     next = NAT_NEXT_DROP;
 
@@ -265,44 +264,29 @@ out:
   return next;
 }
 
-// allocate exact address based on preference
 static_always_inline int
-nat_alloc_addr_and_port_exact (snat_address_t * a,
-			       u32 thread_index,
-			       nat_protocol_t proto,
-			       ip4_address_t * addr,
-			       u16 * port,
-			       u16 port_per_thread, u32 snat_thread_index)
+nat44_ed_alloc_i2o_port (snat_main_t *sm, snat_address_t *a, snat_session_t *s,
+			 ip4_address_t i2o_addr, u16 i2o_port,
+			 u32 i2o_fib_index, ip_protocol_t proto,
+			 u32 thread_index, u32 snat_thread_index,
+			 ip4_address_t *outside_addr, u16 *outside_port)
 {
-  snat_main_t *sm = &snat_main;
   u32 portnum;
 
-  switch (proto)
+  for (int i = 0; i < ED_PORT_ALLOC_ATTEMPTS; ++i)
     {
-#define _(N, j, n, s) \
-    case NAT_PROTOCOL_##N: \
-      if (a->busy_##n##_ports_per_thread[thread_index] < port_per_thread) \
-        { \
-          while (1) \
-            { \
-              portnum = (port_per_thread * \
-                snat_thread_index) + \
-                snat_random_port(0, port_per_thread - 1) + 1024; \
-              if (a->busy_##n##_port_refcounts[portnum]) \
-                continue; \
-	      --a->busy_##n##_port_refcounts[portnum]; \
-              a->busy_##n##_ports_per_thread[thread_index]++; \
-              a->busy_##n##_ports++; \
-              *addr = a->addr; \
-              *port = clib_host_to_net_u16(portnum); \
-              return 0; \
-            } \
-        } \
-      break;
-      foreach_nat_protocol
-#undef _
-	default : nat_elog_info (sm, "unknown protocol");
-      return 1;
+      portnum = (sm->port_per_thread * snat_thread_index) +
+		snat_random_port (0, sm->port_per_thread - 1) + 1024;
+      portnum = clib_host_to_net_u16 (portnum);
+      nat_6t_i2o_flow_init (sm, thread_index, s, i2o_addr, i2o_port, a->addr,
+			    portnum, i2o_fib_index, proto);
+      if (!nat_ed_ses_i2o_flow_hash_add_del (sm, thread_index, s,
+					     1 /* is_add */))
+	{
+	  *outside_addr = a->addr;
+	  *outside_port = portnum;
+	  return 0;
+	}
     }
 
   /* Totally out of translations to use... */
@@ -311,80 +295,56 @@ nat_alloc_addr_and_port_exact (snat_address_t * a,
 }
 
 static_always_inline int
-nat44_ed_alloc_outside_addr_and_port (snat_address_t *addresses, u32 fib_index,
-				      u32 thread_index, nat_protocol_t proto,
-				      ip4_address_t *addr, u16 *port,
-				      u16 port_per_thread,
-				      u32 snat_thread_index)
+nat44_ed_alloc_i2o_addr_and_port (snat_main_t *sm, snat_address_t *addresses,
+				  snat_session_t *s, ip4_address_t i2o_addr,
+				  u16 i2o_port, u32 i2o_fib_index,
+				  ip_protocol_t proto, u32 thread_index,
+				  u32 snat_thread_index,
+				  ip4_address_t *outside_addr,
+				  u16 *outside_port)
 {
-  snat_main_t *sm = &snat_main;
   snat_address_t *a, *ga = 0;
-  u32 portnum;
   int i;
 
-  for (i = 0; i < vec_len (addresses); i++)
+  if (vec_len (addresses) > 0)
     {
-      a = addresses + i;
-      switch (proto)
+      int s_addr_offset = i2o_addr.as_u32 % vec_len (addresses);
+
+      for (i = s_addr_offset; i < vec_len (addresses); ++i)
 	{
-#define _(N, j, n, s)                                                         \
-  case NAT_PROTOCOL_##N:                                                      \
-    if (a->busy_##n##_ports_per_thread[thread_index] < port_per_thread)       \
-      {                                                                       \
-	if (a->fib_index == fib_index)                                        \
-	  {                                                                   \
-	    while (1)                                                         \
-	      {                                                               \
-		portnum = (port_per_thread * snat_thread_index) +             \
-			  snat_random_port (0, port_per_thread - 1) + 1024;   \
-		if (a->busy_##n##_port_refcounts[portnum])                    \
-		  continue;                                                   \
-		--a->busy_##n##_port_refcounts[portnum];                      \
-		a->busy_##n##_ports_per_thread[thread_index]++;               \
-		a->busy_##n##_ports++;                                        \
-		*addr = a->addr;                                              \
-		*port = clib_host_to_net_u16 (portnum);                       \
-		return 0;                                                     \
-	      }                                                               \
-	  }                                                                   \
-	else if (a->fib_index == ~0)                                          \
-	  {                                                                   \
-	    ga = a;                                                           \
-	  }                                                                   \
-      }                                                                       \
-    break;
-	  foreach_nat_protocol
-#undef _
-	    default : nat_elog_info (sm, "unknown protocol");
-	  return 1;
+	  a = addresses + i;
+	  if (a->fib_index == i2o_fib_index)
+	    {
+	      return nat44_ed_alloc_i2o_port (
+		sm, a, s, i2o_addr, i2o_port, i2o_fib_index, proto,
+		thread_index, snat_thread_index, outside_addr, outside_port);
+	    }
+	  else if (a->fib_index == ~0)
+	    {
+	      ga = a;
+	    }
 	}
-    }
 
-  if (ga)
-    {
-      a = ga;
-      switch (proto)
+      for (i = 0; i < s_addr_offset; ++i)
 	{
-#define _(N, j, n, s)                                                         \
-  case NAT_PROTOCOL_##N:                                                      \
-    while (1)                                                                 \
-      {                                                                       \
-	portnum = (port_per_thread * snat_thread_index) +                     \
-		  snat_random_port (0, port_per_thread - 1) + 1024;           \
-	if (a->busy_##n##_port_refcounts[portnum])                            \
-	  continue;                                                           \
-	++a->busy_##n##_port_refcounts[portnum];                              \
-	a->busy_##n##_ports_per_thread[thread_index]++;                       \
-	a->busy_##n##_ports++;                                                \
-	*addr = a->addr;                                                      \
-	*port = clib_host_to_net_u16 (portnum);                               \
-	return 0;                                                             \
-      }
-	  break;
-	  foreach_nat_protocol
-#undef _
-	    default : nat_elog_info (sm, "unknown protocol");
-	  return 1;
+	  a = addresses + i;
+	  if (a->fib_index == i2o_fib_index)
+	    {
+	      return nat44_ed_alloc_i2o_port (
+		sm, a, s, i2o_addr, i2o_port, i2o_fib_index, proto,
+		thread_index, snat_thread_index, outside_addr, outside_port);
+	    }
+	  else if (a->fib_index == ~0)
+	    {
+	      ga = a;
+	    }
+	}
+
+      if (ga)
+	{
+	  return nat44_ed_alloc_i2o_port (
+	    sm, a, s, i2o_addr, i2o_port, i2o_fib_index, proto, thread_index,
+	    snat_thread_index, outside_addr, outside_port);
 	}
     }
 
@@ -397,23 +357,23 @@ static snat_session_t *
 create_session_for_static_mapping_ed (
   snat_main_t *sm, vlib_buffer_t *b, ip4_address_t i2o_addr, u16 i2o_port,
   u32 i2o_fib_index, ip4_address_t o2i_addr, u16 o2i_port, u32 o2i_fib_index,
-  nat_protocol_t nat_proto, vlib_node_runtime_t *node, u32 rx_fib_index,
-  u32 thread_index, twice_nat_type_t twice_nat, lb_nat_type_t lb_nat, f64 now,
+  ip_protocol_t proto, vlib_node_runtime_t *node, u32 thread_index,
+  twice_nat_type_t twice_nat, lb_nat_type_t lb_nat, f64 now,
   snat_static_mapping_t *mapping)
 {
   snat_session_t *s;
   ip4_header_t *ip;
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 
-  if (PREDICT_FALSE
-      (nat44_ed_maximum_sessions_exceeded (sm, rx_fib_index, thread_index)))
+  if (PREDICT_FALSE (
+	nat44_ed_maximum_sessions_exceeded (sm, o2i_fib_index, thread_index)))
     {
       b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
       nat_elog_notice (sm, "maximum sessions exceeded");
       return 0;
     }
 
-  s = nat_ed_session_alloc (sm, thread_index, now, nat_proto);
+  s = nat_ed_session_alloc (sm, thread_index, now, proto);
   if (!s)
     {
       b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
@@ -425,7 +385,7 @@ create_session_for_static_mapping_ed (
 
   s->ext_host_addr.as_u32 = ip->src_address.as_u32;
   s->ext_host_port =
-    nat_proto == NAT_PROTOCOL_ICMP ? 0 : vnet_buffer (b)->ip.reass.l4_src_port;
+    proto == IP_PROTOCOL_ICMP ? 0 : vnet_buffer (b)->ip.reass.l4_src_port;
   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
   if (lb_nat)
     s->flags |= SNAT_SESSION_FLAG_LOAD_BALANCING;
@@ -437,9 +397,9 @@ create_session_for_static_mapping_ed (
   s->in2out.addr = i2o_addr;
   s->in2out.port = i2o_port;
   s->in2out.fib_index = i2o_fib_index;
-  s->nat_proto = nat_proto;
+  s->proto = proto;
 
-  if (NAT_PROTOCOL_ICMP == nat_proto)
+  if (IP_PROTOCOL_ICMP == proto)
     {
       nat_6t_o2i_flow_init (sm, thread_index, s, s->ext_host_addr, o2i_port,
 			    o2i_addr, o2i_port, o2i_fib_index, ip->protocol);
@@ -485,33 +445,23 @@ create_session_for_static_mapping_ed (
 
       if (filter)
 	{
-	  rc = nat_alloc_addr_and_port_exact (filter,
-					      thread_index,
-					      nat_proto,
-					      &s->ext_host_nat_addr,
-					      &s->ext_host_nat_port,
-					      sm->port_per_thread,
-					      tsm->snat_thread_index);
+	  rc = nat44_ed_alloc_i2o_port (
+	    sm, filter, s, i2o_addr, i2o_port, i2o_fib_index, proto,
+	    thread_index, tsm->snat_thread_index, &s->ext_host_nat_addr,
+	    &s->ext_host_nat_port);
 	  s->flags |= SNAT_SESSION_FLAG_EXACT_ADDRESS;
 	}
       else
 	{
-	  rc = nat44_ed_alloc_outside_addr_and_port (
-	    sm->twice_nat_addresses, 0, thread_index, nat_proto,
-	    &s->ext_host_nat_addr, &s->ext_host_nat_port, sm->port_per_thread,
-	    tsm->snat_thread_index);
+	  rc = nat44_ed_alloc_i2o_addr_and_port (
+	    sm, sm->twice_nat_addresses, s, i2o_addr, i2o_port, i2o_fib_index,
+	    proto, thread_index, tsm->snat_thread_index, &s->ext_host_nat_addr,
+	    &s->ext_host_nat_port);
 	}
 
       if (rc)
 	{
 	  b->error = node->errors[NAT_OUT2IN_ED_ERROR_OUT_OF_PORTS];
-	  if (nat_ed_ses_o2i_flow_hash_add_del (sm, thread_index, s, 0))
-	    {
-	      nat_elog_warn (sm, "out2in flow hash del failed");
-	    }
-	  snat_free_outside_address_and_port (
-	    sm->twice_nat_addresses, thread_index, &s->ext_host_nat_addr,
-	    s->ext_host_nat_port, s->nat_proto);
 	  nat_ed_session_delete (sm, s, thread_index, 1);
 	  return 0;
 	}
@@ -519,7 +469,7 @@ create_session_for_static_mapping_ed (
       s->flags |= SNAT_SESSION_FLAG_TWICE_NAT;
 
       nat_6t_flow_saddr_rewrite_set (&s->o2i, s->ext_host_nat_addr.as_u32);
-      if (NAT_PROTOCOL_ICMP == nat_proto)
+      if (IP_PROTOCOL_ICMP == proto)
 	{
 	  nat_6t_flow_icmp_id_rewrite_set (&s->o2i, s->ext_host_nat_port);
 	}
@@ -530,11 +480,8 @@ create_session_for_static_mapping_ed (
 
       nat_6t_l3_l4_csum_calc (&s->o2i);
 
-      nat_6t_i2o_flow_init (sm, thread_index, s, i2o_addr, i2o_port,
-			    s->ext_host_nat_addr, s->ext_host_nat_port,
-			    i2o_fib_index, ip->protocol);
       nat_6t_flow_daddr_rewrite_set (&s->i2o, s->ext_host_addr.as_u32);
-      if (NAT_PROTOCOL_ICMP == nat_proto)
+      if (IP_PROTOCOL_ICMP == proto)
 	{
 	  nat_6t_flow_icmp_id_rewrite_set (&s->i2o, s->ext_host_port);
 	}
@@ -542,10 +489,21 @@ create_session_for_static_mapping_ed (
 	{
 	  nat_6t_flow_dport_rewrite_set (&s->i2o, s->ext_host_port);
 	}
+
+      nat_6t_flow_saddr_rewrite_set (&s->i2o, o2i_addr.as_u32);
+      if (IP_PROTOCOL_ICMP == proto)
+	{
+	  nat_6t_flow_icmp_id_rewrite_set (&s->i2o, o2i_port);
+	}
+      else
+	{
+	  nat_6t_flow_sport_rewrite_set (&s->i2o, o2i_port);
+	}
+      nat_6t_l3_l4_csum_calc (&s->i2o);
     }
   else
     {
-      if (NAT_PROTOCOL_ICMP == nat_proto)
+      if (IP_PROTOCOL_ICMP == proto)
 	{
 	  nat_6t_i2o_flow_init (sm, thread_index, s, i2o_addr, i2o_port,
 				s->ext_host_addr, i2o_port, i2o_fib_index,
@@ -557,10 +515,9 @@ create_session_for_static_mapping_ed (
 				s->ext_host_addr, s->ext_host_port,
 				i2o_fib_index, ip->protocol);
 	}
-    }
 
   nat_6t_flow_saddr_rewrite_set (&s->i2o, o2i_addr.as_u32);
-  if (NAT_PROTOCOL_ICMP == nat_proto)
+  if (IP_PROTOCOL_ICMP == proto)
     {
       nat_6t_flow_icmp_id_rewrite_set (&s->i2o, o2i_port);
     }
@@ -579,18 +536,15 @@ create_session_for_static_mapping_ed (
       nat_ed_session_delete (sm, s, thread_index, 1);
       return 0;
     }
-
-  nat_ipfix_logging_nat44_ses_create (thread_index,
-				      s->in2out.addr.as_u32,
-				      s->out2in.addr.as_u32,
-				      s->nat_proto,
-				      s->in2out.port,
-				      s->out2in.port, s->in2out.fib_index);
+    }
+  nat_ipfix_logging_nat44_ses_create (
+    thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32, s->proto,
+    s->in2out.port, s->out2in.port, s->in2out.fib_index);
 
   nat_syslog_nat44_sadd (0, s->in2out.fib_index, &s->in2out.addr,
 			 s->in2out.port, &s->ext_host_nat_addr,
 			 s->ext_host_nat_port, &s->out2in.addr, s->out2in.port,
-			 &s->ext_host_addr, s->ext_host_port, s->nat_proto,
+			 &s->ext_host_addr, s->ext_host_port, s->proto,
 			 nat44_ed_is_twice_nat_session (s));
 
   per_vrf_sessions_register_session (s, thread_index);
@@ -634,8 +588,8 @@ create_bypass_for_fwd (snat_main_t *sm, vlib_buffer_t *b, snat_session_t *s,
       lookup_protocol = ip->protocol;
     }
 
-  init_ed_k (&kv, lookup_saddr, lookup_sport, lookup_daddr, lookup_dport,
-	     rx_fib_index, lookup_protocol);
+  init_ed_k (&kv, lookup_saddr.as_u32, lookup_sport, lookup_daddr.as_u32,
+	     lookup_dport, rx_fib_index, lookup_protocol);
 
   if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     {
@@ -652,8 +606,6 @@ create_bypass_for_fwd (snat_main_t *sm, vlib_buffer_t *b, snat_session_t *s,
     }
   else
     {
-      u32 proto;
-
       if (PREDICT_FALSE
 	  (nat44_ed_maximum_sessions_exceeded
 	   (sm, rx_fib_index, thread_index)))
@@ -666,19 +618,12 @@ create_bypass_for_fwd (snat_main_t *sm, vlib_buffer_t *b, snat_session_t *s,
 	  return;
 	}
 
-      proto = ip_proto_to_nat_proto (ip->protocol);
-
       s->ext_host_addr = ip->src_address;
       s->ext_host_port = lookup_dport;
       s->flags |= SNAT_SESSION_FLAG_FWD_BYPASS;
       s->out2in.addr = ip->dst_address;
       s->out2in.port = lookup_sport;
-      s->nat_proto = proto;
-      if (proto == NAT_PROTOCOL_OTHER)
-	{
-	  s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
-	  s->out2in.port = ip->protocol;
-	}
+      s->proto = ip->protocol;
       s->out2in.fib_index = rx_fib_index;
       s->in2out.addr = s->out2in.addr;
       s->in2out.port = s->out2in.port;
@@ -719,7 +664,6 @@ nat44_ed_out2in_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
 					vlib_main_t *vm,
 					vlib_node_runtime_t *node)
 {
-  clib_bihash_kv_8_8_t kv, value;
   snat_static_mapping_t *m;
   snat_session_t *s;
 
@@ -731,15 +675,13 @@ nat44_ed_out2in_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
       return 0;
     }
 
-  init_nat_k (&kv, ip->dst_address, 0, 0, 0);
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+  m = nat44_ed_sm_o2i_lookup (sm, ip->dst_address, 0, 0, ip->protocol);
+  if (!m)
     {
       b->error = node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
       return 0;
     }
 
-  m = pool_elt_at_index (sm->static_mappings, value.value);
-
   /* Create a new session */
   s = nat_ed_session_alloc (sm, thread_index, now, ip->protocol);
   if (!s)
@@ -750,7 +692,6 @@ nat44_ed_out2in_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
     }
 
   s->ext_host_addr.as_u32 = ip->src_address.as_u32;
-  s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
   s->out2in.addr.as_u32 = ip->dst_address.as_u32;
   s->out2in.fib_index = rx_fib_index;
@@ -813,7 +754,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
     {
       vlib_buffer_t *b0;
       u32 sw_if_index0, rx_fib_index0;
-      nat_protocol_t proto0;
+      ip_protocol_t proto0;
       ip4_header_t *ip0;
       snat_session_t *s0 = 0;
       clib_bihash_kv_16_8_t kv0, value0;
@@ -862,9 +803,9 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      proto0 = ip0->protocol;
 
-      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
 	{
 	  if (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 		ICMP4_echo_request &&
@@ -913,8 +854,8 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 	  s0 = NULL;
 	}
 
-      init_ed_k (&kv0, lookup.saddr, lookup.sport, lookup.daddr, lookup.dport,
-		 lookup.fib_index, lookup.proto);
+      init_ed_k (&kv0, lookup.saddr.as_u32, lookup.sport, lookup.daddr.as_u32,
+		 lookup.dport, lookup.fib_index, lookup.proto);
 
       // lookup flow
       if (clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
@@ -935,7 +876,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
       if (PREDICT_FALSE (per_vrf_sessions_is_expired (s0, thread_index)))
 	{
 	  // session is closed, go slow path
-	  nat_free_session_data (sm, s0, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	  nat_ed_session_delete (sm, s0, thread_index, 1);
 	  slow_path_reason = NAT_ED_SP_REASON_VRF_EXPIRED;
 	  next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
@@ -966,7 +907,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
       if (now >= sess_timeout_time)
 	{
 	  // session is closed, go slow path
-	  nat_free_session_data (sm, s0, thread_index, 0);
+	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	  nat_ed_session_delete (sm, s0, thread_index, 1);
 	  slow_path_reason = NAT_ED_SP_SESS_EXPIRED;
 	  next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
@@ -989,7 +930,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 	   * be able to use dhcp client on the outside interface
 	   */
 	  if (PREDICT_FALSE (
-		proto0 == NAT_PROTOCOL_UDP &&
+		proto0 == IP_PROTOCOL_UDP &&
 		(vnet_buffer (b0)->ip.reass.l4_dst_port ==
 		 clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
 	    {
@@ -1014,7 +955,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 		  //  create_bypass_for_fwd (sm, b0, s0, ip0, rx_fib_index0,
 		  //                       thread_index);
 		  translation_error = NAT_ED_TRNSL_ERR_FLOW_MISMATCH;
-		  nat_free_session_data (sm, s0, thread_index, 0);
+		  nat44_ed_free_session_data (sm, s0, thread_index, 0);
 		  nat_ed_session_delete (sm, s0, thread_index, 1);
 		  next[0] = NAT_NEXT_DROP;
 		  b0->error = node->errors[NAT_OUT2IN_ED_ERROR_TRNSL_FAILED];
@@ -1034,7 +975,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 
       switch (proto0)
 	{
-	case NAT_PROTOCOL_TCP:
+	case IP_PROTOCOL_TCP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.tcp,
 					 thread_index, sw_if_index0, 1);
 	  nat44_set_tcp_session_state_o2i (sm, now, s0,
@@ -1046,15 +987,15 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 					   reass.tcp_seq_number,
 					   thread_index);
 	  break;
-	case NAT_PROTOCOL_UDP:
+	case IP_PROTOCOL_UDP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.udp,
 					 thread_index, sw_if_index0, 1);
 	  break;
-	case NAT_PROTOCOL_ICMP:
+	case IP_PROTOCOL_ICMP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.icmp,
 					 thread_index, sw_if_index0, 1);
 	  break;
-	case NAT_PROTOCOL_OTHER:
+	default:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.other,
 					 thread_index, sw_if_index0, 1);
 	  break;
@@ -1132,7 +1073,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
     {
       vlib_buffer_t *b0;
       u32 sw_if_index0, rx_fib_index0;
-      nat_protocol_t proto0;
+      ip_protocol_t proto0;
       ip4_header_t *ip0;
       udp_header_t *udp0;
       icmp46_header_t *icmp0;
@@ -1168,9 +1109,9 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 
       udp0 = ip4_next_header (ip0);
       icmp0 = (icmp46_header_t *) udp0;
-      proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      proto0 = ip0->protocol;
 
-      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+      if (PREDICT_FALSE (nat44_ed_is_unk_proto (proto0)))
 	{
 	  s0 = nat44_ed_out2in_slowpath_unknown_proto (
 	    sm, b0, ip0, rx_fib_index0, thread_index, now, vm, node);
@@ -1195,7 +1136,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
 	{
 	  next[0] = icmp_out2in_ed_slow_path
 	    (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
@@ -1217,10 +1158,10 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      init_ed_k (&kv0, ip0->src_address,
-		 vnet_buffer (b0)->ip.reass.l4_src_port, ip0->dst_address,
-		 vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
-		 ip0->protocol);
+      init_ed_k (
+	&kv0, ip0->src_address.as_u32, vnet_buffer (b0)->ip.reass.l4_src_port,
+	ip0->dst_address.as_u32, vnet_buffer (b0)->ip.reass.l4_dst_port,
+	rx_fib_index0, ip0->protocol);
 
       s0 = NULL;
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
@@ -1232,7 +1173,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 
 	  if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
 	    {
-	      nat_free_session_data (sm, s0, thread_index, 0);
+	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
 	      nat_ed_session_delete (sm, s0, thread_index, 1);
 	      s0 = NULL;
 	    }
@@ -1253,10 +1194,10 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	       * Send DHCP packets to the ipv4 stack, or we won't
 	       * be able to use dhcp client on the outside interface
 	       */
-	      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_UDP
-				 && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
-				     clib_host_to_net_u16
-				     (UDP_DST_PORT_dhcp_to_client))))
+	      if (PREDICT_FALSE (
+		    proto0 == IP_PROTOCOL_UDP &&
+		    (vnet_buffer (b0)->ip.reass.l4_dst_port ==
+		     clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
 		{
 		  goto trace0;
 		}
@@ -1287,9 +1228,9 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  if (PREDICT_FALSE (identity_nat0))
 	    goto trace0;
 
-	  if ((proto0 == NAT_PROTOCOL_TCP)
-	      && !tcp_flags_is_init (vnet_buffer (b0)->ip.
-				     reass.icmp_type_or_tcp_flags))
+	  if ((proto0 == IP_PROTOCOL_TCP) &&
+	      !tcp_flags_is_init (
+		vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 	    {
 	      b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
 	      next[0] = NAT_NEXT_DROP;
@@ -1297,16 +1238,10 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	    }
 
 	  /* Create session initiated by host from external network */
-	  s0 = create_session_for_static_mapping_ed (sm, b0,
-						     sm_addr, sm_port,
-						     sm_fib_index,
-						     ip0->dst_address,
-						     vnet_buffer (b0)->
-						     ip.reass.l4_dst_port,
-						     rx_fib_index0, proto0,
-						     node, rx_fib_index0,
-						     thread_index, twice_nat0,
-						     lb_nat0, now, m);
+	  s0 = create_session_for_static_mapping_ed (
+	    sm, b0, sm_addr, sm_port, sm_fib_index, ip0->dst_address,
+	    vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0, proto0,
+	    node, thread_index, twice_nat0, lb_nat0, now, m);
 	  if (!s0)
 	    {
 	      next[0] = NAT_NEXT_DROP;
@@ -1322,7 +1257,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+      if (PREDICT_TRUE (proto0 == IP_PROTOCOL_TCP))
 	{
 	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
 					 thread_index, sw_if_index0, 1);
diff --git a/src/plugins/nat/nat44-ei/nat44_ei.c b/src/plugins/nat/nat44-ei/nat44_ei.c
index 2dbef8e34df..3691af3a53e 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei.c
@@ -1102,7 +1102,8 @@ nat44_ei_free_session_data_v2 (nat44_ei_main_t *nm, nat44_ei_session_t *s,
       /* log NAT event */
       nat_ipfix_logging_nat44_ses_delete (
 	thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32,
-	s->nat_proto, s->in2out.port, s->out2in.port, s->in2out.fib_index);
+	nat_proto_to_ip_proto (s->nat_proto), s->in2out.port, s->out2in.port,
+	s->in2out.fib_index);
 
       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
 		   s->ext_host_port, s->nat_proto, s->out2in.fib_index,
@@ -1270,7 +1271,8 @@ nat44_ei_free_session_data (nat44_ei_main_t *nm, nat44_ei_session_t *s,
 
       nat_ipfix_logging_nat44_ses_delete (
 	thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32,
-	s->nat_proto, s->in2out.port, s->out2in.port, s->in2out.fib_index);
+	nat_proto_to_ip_proto (s->nat_proto), s->in2out.port, s->out2in.port,
+	s->in2out.fib_index);
 
       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
 		   s->ext_host_port, s->nat_proto, s->out2in.fib_index,
diff --git a/src/plugins/nat/nat44-ei/nat44_ei.h b/src/plugins/nat/nat44-ei/nat44_ei.h
index 2e5d85f071a..2e95b1413ca 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei.h
+++ b/src/plugins/nat/nat44-ei/nat44_ei.h
@@ -36,6 +36,7 @@
 
 #include <nat/lib/lib.h>
 #include <nat/lib/inlines.h>
+#include <nat/lib/nat_proto.h>
 
 /* default number of worker handoff frame queue elements */
 #define NAT_FQ_NELTS_DEFAULT 64
diff --git a/src/plugins/nat/nat44-ei/nat44_ei_in2out.c b/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
index 1e28ed6b635..a2fc5910584 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
@@ -271,13 +271,10 @@ nat44_i2o_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
       if (clib_bihash_add_del_8_8 (&nm->out2in, &s_kv, 0))
 	nat_elog_warn (nm, "out2in key del failed");
 
-      nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
-					  s->in2out.addr.as_u32,
-					  s->out2in.addr.as_u32,
-					  s->nat_proto,
-					  s->in2out.port,
-					  s->out2in.port,
-					  s->in2out.fib_index);
+      nat_ipfix_logging_nat44_ses_delete (
+	ctx->thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32,
+	nat_proto_to_ip_proto (s->nat_proto), s->in2out.port, s->out2in.port,
+	s->in2out.fib_index);
 
       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
 			       &s->in2out.addr, s->in2out.port,
@@ -430,8 +427,9 @@ slow_path (nat44_ei_main_t *nm, vlib_buffer_t *b0, ip4_header_t *ip0,
 
   /* log NAT event */
   nat_ipfix_logging_nat44_ses_create (
-    thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32, s->nat_proto,
-    s->in2out.port, s->out2in.port, s->in2out.fib_index);
+    thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32,
+    nat_proto_to_ip_proto (s->nat_proto), s->in2out.port, s->out2in.port,
+    s->in2out.fib_index);
 
   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index, &s->in2out.addr,
 			   s->in2out.port, &s->out2in.addr, s->out2in.port,
diff --git a/src/plugins/nat/nat44-ei/nat44_ei_inlines.h b/src/plugins/nat/nat44-ei/nat44_ei_inlines.h
index 672927256d1..399486c77dc 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_inlines.h
+++ b/src/plugins/nat/nat44-ei/nat44_ei_inlines.h
@@ -20,6 +20,7 @@
 
 #include <nat/nat44-ei/nat44_ei.h>
 #include <nat/nat44-ei/nat44_ei_ha.h>
+#include <nat/lib/nat_proto.h>
 
 always_inline u64
 calc_nat_key (ip4_address_t addr, u16 port, u32 fib_index, u8 proto)
@@ -220,6 +221,29 @@ nat44_ei_session_update_counters (nat44_ei_session_t *s, f64 now, uword bytes,
 	       &s->ha_last_refreshed, now);
 }
 
+static_always_inline u32
+nat_session_get_timeout (nat_timeouts_t *timeouts, nat_protocol_t proto,
+			 u8 state)
+{
+  switch (proto)
+    {
+    case NAT_PROTOCOL_ICMP:
+      return timeouts->icmp;
+    case NAT_PROTOCOL_UDP:
+      return timeouts->udp;
+    case NAT_PROTOCOL_TCP:
+      {
+	if (state)
+	  return timeouts->tcp.transitory;
+	else
+	  return timeouts->tcp.established;
+      }
+    default:
+      return timeouts->udp;
+    }
+  return 0;
+}
+
 #endif /* __included_nat44_ei_inlines_h__ */
 
 /*
diff --git a/src/plugins/nat/nat44-ei/nat44_ei_out2in.c b/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
index 7796b11cfd7..7858811fde5 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
@@ -124,13 +124,10 @@ nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
       if (clib_bihash_add_del_8_8 (&nm->in2out, &s_kv, 0))
 	nat_elog_warn (nm, "out2in key del failed");
 
-      nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
-					  s->in2out.addr.as_u32,
-					  s->out2in.addr.as_u32,
-					  s->nat_proto,
-					  s->in2out.port,
-					  s->out2in.port,
-					  s->in2out.fib_index);
+      nat_ipfix_logging_nat44_ses_delete (
+	ctx->thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32,
+	nat_proto_to_ip_proto (s->nat_proto), s->in2out.port, s->out2in.port,
+	s->in2out.fib_index);
 
       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
 			       &s->in2out.addr, s->in2out.port,
@@ -233,12 +230,10 @@ create_session_for_static_mapping (
     nat_elog_notice (nm, "out2in key add failed");
 
   /* log NAT event */
-  nat_ipfix_logging_nat44_ses_create (thread_index,
-				      s->in2out.addr.as_u32,
-				      s->out2in.addr.as_u32,
-				      s->nat_proto,
-				      s->in2out.port,
-				      s->out2in.port, s->in2out.fib_index);
+  nat_ipfix_logging_nat44_ses_create (
+    thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32,
+    nat_proto_to_ip_proto (s->nat_proto), s->in2out.port, s->out2in.port,
+    s->in2out.fib_index);
 
   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
 			   &s->in2out.addr, s->in2out.port, &s->out2in.addr,
diff --git a/src/plugins/nat/nat64/nat64_db.h b/src/plugins/nat/nat64/nat64_db.h
index 711b6bf6b03..c34b671999a 100644
--- a/src/plugins/nat/nat64/nat64_db.h
+++ b/src/plugins/nat/nat64/nat64_db.h
@@ -18,6 +18,7 @@
 #include <vnet/vnet.h>
 #include <vnet/ip/ip.h>
 #include <vnet/fib/fib_source.h>
+#include <nat/lib/nat_proto.h>
 
 #include <vppinfra/bihash_24_8.h>
 #include <vppinfra/bihash_48_8.h>
diff --git a/test/framework.py b/test/framework.py
index aa533f7b641..486553befa1 100755
--- a/test/framework.py
+++ b/test/framework.py
@@ -1304,6 +1304,8 @@ class VppTestCase(CPUInterface, unittest.TestCase):
             n_rx = len(pkts)
         self.pg_send(intf, pkts, worker=worker, trace=trace)
         rx = output.get_capture(n_rx)
+        if trace:
+            self.logger.debug(self.vapi.cli("show trace"))
         return rx
 
     def send_and_expect_only(self, intf, pkts, output, timeout=None):
diff --git a/test/test_nat44_ed.py b/test/test_nat44_ed.py
index ec8d7c8d159..2fb955afa74 100644
--- a/test/test_nat44_ed.py
+++ b/test/test_nat44_ed.py
@@ -19,7 +19,8 @@ from vpp_ip_route import VppIpRoute, VppRoutePath
 from vpp_papi import VppEnum
 
 
-class NAT44EDTestCase(VppTestCase):
+class TestNAT44ED(VppTestCase):
+    """ NAT44ED Test Case """
 
     nat_addr = '10.0.0.3'
 
@@ -37,17 +38,18 @@ class NAT44EDTestCase(VppTestCase):
     max_sessions = 100
 
     def setUp(self):
-        super(NAT44EDTestCase, self).setUp()
+        super().setUp()
         self.plugin_enable()
 
     def tearDown(self):
-        super(NAT44EDTestCase, self).tearDown()
+        super().tearDown()
         if not self.vpp_dead:
             self.plugin_disable()
 
     def plugin_enable(self):
         self.vapi.nat44_ed_plugin_enable_disable(
-            sessions=self.max_sessions, enable=1)
+            sessions=self.max_sessions, enable=1,
+            inside_vrf=0, outside_vrf=1)
 
     def plugin_disable(self):
         self.vapi.nat44_ed_plugin_enable_disable(enable=0)
@@ -146,7 +148,7 @@ class NAT44EDTestCase(VppTestCase):
 
     @classmethod
     def setUpClass(cls):
-        super(NAT44EDTestCase, cls).setUpClass()
+        super().setUpClass()
 
         cls.create_pg_interfaces(range(12))
         cls.interfaces = list(cls.pg_interfaces[:4])
@@ -910,10 +912,6 @@ class NAT44EDTestCase(VppTestCase):
             self.assertEqual(sd_params.get('XDPORT'),
                              "%d" % self.tcp_external_port)
 
-
-class TestNAT44ED(NAT44EDTestCase):
-    """ NAT44ED Test Case """
-
     def test_icmp_error(self):
         """ NAT44ED test ICMP error message with inner header"""
 
@@ -2258,7 +2256,7 @@ class TestNAT44EDMW(TestNAT44ED):
 
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(pkt_count * 3)
+        capture = self.pg1.get_capture(pkt_count * 3, timeout=5)
 
         if_idx = self.pg0.sw_if_index
         tc2 = self.statistics['/nat44-ed/in2out/slowpath/tcp']
diff --git a/test/test_nat44_ed_output.py b/test/test_nat44_ed_output.py
new file mode 100644
index 00000000000..ea5c14e7064
--- /dev/null
+++ b/test/test_nat44_ed_output.py
@@ -0,0 +1,229 @@
+#!/usr/bin/env python3
+"""NAT44 ED output-feature tests"""
+
+import random
+import unittest
+from scapy.layers.inet import ICMP, Ether, IP, TCP
+from scapy.packet import Raw
+from scapy.data import IP_PROTOS
+from framework import VppTestCase, VppTestRunner
+from vpp_papi import VppEnum
+
+
+def get_nat44_ed_in2out_worker_index(ip, vpp_worker_count):
+    if 0 == vpp_worker_count:
+        return 0
+    numeric = socket.inet_aton(ip)
+    numeric = struct.unpack("!L", numeric)[0]
+    numeric = socket.htonl(numeric)
+    h = numeric + (numeric >> 8) + (numeric >> 16) + (numeric >> 24)
+    return 1 + h % vpp_worker_count
+
+
+class TestNAT44EDOutput(VppTestCase):
+    """ NAT44 ED output feature Test Case """
+    max_sessions = 1024
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.create_pg_interfaces(range(2))
+        cls.interfaces = list(cls.pg_interfaces)
+
+    @classmethod
+    def tearDownClass(cls):
+        super().tearDownClass()
+
+    def setUp(self):
+        super().setUp()
+        for i in self.interfaces:
+            i.admin_up()
+            i.config_ip4()
+            i.resolve_arp()
+        self.vapi.nat44_ed_plugin_enable_disable(sessions=self.max_sessions,
+                                                 enable=1)
+
+    def tearDown(self):
+        if not self.vpp_dead:
+            self.logger.debug(self.vapi.cli("show nat44 sessions"))
+        super().tearDown()
+        if not self.vpp_dead:
+            for i in self.pg_interfaces:
+                i.unconfig_ip4()
+                i.admin_down()
+            self.vapi.nat44_ed_plugin_enable_disable(enable=0)
+
+    def test_static_dynamic(self):
+        """ Create static mapping which matches existing dynamic mapping """
+
+        old_timeouts = self.vapi.nat_get_timeouts()
+        new_transitory = 2
+        self.vapi.nat_set_timeouts(
+            udp=old_timeouts.udp,
+            tcp_established=old_timeouts.tcp_established,
+            icmp=old_timeouts.icmp,
+            tcp_transitory=new_transitory)
+
+        local_host = self.pg0.remote_ip4
+        remote_host = self.pg1.remote_ip4
+        nat_intf = self.pg1
+        outside_addr = nat_intf.local_ip4
+
+        self.vapi.nat44_add_del_address_range(first_ip_address=outside_addr,
+                                              last_ip_address=outside_addr,
+                                              vrf_id=0xffffffff,
+                                              is_add=1,
+                                              flags=0)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=VppEnum.vl_api_nat_config_flags_t.NAT_IS_INSIDE, is_add=1)
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1,
+            sw_if_index=self.pg1.sw_if_index)
+
+        thread_index = get_nat44_ed_in2out_worker_index(
+            local_host, self.vpp_worker_count)
+        port_per_thread = int((0xffff-1024) / max(1, self.vpp_worker_count))
+        local_sport = 1024 + random.randint(1, port_per_thread)
+        if self.vpp_worker_count > 0:
+            local_sport += port_per_thread * (thread_index - 1)
+
+        remote_dport = 10000
+
+        pg0 = self.pg0
+        pg1 = self.pg1
+
+        # first setup a dynamic TCP session
+
+        # SYN packet in->out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="S"))
+        p = self.send_and_expect(pg0, [p], pg1)[0]
+
+        self.assertEqual(p[IP].src, outside_addr)
+        self.assertEqual(p[TCP].sport, local_sport)
+        outside_port = p[TCP].sport
+
+        # SYN+ACK packet out->in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port, flags="SA"))
+        self.send_and_expect(pg1, [p], pg0)
+
+        # ACK packet in->out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="A"))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # now we have a session up, create a conflicting static mapping
+        self.vapi.nat44_add_del_static_mapping(
+            is_add=1,
+            local_ip_address=local_host,
+            external_ip_address=outside_addr,
+            external_sw_if_index=0xffffffff,
+            local_port=local_sport,
+            external_port=outside_port,
+            protocol=IP_PROTOS.tcp,
+            flags=VppEnum.vl_api_nat_config_flags_t.NAT_IS_OUT2IN_ONLY)
+
+        sessions = self.vapi.nat44_user_session_dump(local_host, 0)
+        self.assertEqual(1, len(sessions))
+
+        # now send some more data over existing session - it should pass
+
+        # in->out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport) /
+             Raw("zippity zap"))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # out->in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port) /
+             Raw("flippity flop"))
+        self.send_and_expect(pg1, [p], pg0)
+
+        # now close the session
+
+        # FIN packet in -> out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="FA", seq=100,
+                 ack=300))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # FIN+ACK packet out -> in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port, flags="FA", seq=300,
+                 ack=101))
+        self.send_and_expect(pg1, [p], pg0)
+
+        # ACK packet in -> out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="A", seq=101,
+                 ack=301))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # session now in transitory timeout
+        # try SYN packet in->out - should be dropped
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="S"))
+        pg0.add_stream(p)
+        self.pg_enable_capture()
+        self.pg_start()
+
+        self.sleep(new_transitory, "wait for transitory timeout")
+        pg0.assert_nothing_captured(0)
+
+        # session should still exist
+        sessions = self.vapi.nat44_user_session_dump(pg0.remote_ip4, 0)
+        self.assertEqual(1, len(sessions))
+
+        # send FIN+ACK packet in->out - will cause session to be wiped
+        # but won't create a new session
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="FA", seq=300,
+                 ack=101))
+        pg1.add_stream(p)
+        self.pg_enable_capture()
+        self.pg_start()
+        pg0.assert_nothing_captured(0)
+
+        sessions = self.vapi.nat44_user_session_dump(pg0.remote_ip4, 0)
+        self.assertEqual(0, len(sessions))
+
+        # create a new session and make sure the outside port is remapped
+        # SYN packet in->out
+
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="S"))
+        p = self.send_and_expect(pg0, [p], pg1)[0]
+
+        self.assertEqual(p[IP].src, outside_addr)
+        self.assertNotEqual(p[TCP].sport, local_sport)
+
+        # make sure static mapping works and creates a new session
+        # SYN packet out->in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port, flags="S"))
+        self.send_and_expect(pg1, [p], pg0)
+
+        sessions = self.vapi.nat44_user_session_dump(pg0.remote_ip4, 0)
+        self.assertEqual(2, len(sessions))
+
+
+if __name__ == '__main__':
+    unittest.main(testRunner=VppTestRunner)
diff --git a/test/test_nat44_ei.py b/test/test_nat44_ei.py
index 74a082eee0a..5fdcf3fa3c7 100644
--- a/test/test_nat44_ei.py
+++ b/test/test_nat44_ei.py
@@ -605,7 +605,7 @@ class MethodHolder(VppTestCase):
                 self.assertEqual(struct.pack("!H", self.udp_port_out),
                                  record[227])
             else:
-                self.fail("Invalid protocol")
+                self.fail(f"Invalid protocol {scapy.compat.orb(record[4])}")
         self.assertEqual(3, nat44_ses_create_num)
         self.assertEqual(3, nat44_ses_delete_num)