Revert "nat: static mappings in flow hash"

This reverts commit 69b7599e4b061a8996205f0304232ede84cb70d4.

Type: fix
Signed-off-by: Ole Troan <ot@cisco.com>
Change-Id: If531b122ae5a9f91c2fe6eaa0da69922a91f16d3

10 files changed, 1195 insertions, 850 deletions

diff --git a/src/plugins/nat/nat44-ed/nat44_ed.c b/src/plugins/nat/nat44-ed/nat44_ed.c
index d639392019b..a11043682b9 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed.c
@@ -28,11 +28,9 @@
 #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>
@@ -185,6 +183,29 @@ 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 *);
@@ -206,81 +227,59 @@ format_ed_session_kvp (u8 * s, va_list * args)
   return s;
 }
 
-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)
+void
+nat_free_session_data (snat_main_t * sm, snat_session_t * s, u32 thread_index,
+		       u8 is_ha)
 {
-  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*/);
-}
+      per_vrf_sessions_unregister_session (s, thread_index);
 
-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_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_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 (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_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 (na44_ed_is_fwd_bypass_session (s))
+	{
+	  return;
+	}
 
-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 (nat44_ed_is_affinity_session (s))
+	nat_affinity_unlock (s->ext_host_addr, s->out2in.addr, s->nat_proto,
+			     s->out2in.port);
 
-  if (nat_ed_ses_i2o_flow_hash_add_del (sm, thread_index, s, 0))
-    nat_elog_warn (sm, "flow hash del failed");
+      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_o2i_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 (na44_ed_is_fwd_bypass_session (s))
-    {
-      return;
-    }
+      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 (nat44_ed_is_affinity_session (s))
-    nat_affinity_unlock (s->ext_host_addr, s->out2in.addr, s->proto,
-			 s->out2in.port);
+  /* 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 (!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));
+      if (nat44_ed_is_session_static (s))
+	return;
 
-  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);
-    }
+      snat_free_outside_address_and_port (sm->addresses, thread_index,
+					  &s->out2in.addr, s->out2in.port,
+					  s->nat_proto);
 }
 
 static int
@@ -389,6 +388,7 @@ 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;
@@ -426,6 +426,16 @@ 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
@@ -470,8 +480,7 @@ 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,
-					   ip_proto_to_nat_proto (m->proto),
-					   m->vrf_id, ~0, m->flags);
+					   m->proto, m->vrf_id, ~0, m->flags);
 	    }
 	}
     }
@@ -492,25 +501,32 @@ nat44_ed_del_address (ip4_address_t addr, u8 delete_sm, u8 twice_nat)
     }
 
   // delete sessions using address
-  vec_foreach (tsm, sm->per_thread_data)
+  if (a->busy_tcp_ports || a->busy_udp_ports || a->busy_icmp_ports)
     {
-      pool_foreach (ses, tsm->sessions)
+      vec_foreach (tsm, sm->per_thread_data)
 	{
-	  if (ses->out2in.addr.as_u32 == addr.as_u32)
+	  pool_foreach (ses, tsm->sessions)
 	    {
-	      nat44_ed_free_session_data (sm, ses, tsm - sm->per_thread_data,
-					  0);
-	      vec_add1 (ses_to_be_removed, 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)
+	    {
+	      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);
 	}
-      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);
@@ -553,17 +569,18 @@ 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->proto != protocol)
-	  continue;
+        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 (nat44_ed_is_lb_session (s))
       continue;
     if (!nat44_ed_is_session_static (s))
       continue;
-    nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+    nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
     vec_add1 (indexes_to_free, s - tsm->sessions);
     if (!addr_only)
       break;
@@ -577,41 +594,89 @@ nat_ed_static_mapping_del_sessions (snat_main_t * sm,
   vec_free (indexes_to_free);
 }
 
-static_always_inline snat_static_mapping_t *
-nat44_ed_sm_lookup (snat_main_t *sm, clib_bihash_kv_16_8_t *kv)
+int
+nat44_ed_reserve_port (ip4_address_t addr, u16 port, nat_protocol_t proto)
 {
-  clib_bihash_kv_16_8_t v;
-  int rc = clib_bihash_search_16_8 (&sm->flow_hash, kv, &v);
-  if (!rc)
+  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++)
     {
-      ASSERT (0 == ed_value_get_thread_index (&v));
-      return pool_elt_at_index (sm->static_mappings,
-				ed_value_get_session_index (&v));
+      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;
     }
-  return NULL;
-}
 
-snat_static_mapping_t *
-nat44_ed_sm_o2i_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_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)
+int
+nat44_ed_free_port (ip4_address_t addr, u16 port, nat_protocol_t 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);
+  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;
+    }
+
+done:
+  return 1;
 }
 
 void
 nat44_ed_add_resolve_record (ip4_address_t l_addr, u16 l_port, u16 e_port,
-			     ip_protocol_t proto, u32 vrf_id, u32 sw_if_index,
+			     nat_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;
@@ -631,7 +696,7 @@ 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,
-			     ip_protocol_t proto, u32 vrf_id, u32 sw_if_index,
+			     nat_protocol_t proto, u32 vrf_id, u32 sw_if_index,
 			     u32 flags, int *out)
 {
   snat_static_map_resolve_t *rp;
@@ -681,7 +746,7 @@ 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,
-			     ip_protocol_t proto, u32 vrf_id, u32 sw_if_index,
+			     nat_protocol_t proto, u32 vrf_id, u32 sw_if_index,
 			     u32 flags)
 {
   snat_main_t *sm = &snat_main;
@@ -714,24 +779,14 @@ 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, ip_protocol_t proto,
+			     u16 l_port, u16 e_port, nat_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;
@@ -785,9 +840,12 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       l_addr.as_u32 = e_addr.as_u32;
     }
 
-  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
-  if (m)
+  // 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 = pool_elt_at_index (sm->static_mappings, value.value);
       if (!is_sm_identity_nat (m->flags))
 	{
 	  return VNET_API_ERROR_VALUE_EXIST;
@@ -809,8 +867,9 @@ 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);
 
-      nat44_ed_sm_i2o_add (sm, m, m->local_addr, m->local_port,
-			   local->fib_index, m->proto);
+      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);
 
       return 0;
     }
@@ -832,7 +891,8 @@ 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)))
     {
-      if (nat44_ed_sm_i2o_lookup (sm, l_addr, l_port, fib_index, proto))
+      init_nat_k (&kv, l_addr, l_port, fib_index, proto);
+      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
 	{
 	  return VNET_API_ERROR_VALUE_EXIST;
 	}
@@ -841,7 +901,7 @@ 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_addr_lookup (sm, e_addr.as_u32))
+      if (nat44_ed_reserve_port (e_addr, e_port, proto))
 	{
 	  // remove resolve record
 	  if (is_sm_switch_address (flags) && !is_sm_identity_nat (flags))
@@ -895,11 +955,14 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
   if (!is_sm_out2in_only (flags))
     {
-      nat44_ed_sm_i2o_add (sm, m, m->local_addr, m->local_port, fib_index,
-			   m->proto);
+      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_o2i_add (sm, m, m->external_addr, m->external_port, 0, 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);
 
   if (sm->num_workers > 1)
     {
@@ -918,12 +981,13 @@ 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, ip_protocol_t proto,
+			     u16 l_port, u16 e_port, nat_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;
@@ -975,9 +1039,9 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     }
 
   // fib index 0
-  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
+  init_nat_k (&kv, e_addr, e_port, 0, proto);
 
-  if (!m)
+  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
     {
       if (is_sm_switch_address (flags))
 	{
@@ -986,6 +1050,8 @@ 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;
@@ -1019,7 +1085,7 @@ 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_addr_lookup (sm, e_addr.as_u32))
+      if (nat44_ed_free_port (e_addr, e_port, proto))
 	{
 	  return VNET_API_ERROR_INVALID_VALUE;
 	}
@@ -1027,7 +1093,8 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
   if (!is_sm_out2in_only (flags))
     {
-      nat44_ed_sm_i2o_del (sm, l_addr, l_port, fib_index, proto);
+      init_nat_k (&kv, l_addr, l_port, fib_index, proto);
+      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0);
     }
 
   if (!sm->static_mapping_only || sm->static_mapping_connection_tracking)
@@ -1049,7 +1116,8 @@ 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
-      nat44_ed_sm_o2i_del (sm, e_addr, e_port, 0, proto);
+      init_nat_k (&kv, e_addr, e_port, 0, proto);
+      clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0);
 
       vec_free (m->tag);
       vec_free (m->workers);
@@ -1066,17 +1134,17 @@ 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,
-				ip_protocol_t proto,
+				nat_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;
 
@@ -1085,7 +1153,15 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       return VNET_API_ERROR_UNSUPPORTED;
     }
 
-  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
+  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);
+    }
 
   if (m)
     {
@@ -1105,11 +1181,25 @@ 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)
 	    {
-	      /* External port must be unused */
 	      a = sm->addresses + i;
-	      if (nat44_ed_sm_o2i_lookup (sm, a->addr, e_port, 0, proto))
+	      /* External port must be unused */
+	      switch (proto)
 		{
-		  return VNET_API_ERROR_VALUE_EXIST;
+#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;
 		}
 	      break;
 	    }
@@ -1138,10 +1228,11 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
   else
     m->affinity_per_service_list_head_index = ~0;
 
-  if (nat44_ed_sm_o2i_add (sm, m, m->external_addr, m->external_port, 0,
-			   m->proto))
+  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))
     {
-      nat_elog_err (sm, "sm o2i key add failed");
+      nat_elog_err (sm, "static_mapping_by_external key add failed");
       return VNET_API_ERROR_UNSPECIFIED;
     }
 
@@ -1151,16 +1242,10 @@ 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))
 	{
-	  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
-	    }
+	  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);
 	}
       locals[i].prefix = (i == 0) ?
 			   locals[i].probability :
@@ -1187,36 +1272,72 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	}
     }
 
-  return rc;
+  return 0;
 }
 
 int
 nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
-				ip_protocol_t proto, u32 flags)
+				nat_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;
     }
 
-  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
+  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);
+
   if (!m)
     return VNET_API_ERROR_NO_SUCH_ENTRY;
 
   if (!is_sm_lb (m->flags))
     return VNET_API_ERROR_INVALID_VALUE;
 
-  if (nat44_ed_sm_o2i_del (sm, m->external_addr, m->external_port, 0,
-			   m->proto))
+  if (!(sm->static_mapping_only || is_sm_out2in_only (flags)))
     {
-      nat_elog_err (sm, "sm o2i key del failed");
+      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");
       return VNET_API_ERROR_UNSPECIFIED;
     }
 
@@ -1225,10 +1346,11 @@ 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))
 	{
-	  if (nat44_ed_sm_i2o_del (sm, local->addr, local->port,
-				   local->fib_index, m->proto))
+	  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))
 	    {
-	      nat_elog_err (sm, "sm i2o key del failed");
+	      nat_elog_err (sm, "static_mapping_by_local key del failed");
 	      return VNET_API_ERROR_UNSPECIFIED;
 	    }
 	}
@@ -1255,7 +1377,7 @@ nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	      s->in2out.port != local->port)
 	    continue;
 
-	  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+	  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
 	  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
 	}
     }
@@ -1276,11 +1398,12 @@ 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,
-					  ip_protocol_t proto, u32 vrf_id,
+					  nat_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;
@@ -1293,7 +1416,9 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
       return VNET_API_ERROR_UNSUPPORTED;
     }
 
-  m = nat44_ed_sm_o2i_lookup (sm, e_addr, e_port, 0, proto);
+  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);
 
   if (!m)
     {
@@ -1334,13 +1459,10 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 
       if (!is_sm_out2in_only (m->flags))
 	{
-	  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;
-	    }
+	  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");
 	}
     }
   else
@@ -1356,9 +1478,9 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 
       if (!is_sm_out2in_only (m->flags))
 	{
-	  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");
+	  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 (sm->num_workers > 1)
@@ -1382,7 +1504,7 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 	      s->in2out.port != match_local->port)
 	    continue;
 
-	  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+	  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
 	  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
       }
 
@@ -2041,8 +2163,8 @@ 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.as_u32, l_port, r_addr.as_u32, r_port, fib_index,
-	      proto, thread_index, session_index);
+  init_ed_kv (&kv, l_addr, l_port, r_addr, 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));
@@ -2061,6 +2183,16 @@ 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 *
@@ -2309,6 +2441,14 @@ 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;
 }
@@ -2408,7 +2548,7 @@ 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]);
-	  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+	  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
 	  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
 	}
 
@@ -2416,87 +2556,87 @@ nat44_ed_forwarding_enable_disable (u8 is_enable)
     }
 }
 
-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)
+void
+snat_free_outside_address_and_port (snat_address_t *addresses,
+				    u32 thread_index, ip4_address_t *addr,
+				    u16 port, nat_protocol_t protocol)
 {
-  snat_static_mapping_t *m;
-  if (!by_external)
-    {
-      m = nat44_ed_sm_i2o_lookup (sm, match_addr, match_port, match_fib_index,
-				  match_protocol);
-      if (m)
-	return m;
+  snat_main_t *sm = &snat_main;
+  snat_address_t *a;
+  u32 address_index;
+  u16 port_host_byte_order = clib_net_to_host_u16 (port);
 
-      /* Try address only mapping */
-      m = nat44_ed_sm_i2o_lookup (sm, match_addr, 0, match_fib_index, 0);
-      if (m)
-	return m;
+  for (address_index = 0; address_index < vec_len (addresses);
+       address_index++)
+    {
+      if (addresses[address_index].addr.as_u32 == addr->as_u32)
+	break;
+    }
 
-      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;
+  ASSERT (address_index < vec_len (addresses));
 
-	  /* 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;
+  a = addresses + address_index;
 
-	  /* Try address only mapping */
-	  m = nat44_ed_sm_i2o_lookup (sm, match_addr, 0, sm->outside_fib_index,
-				      0);
-	  if (m)
-	    return m;
-	}
-    }
-  else
+  switch (protocol)
     {
-      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;
+#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;
     }
-  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, ip_protocol_t match_protocol,
+			   u32 match_fib_index, nat_protocol_t match_protocol,
 			   ip4_address_t *mapping_addr, u16 *mapping_port,
-			   u32 *mapping_fib_index, int by_external,
+			   u32 *mapping_fib_index, u8 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;
 
-  m = nat44_ed_sm_match (sm, match_addr, match_port, match_fib_index,
-			 match_protocol, by_external);
-  if (!m)
+  if (!by_external)
     {
-      return 1;
+      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
+    {
+      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;
+	}
+    }
+
+  m = pool_elt_at_index (sm->static_mappings, value.value);
 
   if (by_external)
     {
@@ -2674,9 +2814,8 @@ 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.as_u32, lookup_sport,
-			 lookup_daddr.as_u32, lookup_dport, rx_fib_index,
-			 lookup_protocol);
+	      init_ed_k (&kv16, lookup_saddr, lookup_sport, lookup_daddr,
+			 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);
@@ -2687,10 +2826,9 @@ nat44_ed_get_in2out_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	    }
 	}
 
-      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);
+      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);
 
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16))
 	{
@@ -2701,10 +2839,9 @@ nat44_ed_get_in2out_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	}
 
       // dst NAT
-      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);
+      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);
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16))
 	{
 	  next_worker_index = ed_value_get_thread_index (&value16);
@@ -2746,16 +2883,17 @@ 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;
 
-  u8 proto, next_worker_index = 0;
+  u32 proto, next_worker_index = 0;
   u16 port;
   snat_static_mapping_t *m;
   u32 hash;
 
-  proto = ip->protocol;
+  proto = ip_proto_to_nat_proto (ip->protocol);
 
-  if (PREDICT_FALSE (IP_PROTOCOL_ICMP == proto))
+  if (PREDICT_FALSE (proto == NAT_PROTOCOL_ICMP))
     {
       ip4_address_t lookup_saddr, lookup_daddr;
       u16 lookup_sport, lookup_dport;
@@ -2764,9 +2902,8 @@ 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.as_u32, lookup_sport,
-		     lookup_daddr.as_u32, lookup_dport, rx_fib_index,
-		     lookup_protocol);
+	  init_ed_k (&kv16, lookup_saddr, lookup_sport, lookup_daddr,
+		     lookup_dport, rx_fib_index, lookup_protocol);
 	  if (PREDICT_TRUE (
 		!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16)))
 	    {
@@ -2780,10 +2917,9 @@ nat44_ed_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip,
 	}
     }
 
-  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);
+  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);
 
   if (PREDICT_TRUE (
 	!clib_bihash_search_16_8 (&sm->flow_hash, &kv16, &value16)))
@@ -2801,18 +2937,18 @@ 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)))
     {
-      m = nat44_ed_sm_o2i_lookup (sm, ip->dst_address, 0, 0, proto);
-      if (m)
+      init_nat_k (&kv, ip->dst_address, 0, 0, 0);
+      if (!clib_bihash_search_8_8
+	  (&sm->static_mapping_by_external, &kv, &value))
 	{
-	  {
-	    next_worker_index = m->workers[0];
-	    goto done;
-	  }
+	  m = pool_elt_at_index (sm->static_mappings, value.value);
+	  next_worker_index = m->workers[0];
+	  goto done;
 	}
     }
 
   /* unknown protocol */
-  if (PREDICT_FALSE (nat44_ed_is_unk_proto (proto)))
+  if (PREDICT_FALSE (proto == NAT_PROTOCOL_OTHER))
     {
       /* use current thread */
       next_worker_index = vlib_get_thread_index ();
@@ -2833,18 +2969,17 @@ 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 = inner_ip->protocol;
+	  proto = ip_proto_to_nat_proto (inner_ip->protocol);
 	  void *l4_header = ip4_next_header (inner_ip);
 	  switch (proto)
 	    {
-	    case IP_PROTOCOL_ICMP:
+	    case NAT_PROTOCOL_ICMP:
 	      icmp = (icmp46_header_t *) l4_header;
 	      echo = (icmp_echo_header_t *) (icmp + 1);
 	      port = echo->identifier;
 	      break;
-	    case IP_PROTOCOL_UDP:
-	      /* breakthrough */
-	    case IP_PROTOCOL_TCP:
+	    case NAT_PROTOCOL_UDP:
+	    case NAT_PROTOCOL_TCP:
 	      port = ((tcp_udp_header_t *) l4_header)->src_port;
 	      break;
 	    default:
@@ -2857,9 +2992,11 @@ 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)))
     {
-      m = nat44_ed_sm_o2i_lookup (sm, ip->dst_address, port, 0, proto);
-      if (m)
+      init_nat_k (&kv, ip->dst_address, 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);
 	  if (!is_sm_lb (m->flags))
 	    {
 	      next_worker_index = m->workers[0];
@@ -2989,9 +3126,23 @@ 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)
@@ -3018,6 +3169,8 @@ 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)
     {
@@ -3054,6 +3207,7 @@ 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;
@@ -3079,8 +3233,17 @@ nat44_ed_add_del_static_mapping_addr_only_cb (
       return;
     }
 
-  m = nat44_ed_sm_o2i_lookup (sm, *address, rp->addr_only ? 0 : rp->e_port, 0,
-			      rp->proto);
+  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);
+    }
 
   if (is_delete)
     {
@@ -3323,8 +3486,7 @@ 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->as_u32, port, eh_addr->as_u32, eh_port, fib_index,
-	     proto);
+  init_ed_k (&kv, *addr, port, *eh_addr, eh_port, fib_index, proto);
   if (clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     {
       return VNET_API_ERROR_NO_SUCH_ENTRY;
@@ -3333,7 +3495,7 @@ 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));
-  nat44_ed_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+  nat_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;
 }
@@ -3439,13 +3601,13 @@ 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, ip_protocol_t proto,
+			   nat_6t_flow_t *f, nat_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 ((IP_PROTOCOL_TCP == proto || IP_PROTOCOL_UDP == proto) &&
+  if ((NAT_PROTOCOL_TCP == proto || NAT_PROTOCOL_UDP == proto) &&
       !vnet_buffer (b)->ip.reass.is_non_first_fragment)
     {
       if (!is_icmp_inner_ip4)
@@ -3463,7 +3625,7 @@ nat_6t_flow_ip4_translate (snat_main_t *sm, vlib_buffer_t *b, ip4_header_t *ip,
 	  udp->dst_port = f->rewrite.sport;
 	}
 
-      if (IP_PROTOCOL_TCP == proto)
+      if (NAT_PROTOCOL_TCP == proto)
 	{
 	  ip_csum_t tcp_sum = tcp->checksum;
 	  tcp_sum = ip_csum_sub_even (tcp_sum, f->l3_csum_delta);
@@ -3471,7 +3633,7 @@ 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 (IP_PROTOCOL_UDP == proto && udp->checksum)
+      else if (proto == NAT_PROTOCOL_UDP && udp->checksum)
 	{
 	  ip_csum_t udp_sum = udp->checksum;
 	  udp_sum = ip_csum_sub_even (udp_sum, f->l3_csum_delta);
@@ -3569,7 +3731,8 @@ 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;
 	    }
 
-	  ip_protocol_t inner_proto = inner_ip->protocol;
+	  nat_protocol_t inner_proto =
+	    ip_proto_to_nat_proto (inner_ip->protocol);
 
 	  ip_csum_t old_icmp_sum = icmp->checksum;
 	  ip_csum_t old_inner_ip_sum = inner_ip->checksum;
@@ -3581,7 +3744,7 @@ nat_6t_flow_icmp_translate (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
 
 	  switch (inner_proto)
 	    {
-	    case IP_PROTOCOL_UDP:
+	    case NAT_PROTOCOL_UDP:
 	      udp = (udp_header_t *) (inner_ip + 1);
 	      if (!it_fits (vm, b, udp, sizeof (*udp)))
 		{
@@ -3602,7 +3765,7 @@ 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 IP_PROTOCOL_TCP:
+	    case NAT_PROTOCOL_TCP:
 	      tcp = (tcp_header_t *) (inner_ip + 1);
 	      if (!it_fits (vm, b, tcp, sizeof (*tcp)))
 		{
@@ -3623,7 +3786,7 @@ 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 IP_PROTOCOL_ICMP:
+	    case NAT_PROTOCOL_ICMP:
 	      if (f->ops & NAT_FLOW_OP_ICMP_ID_REWRITE)
 		{
 		  icmp46_header_t *inner_icmp = ip4_next_header (inner_ip);
@@ -3662,7 +3825,7 @@ 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,
-			   ip_protocol_t proto, int is_output_feature,
+			   nat_protocol_t proto, int is_output_feature,
 			   int is_i2o)
 {
   if (!is_output_feature && f->ops & NAT_FLOW_OP_TXFIB_REWRITE)
@@ -3670,7 +3833,7 @@ 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 (IP_PROTOCOL_ICMP == proto)
+  if (NAT_PROTOCOL_ICMP == proto)
     {
       if (ip->src_address.as_u32 != f->rewrite.saddr.as_u32)
 	{
@@ -3698,7 +3861,7 @@ 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, ip_protocol_t proto,
+			       nat_6t_flow_t *f, nat_protocol_t proto,
 			       int is_output_feature)
 {
   return nat_6t_flow_buf_translate (vm, sm, b, ip, f, proto, is_output_feature,
@@ -3708,7 +3871,7 @@ 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, ip_protocol_t proto,
+			       nat_6t_flow_t *f, nat_protocol_t proto,
 			       int is_output_feature)
 {
   return nat_6t_flow_buf_translate (vm, sm, b, ip, f, proto, is_output_feature,
@@ -3818,81 +3981,6 @@ 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 4665f7c0966..e2f5810f9b0 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed.h
+++ b/src/plugins/nat/nat44-ed/nat44_ed.h
@@ -39,11 +39,6 @@
 /* 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)
 
@@ -177,6 +172,7 @@ 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)
@@ -312,7 +308,7 @@ typedef CLIB_PACKED(struct
     u16 port;
   } in2out;
 
-  ip_protocol_t proto;
+  nat_protocol_t nat_proto;
 
   nat_6t_flow_t i2o;
   nat_6t_flow_t o2i;
@@ -360,6 +356,12 @@ 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
@@ -424,7 +426,7 @@ typedef struct
   u32 vrf_id;
   u32 fib_index;
   /* protocol */
-  ip_protocol_t proto;
+  nat_protocol_t proto;
   /* 0 = disabled, otherwise client IP affinity sticky time in seconds */
   u32 affinity;
   /* worker threads used by backends/local host */
@@ -453,7 +455,7 @@ typedef struct
   u16 e_port;
   u32 sw_if_index;
   u32 vrf_id;
-  ip_protocol_t proto;
+  nat_protocol_t proto;
   u32 flags;
   int addr_only;
   int twice_nat;
@@ -498,10 +500,15 @@ 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,
-  ip_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,
+						      nat_protocol_t proto,
+						      ip4_address_t * addr,
+						      u16 * port,
+						      u16 port_per_thread,
+						      u32 snat_thread_index);
 
 typedef struct snat_main_s
 {
@@ -514,6 +521,12 @@ 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;
 
@@ -702,8 +715,12 @@ 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
@@ -715,6 +732,16 @@ 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
@@ -883,25 +910,25 @@ 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, ip_protocol_t proto,
+				 u16 l_port, u16 e_port, nat_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, ip_protocol_t proto,
+				 u16 l_port, u16 e_port, nat_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,
-				    ip_protocol_t proto,
+				    nat_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,
-				    ip_protocol_t proto, u32 flags);
+				    nat_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,
-					      ip_protocol_t proto, u32 vrf_id,
+					      nat_protocol_t proto, u32 vrf_id,
 					      u8 probability, u8 is_add);
 
 /**
@@ -920,8 +947,16 @@ 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);
 
-void nat44_ed_free_session_data (snat_main_t *sm, snat_session_t *s,
-				 u32 thread_index, u8 is_ha);
+/**
+ * @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);
 
 /**
  * @brief Set NAT44 session limit (session limit, vrf id)
@@ -941,6 +976,19 @@ 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);
 
 /**
@@ -963,9 +1011,9 @@ 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, ip_protocol_t match_protocol,
+  u32 match_fib_index, nat_protocol_t match_protocol,
   ip4_address_t *mapping_addr, u16 *mapping_port, u32 *mapping_fib_index,
-  int by_external, u8 *is_addr_only, twice_nat_type_t *twice_nat,
+  u8 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);
 
@@ -1012,11 +1060,11 @@ 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, ip_protocol_t proto, int is_output_feature);
+  nat_6t_flow_t *f, nat_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, ip_protocol_t proto, int is_output_feature);
+  nat_6t_flow_t *f, nat_protocol_t proto, int is_output_feature);
 
 void nat_6t_l3_l4_csum_calc (nat_6t_flow_t *f);
 
@@ -1024,26 +1072,6 @@ 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 178671c6b7e..89f11c64ef3 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_affinity.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_affinity.c
@@ -37,9 +37,10 @@ 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_ip_protocol, k.proto);
+	      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);
 
   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 d37c2855158..ad00d11052b 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;
-  ip_protocol_t proto = 0;
+  nat_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 = mp->protocol;
+      proto = ip_proto_to_nat_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;
-  ip_protocol_t proto;
+  nat_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 = mp->protocol;
+  proto = ip_proto_to_nat_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 = m->proto;
+      rmp->protocol = nat_proto_to_ip_proto (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 = m->proto;
+      rmp->protocol = nat_proto_to_ip_proto (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;
-  ip_protocol_t proto = 0;
+  nat_protocol_t proto = 0;
   u16 port = 0;
   u8 *tag = 0;
 
@@ -911,7 +911,7 @@ static void
   else
     {
       port = mp->port;
-      proto = mp->protocol;
+      proto = ip_proto_to_nat_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 = m->proto;
+  rmp->protocol = nat_proto_to_ip_proto (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 = m->proto;
+  rmp->protocol = nat_proto_to_ip_proto (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;
-  ip_protocol_t proto;
+  nat_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 = mp->protocol;
+  proto = ip_proto_to_nat_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;
-  ip_protocol_t proto;
+  nat_protocol_t proto;
 
   clib_memcpy (&e_addr, mp->external_addr, 4);
   clib_memcpy (&l_addr, mp->local.addr, 4);
-  proto = mp->protocol;
+  proto = ip_proto_to_nat_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 = m->proto;
+  rmp->protocol = nat_proto_to_ip_proto (m->proto);
   rmp->context = context;
 
   if (is_sm_self_twice_nat (m->flags))
@@ -1740,16 +1740,25 @@ 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;
-  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))
+  if (snat_is_unk_proto_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;
+      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 (nat_proto_to_ip_proto (s->nat_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))
+	{
+	  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 229cf3669e6..5a9f4e42657 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_classify.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_classify.c
@@ -98,6 +98,7 @@ 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];
@@ -121,19 +122,23 @@ 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 */
-	      m = nat44_ed_sm_o2i_lookup (sm, ip0->dst_address, 0, 0, 0);
-	      if (m)
+	      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external,
+					   &kv0, &value0))
 		{
+		  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;
 		}
-	      m = nat44_ed_sm_o2i_lookup (
-		sm, ip0->dst_address, vnet_buffer (b0)->ip.reass.l4_dst_port,
-		0, ip0->protocol);
-	      if (m)
+	      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 = 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;
 		}
@@ -197,6 +202,7 @@ 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 */
@@ -221,11 +227,11 @@ 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.as_u32,
+	      init_ed_k (&ed_kv0, ip0->src_address,
 			 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);
+			 ip0->dst_address,
+			 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))
@@ -266,19 +272,23 @@ 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 */
-	      m = nat44_ed_sm_o2i_lookup (sm, ip0->dst_address, 0, 0, 0);
-	      if (m)
+	      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external,
+					   &kv0, &value0))
 		{
+		  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;
 		}
-	      m = nat44_ed_sm_o2i_lookup (
-		sm, ip0->dst_address, vnet_buffer (b0)->ip.reass.l4_dst_port,
-		0, ip0->protocol);
-	      if (m)
+	      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 = 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 5ab14a6729a..413c7959962 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_cli.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_cli.c
@@ -283,7 +283,12 @@ 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_16_8, &sm->flow_hash, verbose);
+  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);
   vec_foreach_index (i, sm->per_thread_data)
   {
     vlib_cli_output (vm, "-------- thread %d %s --------\n",
@@ -291,7 +296,8 @@ 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);
@@ -496,7 +502,6 @@ 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;
@@ -521,42 +526,40 @@ nat44_show_summary_command_fn (vlib_main_t * vm, unformat_input_t * input,
             if (now >= sess_timeout_time)
               timed_out++;
 
-	    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);
-	}
+            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);
+        }
     }
   else
     {
@@ -568,38 +571,36 @@ nat44_show_summary_command_fn (vlib_main_t * vm, unformat_input_t * input,
         if (now >= sess_timeout_time)
           timed_out++;
 
-	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;
-	  }
+        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);
@@ -616,7 +617,6 @@ 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;
 }
 
@@ -636,6 +636,10 @@ 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)
@@ -646,6 +650,10 @@ 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;
 }
@@ -829,13 +837,14 @@ 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;
-  int is_add = 1, rv;
-  u32 flags = 0;
-  u32 sw_if_index = ~0;
-  ip_protocol_t proto = 0;
+  u32 sw_if_index, flags = 0;
+  int is_add = 1;
 
   if (!unformat_user (input, unformat_line_input, line_input))
     return clib_error_return (0, NAT44_ED_EXPECTED_ARGUMENT);
@@ -877,7 +886,7 @@ 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_ip_protocol, &proto))
+      else if (unformat (line_input, "%U", unformat_nat_protocol, &proto))
 	;
       else if (unformat (line_input, "self-twice-nat"))
 	{
@@ -974,7 +983,7 @@ 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;
-  ip_protocol_t proto;
+  nat_protocol_t proto;
   ip4_address_t addr;
 
   flags = NAT_SM_FLAG_IDENTITY_NAT;
@@ -994,7 +1003,7 @@ 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_ip_protocol, &proto,
+      else if (unformat (line_input, "%U %u", unformat_nat_protocol, &proto,
 			 &port))
 	{
 	  port_set = 1;
@@ -1071,7 +1080,7 @@ 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;
-  ip_protocol_t proto;
+  nat_protocol_t proto;
   nat44_lb_addr_port_t *locals = 0, local;
   int rv, is_add = 1;
   u32 flags = 0;
@@ -1105,7 +1114,7 @@ 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_ip_protocol,
+      else if (unformat (line_input, "protocol %U", unformat_nat_protocol,
 			 &proto))
 	{
 	  proto_set = 1;
@@ -1193,7 +1202,7 @@ 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;
-  ip_protocol_t proto;
+  nat_protocol_t proto;
   u8 proto_set = 0;
 
   /* Get a line of input. */
@@ -1212,7 +1221,7 @@ 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_ip_protocol,
+      else if (unformat (line_input, "protocol %U", unformat_nat_protocol,
 			 &proto))
 	proto_set = 1;
       else if (unformat (line_input, "del"))
@@ -1538,7 +1547,7 @@ 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;
-  ip_protocol_t proto;
+  nat_protocol_t proto;
   int is_in = 0;
   int rv;
 
@@ -1547,8 +1556,9 @@ 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_ip_protocol, &proto))
+      if (unformat
+	  (line_input, "%U:%u %U", unformat_ip4_address, &addr, &port,
+	   unformat_nat_protocol, &proto))
 	;
       else if (unformat (line_input, "in"))
 	{
@@ -1574,8 +1584,8 @@ 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), proto, vrf_id,
-			     is_in);
+			     clib_host_to_net_u16 (eh_port),
+			     nat_proto_to_ip_proto (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 5eb683d888e..442f6ad3d7a 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_format.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_format.c
@@ -20,6 +20,39 @@
 #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)
 {
@@ -40,6 +73,25 @@ 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);
@@ -64,7 +116,7 @@ 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 (nat44_ed_is_unk_proto (sess->proto))
+  if (snat_is_unk_proto_session (sess))
     {
       s = format (s, "  i2o %U proto %u fib %u\n",
 		  format_ip4_address, &sess->in2out.addr,
@@ -75,13 +127,14 @@ 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_ip_protocol, sess->proto,
+      s = format (s, "  i2o %U proto %U port %d fib %d\n",
+		  format_ip4_address, &sess->in2out.addr,
+		  format_nat_protocol, sess->nat_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_ip_protocol,
-		  sess->proto, clib_net_to_host_u16 (sess->out2in.port),
+		  format_ip4_address, &sess->out2in.addr, format_nat_protocol,
+		  sess->nat_proto, clib_net_to_host_u16 (sess->out2in.port),
 		  sess->out2in.fib_index);
     }
   if (nat44_ed_is_twice_nat_session (sess))
@@ -130,8 +183,9 @@ 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_ip_protocol,
-		    m->proto, format_ip4_address, &m->local_addr,
+	s = format (s, "identity mapping %U %U:%d",
+		    format_nat_protocol, m->proto,
+		    format_ip4_address, &m->local_addr,
 		    clib_net_to_host_u16 (m->local_port));
 
       pool_foreach (local, m->locals)
@@ -155,8 +209,8 @@ 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_ip_protocol, m->proto,
-		    format_ip4_address, &m->external_addr,
+	    format (s, "%U external %U:%d %s %s", format_nat_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" :
@@ -173,7 +227,7 @@ 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_ip_protocol, m->proto, format_ip4_address,
+		    format_nat_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,
@@ -196,11 +250,12 @@ 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_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);
+    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);
 
   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 73dacce57e6..0e330e17b36 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_in2out.c
@@ -25,12 +25,18 @@
 #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
@@ -160,7 +166,7 @@ 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, u8 proto, u32 thread_index, snat_address_t *a,
+  snat_main_t *sm, u32 nat_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)
 {
@@ -181,13 +187,27 @@ nat_ed_alloc_addr_and_port_with_snat_address (
   u16 attempts = ED_PORT_ALLOC_ATTEMPTS;
   do
     {
-      if (IP_PROTOCOL_ICMP == proto)
+      if (NAT_PROTOCOL_ICMP == nat_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;
@@ -203,8 +223,9 @@ 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,
-			    u32 snat_thread_index, snat_session_t *s,
-			    ip4_address_t *outside_addr, u16 *outside_port)
+			    u16 port_per_thread, u32 snat_thread_index,
+			    snat_session_t *s, ip4_address_t *outside_addr,
+			    u16 *outside_port)
 {
   int i;
   snat_address_t *a, *ga = 0;
@@ -219,7 +240,7 @@ 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, sm->port_per_thread,
+		sm, nat_proto, thread_index, a, port_per_thread,
 		snat_thread_index, s, outside_addr, outside_port);
 	    }
 	  else if (a->fib_index == ~0)
@@ -234,7 +255,7 @@ 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, sm->port_per_thread,
+		sm, nat_proto, thread_index, a, port_per_thread,
 		snat_thread_index, s, outside_addr, outside_port);
 	    }
 	  else if (a->fib_index == ~0)
@@ -246,8 +267,8 @@ 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, sm->port_per_thread,
-	    snat_thread_index, s, outside_addr, outside_port);
+	    sm, nat_proto, thread_index, a, port_per_thread, snat_thread_index,
+	    s, outside_addr, outside_port);
 	}
     }
   /* Totally out of translations to use... */
@@ -283,18 +304,23 @@ 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, ip_protocol_t match_protocol,
-			     ip4_address_t *daddr, u16 *dport)
+			     u16 match_port, nat_protocol_t match_protocol,
+			     u32 match_fib_index, ip4_address_t *daddr,
+			     u16 *dport)
 {
-  snat_static_mapping_t *m =
-    nat44_ed_sm_o2i_lookup (sm, match_addr, match_port, 0, match_protocol);
-  if (!m)
+  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))
     {
       /* Try address only mapping */
-      m = nat44_ed_sm_o2i_lookup (sm, match_addr, 0, 0, 0);
-      if (!m)
+      init_nat_k (&kv, match_addr, 0, 0, 0);
+      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
+				  &value))
 	return 0;
     }
+
+  snat_static_mapping_t *m =
+    pool_elt_at_index (sm->static_mappings, value.value);
   *daddr = m->local_addr;
   if (dport)
     {
@@ -317,6 +343,7 @@ 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;
@@ -355,9 +382,9 @@ 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, 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,
+				 nat_proto, &sm_addr, &sm_port, &sm_fib_index,
+				 0, 0, 0, &lb, 0, &is_identity_nat, 0))
     {
       is_sm = 0;
     }
@@ -371,7 +398,7 @@ slow_path_ed (vlib_main_t *vm, snat_main_t *sm, vlib_buffer_t *b,
       is_sm = 1;
     }
 
-  if (PREDICT_TRUE (proto == IP_PROTOCOL_TCP))
+  if (PREDICT_TRUE (nat_proto == NAT_PROTOCOL_TCP))
     {
       if (PREDICT_FALSE (!tcp_flags_is_init (
 	    vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags)))
@@ -388,7 +415,7 @@ 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->proto = proto;
+      s->nat_proto = nat_proto;
       s->in2out.fib_index = rx_fib_index;
       s->out2in.fib_index = outside_fib_index;
 
@@ -396,8 +423,8 @@ 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,
-							proto, &daddr, &dport);
+      int is_hairpinning = nat44_ed_external_sm_lookup (
+	sm, r_addr, r_port, nat_proto, outside_fib_index, &daddr, &dport);
       s->flags |= is_hairpinning * SNAT_SESSION_FLAG_HAIRPINNING;
 
       // destination addr/port updated with real values in
@@ -405,7 +432,7 @@ 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 (IP_PROTOCOL_ICMP == proto)
+      if (NAT_PROTOCOL_ICMP == nat_proto)
 	{
 	  nat_6t_flow_icmp_id_rewrite_set (&s->o2i, l_port);
 	}
@@ -415,9 +442,10 @@ 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, proto, thread_index,
-				      l_addr, tsm->snat_thread_index, s,
-				      &outside_addr, &outside_port))
+      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))
 	{
 	  nat_elog_notice (sm, "addresses exhausted");
 	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
@@ -434,17 +462,17 @@ 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->proto = proto;
+      s->nat_proto = nat_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,
-							proto, &daddr, &dport);
+      int is_hairpinning = nat44_ed_external_sm_lookup (
+	sm, r_addr, r_port, nat_proto, outside_fib_index, &daddr, &dport);
       s->flags |= is_hairpinning * SNAT_SESSION_FLAG_HAIRPINNING;
 
-      if (IP_PROTOCOL_ICMP == proto)
+      if (NAT_PROTOCOL_ICMP == nat_proto)
 	{
 	  nat_6t_o2i_flow_init (sm, thread_index, s, daddr, sm_port, sm_addr,
 				sm_port, s->out2in.fib_index, proto);
@@ -475,7 +503,7 @@ 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 (IP_PROTOCOL_ICMP == proto)
+  if (NAT_PROTOCOL_ICMP == nat_proto)
     {
       nat_6t_flow_icmp_id_rewrite_set (&s->i2o, outside_port);
     }
@@ -493,14 +521,17 @@ 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->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->nat_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->proto, 0);
+			 &s->ext_host_addr, s->ext_host_port, s->nat_proto, 0);
 
   per_vrf_sessions_register_session (s, thread_index);
 
@@ -509,6 +540,12 @@ 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;
@@ -523,10 +560,9 @@ 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.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);
+  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);
 
   /* NAT packet aimed at external address if has active sessions */
   if (clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
@@ -571,18 +607,18 @@ 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.as_u32, lookup_sport, lookup_daddr.as_u32,
-		 lookup_dport, 0, lookup_protocol);
+      init_ed_k (&kv, lookup_saddr, lookup_sport, lookup_daddr, lookup_dport,
+		 0, lookup_protocol);
     }
   else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
     {
-      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);
+      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);
     }
   else
     {
-      init_ed_k (&kv, ip->src_address.as_u32, 0, ip->dst_address.as_u32, 0, 0,
+      init_ed_k (&kv, ip->src_address, 0, ip->dst_address, 0, 0,
 		 ip->protocol);
     }
 
@@ -629,8 +665,8 @@ 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.as_u32, src_port, ip->dst_address.as_u32,
-	     dst_port, tx_fib_index, ip->protocol);
+  init_ed_k (&kv, ip->src_address, src_port, ip->dst_address, 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));
@@ -640,7 +676,7 @@ 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))
 	{
-	  nat44_ed_free_session_data (sm, s, thread_index, 0);
+	  nat_free_session_data (sm, s, thread_index, 0);
 	  nat_ed_session_delete (sm, s, thread_index, 1);
 	}
       return 1;
@@ -667,8 +703,8 @@ nat44_ed_not_translate_output_feature (snat_main_t *sm, vlib_buffer_t *b,
       s = NULL;
     }
 
-  init_ed_k (&kv, ip->dst_address.as_u32, dst_port, ip->src_address.as_u32,
-	     src_port, rx_fib_index, ip->protocol);
+  init_ed_k (&kv, ip->dst_address, dst_port, ip->src_address, 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));
@@ -728,8 +764,9 @@ 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, IP_PROTOCOL_ICMP, rx_fib_index)))
+      if (PREDICT_FALSE (nat44_ed_not_translate (vm, sm, node, sw_if_index, b,
+						 ip, NAT_PROTOCOL_ICMP,
+						 rx_fib_index)))
 	{
 	  return next;
 	}
@@ -782,6 +819,7 @@ 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];
@@ -814,11 +852,12 @@ 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 */
-  m = nat44_ed_sm_i2o_lookup (sm, ip->src_address, 0, rx_fib_index,
-			      ip->protocol);
-  if (m)
+  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
     {
+      m = pool_elt_at_index (sm->static_mappings, value.value);
       new_src_addr = m->external_addr;
     }
   else
@@ -827,9 +866,8 @@ 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.as_u32, 0,
-			 ip->dst_address.as_u32, 0, outside_fib_index,
-			 ip->protocol);
+	      init_ed_k (&s_kv, s->out2in.addr, 0, ip->dst_address, 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;
@@ -842,9 +880,8 @@ 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.as_u32, 0,
-			 ip->dst_address.as_u32, 0, outside_fib_index,
-			 ip->protocol);
+	      init_ed_k (&s_kv, sm->addresses[i].addr, 0, ip->dst_address, 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;
@@ -873,8 +910,9 @@ 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, ip->protocol, &new_dst_addr, NULL);
+  int is_hairpinning =
+    nat44_ed_external_sm_lookup (sm, ip->dst_address, 0, NAT_PROTOCOL_OTHER,
+				 outside_fib_index, &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);
@@ -887,6 +925,7 @@ 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;
@@ -948,7 +987,7 @@ 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;
-      ip_protocol_t proto0;
+      nat_protocol_t proto0;
       ip4_header_t *ip0;
       snat_session_t *s0 = 0;
       clib_bihash_kv_16_8_t kv0, value0;
@@ -1000,7 +1039,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	  goto trace0;
 	}
 
-      proto0 = ip0->protocol;
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
       if (is_output_feature)
 	{
@@ -1010,7 +1049,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	    goto trace0;
 	}
 
-      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	{
 	  if (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 		ICMP4_echo_request &&
@@ -1064,8 +1103,8 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 	  s0 = NULL;
 	}
 
-      init_ed_k (&kv0, lookup.saddr.as_u32, lookup.sport, lookup.daddr.as_u32,
-		 lookup.dport, lookup.fib_index, lookup.proto);
+      init_ed_k (&kv0, lookup.saddr, lookup.sport, lookup.daddr, lookup.dport,
+		 lookup.fib_index, lookup.proto);
 
       // lookup flow
       if (clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
@@ -1087,7 +1126,7 @@ 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
-	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	  nat_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;
@@ -1115,7 +1154,7 @@ 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)
 	{
-	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	  nat_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;
@@ -1136,7 +1175,7 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
       else
 	{
 	  translation_error = NAT_ED_TRNSL_ERR_FLOW_MISMATCH;
-	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	  nat_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];
@@ -1147,7 +1186,7 @@ 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)))
 	{
-	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	  nat_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];
@@ -1156,20 +1195,20 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t *vm,
 
       switch (proto0)
 	{
-	case IP_PROTOCOL_TCP:
+	case NAT_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 IP_PROTOCOL_UDP:
+	case NAT_PROTOCOL_UDP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.in2out.udp,
 					 thread_index, cntr_sw_if_index0, 1);
 	  break;
-	case IP_PROTOCOL_ICMP:
+	case NAT_PROTOCOL_ICMP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.in2out.icmp,
 					 thread_index, cntr_sw_if_index0, 1);
 	  break;
-	default:
+	case NAT_PROTOCOL_OTHER:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.in2out.other,
 					 thread_index, cntr_sw_if_index0, 1);
 	  break;
@@ -1250,7 +1289,7 @@ 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;
-      ip_protocol_t proto0;
+      nat_protocol_t proto0;
       ip4_header_t *ip0;
       udp_header_t *udp0;
       icmp46_header_t *icmp0;
@@ -1287,9 +1326,9 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 
       udp0 = ip4_next_header (ip0);
       icmp0 = (icmp46_header_t *) udp0;
-      proto0 = ip0->protocol;
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-      if (PREDICT_FALSE (nat44_ed_is_unk_proto (proto0)))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	{
 	  s0 = nat44_ed_in2out_slowpath_unknown_proto (
 	    sm, b0, ip0, rx_fib_index0, thread_index, now, vm, node);
@@ -1301,7 +1340,7 @@ 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)))
 	    {
-	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	      nat_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];
@@ -1313,7 +1352,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 	  goto trace0;
 	}
 
-      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	{
 	  next[0] = icmp_in2out_ed_slow_path (
 	    sm, b0, ip0, icmp0, rx_sw_if_index0, rx_fib_index0, node, next[0],
@@ -1323,7 +1362,7 @@ 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)))
 	    {
-	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	      nat_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];
@@ -1335,10 +1374,10 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 	  goto trace0;
 	}
 
-      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);
+      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);
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
 	{
 	  ASSERT (thread_index == ed_value_get_thread_index (&value0));
@@ -1348,7 +1387,7 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t *vm,
 
 	  if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
 	    {
-	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	      nat_free_session_data (sm, s0, thread_index, 0);
 	      nat_ed_session_delete (sm, s0, thread_index, 1);
 	      s0 = NULL;
 	    }
@@ -1368,11 +1407,11 @@ 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 == 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))
+	      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))
 		goto trace0;
 	    }
 	  else
@@ -1403,14 +1442,14 @@ 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)))
 	{
-	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	  nat_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 == IP_PROTOCOL_TCP))
+      if (PREDICT_TRUE (proto0 == NAT_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 cb418960249..0d75e736849 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_inlines.h
+++ b/src/plugins/nat/nat44-ed/nat44_ed_inlines.h
@@ -26,50 +26,114 @@
 #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
-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)
+split_nat_key (u64 key, ip4_address_t *addr, u16 *port, u32 *fib_index,
+	       nat_protocol_t *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;
+  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_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 (clib_bihash_kv_8_8_t *kv, ip4_address_t addr, u16 port,
+	    u32 fib_index, nat_protocol_t proto)
 {
-  init_ed_k (kv, l_addr, l_port, r_addr, r_port, fib_index, 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_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);
+}
+
+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_nat_k (kv, s->in2out.addr, s->in2out.port, s->in2out.fib_index,
+	      s->nat_proto);
   kv->value = (u64) thread_index << 32 | session_index;
 }
 
 always_inline void
-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)
+init_nat_o2i_k (clib_bihash_kv_8_8_t *kv, snat_session_t *s)
 {
-  return init_ed_kv (kv, addr, port, 0, 0, fib_index, proto, 0, sm_index);
+  return init_nat_k (kv, s->out2in.addr, s->out2in.port, s->out2in.fib_index,
+		     s->nat_proto);
 }
 
 always_inline void
-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)
+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)
 {
-  return init_ed_kv (kv, 0, 0, e_addr, e_port, fib_index, proto, 0, sm_index);
+  return value->value & ~(u32) 0;
 }
 
 always_inline void
-nat44_ed_sm_init_i2o_k (clib_bihash_kv_16_8_t *kv, u32 addr, u16 port,
-			u32 fib_index, u8 proto)
+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)
 {
-  return nat44_ed_sm_init_i2o_kv (kv, addr, port, fib_index, proto, 0);
+  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;
 }
 
 always_inline void
-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_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)
 {
-  return nat44_ed_sm_init_o2i_kv (kv, e_addr, e_port, fib_index, proto, 0);
+  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 u32
@@ -151,16 +215,16 @@ 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 (inner_ip0->protocol)
+      switch (ip_proto_to_nat_proto (inner_ip0->protocol))
 	{
-	case IP_PROTOCOL_ICMP:
+	case NAT_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 IP_PROTOCOL_UDP:
-	case IP_PROTOCOL_TCP:
+	case NAT_PROTOCOL_UDP:
+	case NAT_PROTOCOL_TCP:
 	  *lookup_sport = ((tcp_udp_header_t *) l4_header)->dst_port;
 	  *lookup_dport = ((tcp_udp_header_t *) l4_header)->src_port;
 	  break;
@@ -174,15 +238,13 @@ 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->proto)
+  switch (s->nat_proto)
     {
-    case IP_PROTOCOL_ICMP:
-      /* fallthrough */
-    case IP_PROTOCOL_ICMP6:
+    case NAT_PROTOCOL_ICMP:
       return sm->timeouts.icmp;
-    case IP_PROTOCOL_UDP:
+    case NAT_PROTOCOL_UDP:
       return sm->timeouts.udp;
-    case IP_PROTOCOL_TCP:
+    case NAT_PROTOCOL_TCP:
       {
 	if (s->state)
 	  return sm->timeouts.tcp.transitory;
@@ -238,7 +300,7 @@ 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.as_u32, f->match.sport, f->match.daddr.as_u32,
+  init_ed_k (kv, f->match.saddr, f->match.sport, f->match.daddr,
 	     f->match.dport, f->match.fib_index, f->match.proto);
 }
 
@@ -246,7 +308,7 @@ 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.as_u32, f->match.sport, f->match.daddr.as_u32,
+  init_ed_kv (kv, f->match.saddr, f->match.sport, f->match.daddr,
 	      f->match.dport, f->match.fib_index, f->match.proto, thread_idx,
 	      session_idx);
 }
@@ -286,15 +348,6 @@ 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);
@@ -343,7 +396,7 @@ 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))
 	{
-	  nat44_ed_free_session_data (sm, s, thread_index, 0);
+	  nat_free_session_data (sm, s, thread_index, 0);
 	  nat_ed_session_delete (sm, s, thread_index, 0);
 	  return 1;
 	}
@@ -815,19 +868,6 @@ 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 5ad57a17098..cb21b0f62c5 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_out2in.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_out2in.c
@@ -25,6 +25,7 @@
 #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>
@@ -126,8 +127,8 @@ 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.as_u32, src_port, ip->dst_address.as_u32,
-	     dst_port, rx_fib_index, ip->protocol);
+  init_ed_k (&kv, ip->src_address, src_port, ip->dst_address, dst_port,
+	     rx_fib_index, ip->protocol);
   if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     return 1;
 
@@ -141,8 +142,8 @@ 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,
-  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,
+  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,
   snat_static_mapping_t *mapping);
 
 static inline u32
@@ -179,10 +180,10 @@ 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->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_proto_to_nat_proto (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)
@@ -228,8 +229,8 @@ 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, lookup_protocol, node, thread_index, 0, 0,
-    vlib_time_now (vm), m);
+    rx_fib_index, ip_proto_to_nat_proto (lookup_protocol), node, rx_fib_index,
+    thread_index, 0, 0, vlib_time_now (vm), m);
   if (!s)
     next = NAT_NEXT_DROP;
 
@@ -264,29 +265,44 @@ out:
   return next;
 }
 
+// allocate exact address based on preference
 static_always_inline int
-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)
+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)
 {
+  snat_main_t *sm = &snat_main;
   u32 portnum;
 
-  for (int i = 0; i < ED_PORT_ALLOC_ATTEMPTS; ++i)
+  switch (proto)
     {
-      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;
-	}
+#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;
     }
 
   /* Totally out of translations to use... */
@@ -295,56 +311,80 @@ nat44_ed_alloc_i2o_port (snat_main_t *sm, snat_address_t *a, snat_session_t *s,
 }
 
 static_always_inline int
-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)
+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)
 {
+  snat_main_t *sm = &snat_main;
   snat_address_t *a, *ga = 0;
+  u32 portnum;
   int i;
 
-  if (vec_len (addresses) > 0)
+  for (i = 0; i < vec_len (addresses); i++)
     {
-      int s_addr_offset = i2o_addr.as_u32 % vec_len (addresses);
-
-      for (i = s_addr_offset; i < vec_len (addresses); ++i)
+      a = addresses + i;
+      switch (proto)
 	{
-	  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;
-	    }
-	}
-
-      for (i = 0; i < s_addr_offset; ++i)
-	{
-	  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;
-	    }
+#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;
 	}
+    }
 
-      if (ga)
+  if (ga)
+    {
+      a = ga;
+      switch (proto)
 	{
-	  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);
+#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;
 	}
     }
 
@@ -357,23 +397,23 @@ 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,
-  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,
+  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,
   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, o2i_fib_index, thread_index)))
+  if (PREDICT_FALSE
+      (nat44_ed_maximum_sessions_exceeded (sm, rx_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, proto);
+  s = nat_ed_session_alloc (sm, thread_index, now, nat_proto);
   if (!s)
     {
       b->error = node->errors[NAT_OUT2IN_ED_ERROR_MAX_SESSIONS_EXCEEDED];
@@ -385,7 +425,7 @@ create_session_for_static_mapping_ed (
 
   s->ext_host_addr.as_u32 = ip->src_address.as_u32;
   s->ext_host_port =
-    proto == IP_PROTOCOL_ICMP ? 0 : vnet_buffer (b)->ip.reass.l4_src_port;
+    nat_proto == NAT_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;
@@ -397,9 +437,9 @@ create_session_for_static_mapping_ed (
   s->in2out.addr = i2o_addr;
   s->in2out.port = i2o_port;
   s->in2out.fib_index = i2o_fib_index;
-  s->proto = proto;
+  s->nat_proto = nat_proto;
 
-  if (IP_PROTOCOL_ICMP == proto)
+  if (NAT_PROTOCOL_ICMP == nat_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);
@@ -445,23 +485,33 @@ create_session_for_static_mapping_ed (
 
       if (filter)
 	{
-	  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);
+	  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);
 	  s->flags |= SNAT_SESSION_FLAG_EXACT_ADDRESS;
 	}
       else
 	{
-	  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);
+	  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);
 	}
 
       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;
 	}
@@ -469,7 +519,7 @@ 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 (IP_PROTOCOL_ICMP == proto)
+      if (NAT_PROTOCOL_ICMP == nat_proto)
 	{
 	  nat_6t_flow_icmp_id_rewrite_set (&s->o2i, s->ext_host_nat_port);
 	}
@@ -480,8 +530,11 @@ 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 (IP_PROTOCOL_ICMP == proto)
+      if (NAT_PROTOCOL_ICMP == nat_proto)
 	{
 	  nat_6t_flow_icmp_id_rewrite_set (&s->i2o, s->ext_host_port);
 	}
@@ -489,21 +542,10 @@ 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 (IP_PROTOCOL_ICMP == proto)
+      if (NAT_PROTOCOL_ICMP == nat_proto)
 	{
 	  nat_6t_i2o_flow_init (sm, thread_index, s, i2o_addr, i2o_port,
 				s->ext_host_addr, i2o_port, i2o_fib_index,
@@ -515,9 +557,10 @@ 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 (IP_PROTOCOL_ICMP == proto)
+  if (NAT_PROTOCOL_ICMP == nat_proto)
     {
       nat_6t_flow_icmp_id_rewrite_set (&s->i2o, o2i_port);
     }
@@ -536,15 +579,18 @@ 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->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->nat_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->proto,
+			 &s->ext_host_addr, s->ext_host_port, s->nat_proto,
 			 nat44_ed_is_twice_nat_session (s));
 
   per_vrf_sessions_register_session (s, thread_index);
@@ -588,8 +634,8 @@ 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.as_u32, lookup_sport, lookup_daddr.as_u32,
-	     lookup_dport, rx_fib_index, lookup_protocol);
+  init_ed_k (&kv, lookup_saddr, lookup_sport, lookup_daddr, lookup_dport,
+	     rx_fib_index, lookup_protocol);
 
   if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv, &value))
     {
@@ -606,6 +652,8 @@ 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)))
@@ -618,12 +666,19 @@ 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->proto = ip->protocol;
+      s->nat_proto = proto;
+      if (proto == NAT_PROTOCOL_OTHER)
+	{
+	  s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
+	  s->out2in.port = ip->protocol;
+	}
       s->out2in.fib_index = rx_fib_index;
       s->in2out.addr = s->out2in.addr;
       s->in2out.port = s->out2in.port;
@@ -664,6 +719,7 @@ 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;
 
@@ -675,13 +731,15 @@ nat44_ed_out2in_slowpath_unknown_proto (snat_main_t *sm, vlib_buffer_t *b,
       return 0;
     }
 
-  m = nat44_ed_sm_o2i_lookup (sm, ip->dst_address, 0, 0, ip->protocol);
-  if (!m)
+  init_nat_k (&kv, ip->dst_address, 0, 0, 0);
+  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
     {
       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)
@@ -692,6 +750,7 @@ 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;
@@ -754,7 +813,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
     {
       vlib_buffer_t *b0;
       u32 sw_if_index0, rx_fib_index0;
-      ip_protocol_t proto0;
+      nat_protocol_t proto0;
       ip4_header_t *ip0;
       snat_session_t *s0 = 0;
       clib_bihash_kv_16_8_t kv0, value0;
@@ -803,9 +862,9 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      proto0 = ip0->protocol;
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	{
 	  if (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 		ICMP4_echo_request &&
@@ -854,8 +913,8 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 	  s0 = NULL;
 	}
 
-      init_ed_k (&kv0, lookup.saddr.as_u32, lookup.sport, lookup.daddr.as_u32,
-		 lookup.dport, lookup.fib_index, lookup.proto);
+      init_ed_k (&kv0, lookup.saddr, lookup.sport, lookup.daddr, lookup.dport,
+		 lookup.fib_index, lookup.proto);
 
       // lookup flow
       if (clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
@@ -876,7 +935,7 @@ 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
-	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	  nat_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;
@@ -907,7 +966,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
       if (now >= sess_timeout_time)
 	{
 	  // session is closed, go slow path
-	  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	  nat_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;
@@ -930,7 +989,7 @@ 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 == IP_PROTOCOL_UDP &&
+		proto0 == NAT_PROTOCOL_UDP &&
 		(vnet_buffer (b0)->ip.reass.l4_dst_port ==
 		 clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
 	    {
@@ -955,7 +1014,7 @@ 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;
-		  nat44_ed_free_session_data (sm, s0, thread_index, 0);
+		  nat_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];
@@ -975,7 +1034,7 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 
       switch (proto0)
 	{
-	case IP_PROTOCOL_TCP:
+	case NAT_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,
@@ -987,15 +1046,15 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
 					   reass.tcp_seq_number,
 					   thread_index);
 	  break;
-	case IP_PROTOCOL_UDP:
+	case NAT_PROTOCOL_UDP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.udp,
 					 thread_index, sw_if_index0, 1);
 	  break;
-	case IP_PROTOCOL_ICMP:
+	case NAT_PROTOCOL_ICMP:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.icmp,
 					 thread_index, sw_if_index0, 1);
 	  break;
-	default:
+	case NAT_PROTOCOL_OTHER:
 	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.other,
 					 thread_index, sw_if_index0, 1);
 	  break;
@@ -1073,7 +1132,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
     {
       vlib_buffer_t *b0;
       u32 sw_if_index0, rx_fib_index0;
-      ip_protocol_t proto0;
+      nat_protocol_t proto0;
       ip4_header_t *ip0;
       udp_header_t *udp0;
       icmp46_header_t *icmp0;
@@ -1109,9 +1168,9 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 
       udp0 = ip4_next_header (ip0);
       icmp0 = (icmp46_header_t *) udp0;
-      proto0 = ip0->protocol;
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-      if (PREDICT_FALSE (nat44_ed_is_unk_proto (proto0)))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	{
 	  s0 = nat44_ed_out2in_slowpath_unknown_proto (
 	    sm, b0, ip0, rx_fib_index0, thread_index, now, vm, node);
@@ -1136,7 +1195,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      if (PREDICT_FALSE (proto0 == IP_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	{
 	  next[0] = icmp_out2in_ed_slow_path
 	    (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
@@ -1158,10 +1217,10 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      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);
+      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);
 
       s0 = NULL;
       if (!clib_bihash_search_16_8 (&sm->flow_hash, &kv0, &value0))
@@ -1173,7 +1232,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 
 	  if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
 	    {
-	      nat44_ed_free_session_data (sm, s0, thread_index, 0);
+	      nat_free_session_data (sm, s0, thread_index, 0);
 	      nat_ed_session_delete (sm, s0, thread_index, 1);
 	      s0 = NULL;
 	    }
@@ -1194,10 +1253,10 @@ 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 == IP_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 == NAT_PROTOCOL_UDP
+				 && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
+				     clib_host_to_net_u16
+				     (UDP_DST_PORT_dhcp_to_client))))
 		{
 		  goto trace0;
 		}
@@ -1228,9 +1287,9 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  if (PREDICT_FALSE (identity_nat0))
 	    goto trace0;
 
-	  if ((proto0 == IP_PROTOCOL_TCP) &&
-	      !tcp_flags_is_init (
-		vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
+	  if ((proto0 == NAT_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;
@@ -1238,10 +1297,16 @@ 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, 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, rx_fib_index0,
+						     thread_index, twice_nat0,
+						     lb_nat0, now, m);
 	  if (!s0)
 	    {
 	      next[0] = NAT_NEXT_DROP;
@@ -1257,7 +1322,7 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
 	  goto trace0;
 	}
 
-      if (PREDICT_TRUE (proto0 == IP_PROTOCOL_TCP))
+      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 	{
 	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
 					 thread_index, sw_if_index0, 1);