session: support multiple worker binds

Allows app workers to listen on the same session endpoint. Incoming
connects are spread across the workers in a round-robin fashion

Change-Id: Ib5f5817230d9abc6127a85cdbdcad70d980c0f7f
Signed-off-by: Florin Coras <fcoras@cisco.com>

18 files changed, 660 insertions, 366 deletions

diff --git a/src/vcl/vcl_bapi.c b/src/vcl/vcl_bapi.c
index 44e6d9d1d04..0c46d8220fd 100644
--- a/src/vcl/vcl_bapi.c
+++ b/src/vcl/vcl_bapi.c
@@ -138,9 +138,9 @@ static void
 vl_api_app_worker_add_del_reply_t_handler (vl_api_app_worker_add_del_reply_t *
 					   mp)
 {
+  int n_fds = 0, *fds = 0;
   vcl_worker_t *wrk;
-  int n_fds = 0;
-  int *fds = 0;
+  u32 wrk_index;
 
   if (mp->retval)
     {
@@ -148,14 +148,14 @@ vl_api_app_worker_add_del_reply_t_handler (vl_api_app_worker_add_del_reply_t *
 		    format_api_error, ntohl (mp->retval));
       goto failed;
     }
-  ASSERT (mp->context == mp->wrk_index);
-  if (mp->context != mp->wrk_index)
+  wrk_index = clib_net_to_host_u32 (mp->wrk_index);
+  if (mp->context != wrk_index)
     {
       clib_warning ("VCL<%d>: wrk numbering doesn't match ours: %u, vpp: %u",
-		    getpid (), mp->context, mp->wrk_index);
+		    getpid (), mp->context, wrk_index);
       goto failed;
     }
-  wrk = vcl_worker_get (mp->context);
+  wrk = vcl_worker_get (wrk_index);
   wrk->app_event_queue = uword_to_pointer (mp->app_event_queue_address,
 					   svm_msg_q_t *);
 
@@ -301,10 +301,31 @@ vl_api_unbind_sock_reply_t_handler (vl_api_unbind_sock_reply_t * mp)
     VDBG (1, "VCL<%d>: sid %u: unbind succeeded!", getpid (), mp->context);
 }
 
+static void
+vl_api_disconnect_session_reply_t_handler (vl_api_disconnect_session_reply_t *
+					   mp)
+{
+  if (mp->retval)
+    clib_warning ("VCL<%d>: ERROR: sid %u: disconnect failed: %U",
+		  getpid (), mp->context, format_api_error,
+		  ntohl (mp->retval));
+}
+
+static void
+vl_api_connect_sock_reply_t_handler (vl_api_connect_sock_reply_t * mp)
+{
+  if (mp->retval)
+    clib_warning ("VCL<%d>: ERROR: sid %u: connect failed: %U",
+		  getpid (), mp->context, format_api_error,
+		  ntohl (mp->retval));
+}
+
 #define foreach_sock_msg                                        	\
 _(SESSION_ENABLE_DISABLE_REPLY, session_enable_disable_reply)   	\
 _(BIND_SOCK_REPLY, bind_sock_reply)                             	\
 _(UNBIND_SOCK_REPLY, unbind_sock_reply)                         	\
+_(CONNECT_SOCK_REPLY, connect_sock_reply)                         	\
+_(DISCONNECT_SESSION_REPLY, disconnect_session_reply)			\
 _(APPLICATION_ATTACH_REPLY, application_attach_reply)           	\
 _(APPLICATION_DETACH_REPLY, application_detach_reply)           	\
 _(MAP_ANOTHER_SEGMENT, map_another_segment)                     	\
@@ -421,13 +442,12 @@ vppcom_send_connect_sock (vcl_session_t * session)
 {
   vl_api_connect_sock_t *cmp;
 
-  /* Assumes caller as acquired the spinlock: vcm->sessions_lockp */
   cmp = vl_msg_api_alloc (sizeof (*cmp));
   memset (cmp, 0, sizeof (*cmp));
   cmp->_vl_msg_id = ntohs (VL_API_CONNECT_SOCK);
   cmp->client_index = vcm->my_client_index;
   cmp->context = session->session_index;
-
+  cmp->wrk_index = vcl_get_worker_index ();
   cmp->is_ip4 = session->transport.is_ip4;
   clib_memcpy (cmp->ip, &session->transport.rmt_ip, sizeof (cmp->ip));
   cmp->port = session->transport.rmt_port;
@@ -437,13 +457,10 @@ vppcom_send_connect_sock (vcl_session_t * session)
 }
 
 void
-vppcom_send_disconnect_session (u64 vpp_handle, u32 session_index)
+vppcom_send_disconnect_session (u64 vpp_handle)
 {
   vl_api_disconnect_session_t *dmp;
 
-  VDBG (1, "VCL<%d>: vpp handle 0x%llx, sid %u: sending disconnect msg",
-	getpid (), vpp_handle, session_index);
-
   dmp = vl_msg_api_alloc (sizeof (*dmp));
   memset (dmp, 0, sizeof (*dmp));
   dmp->_vl_msg_id = ntohs (VL_API_DISCONNECT_SESSION);
@@ -467,6 +484,7 @@ vppcom_send_bind_sock (vcl_session_t * session)
   bmp->_vl_msg_id = ntohs (VL_API_BIND_SOCK);
   bmp->client_index = vcm->my_client_index;
   bmp->context = session->session_index;
+  bmp->wrk_index = vcl_get_worker_index ();
   bmp->is_ip4 = session->transport.is_ip4;
   clib_memcpy (bmp->ip, &session->transport.lcl_ip, sizeof (bmp->ip));
   bmp->port = session->transport.lcl_port;
@@ -485,6 +503,7 @@ vppcom_send_unbind_sock (u64 vpp_handle)
 
   ump->_vl_msg_id = ntohs (VL_API_UNBIND_SOCK);
   ump->client_index = vcm->my_client_index;
+  ump->wrk_index = vcl_get_worker_index ();
   ump->handle = vpp_handle;
   vl_msg_api_send_shmem (vcm->vl_input_queue, (u8 *) & ump);
 }
diff --git a/src/vcl/vcl_debug.h b/src/vcl/vcl_debug.h
index 13e6726c259..3faa45822f8 100644
--- a/src/vcl/vcl_debug.h
+++ b/src/vcl/vcl_debug.h
@@ -22,7 +22,7 @@
 
 #define VDBG(_lvl, _fmt, _args...) 					\
   if (vcm->debug > _lvl)						\
-    clib_warning (_fmt, ##_args)
+    clib_warning ("vcl<w%u>: " _fmt, __vcl_worker_index, ##_args)
 
 #define foreach_vcl_dbg_evt						\
   _(INIT, "vcl init track")						\
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index 1a9bb412fd7..ba9094cd96b 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -485,7 +485,7 @@ void vppcom_send_session_enable_disable (u8 is_enable);
 void vppcom_app_send_attach (void);
 void vppcom_app_send_detach (void);
 void vppcom_send_connect_sock (vcl_session_t * session);
-void vppcom_send_disconnect_session (u64 vpp_handle, u32 session_index);
+void vppcom_send_disconnect_session (u64 vpp_handle);
 void vppcom_send_bind_sock (vcl_session_t * session);
 void vppcom_send_unbind_sock (u64 vpp_handle);
 void vppcom_api_hookup (void);
diff --git a/src/vcl/vcl_test_server.c b/src/vcl/vcl_test_server.c
index 8b8b77fab2c..d1f2db72872 100644
--- a/src/vcl/vcl_test_server.c
+++ b/src/vcl/vcl_test_server.c
@@ -472,10 +472,9 @@ vcl_test_server_handle_cfg (vcl_test_server_worker_t * wrk,
       break;
 
     case SOCK_TEST_TYPE_EXIT:
-      vtinf ("Have a great day conn %d!", conn->fd);
+      vtinf ("Have a great day conn %d (closing)!", conn->fd);
       vppcom_session_close (conn->fd);
       conn_pool_free (conn);
-      vtinf ("Closed client fd %d", conn->fd);
       wrk->nfds--;
       break;
 
@@ -644,6 +643,7 @@ main (int argc, char **argv)
   clib_mem_init_thread_safe (0, 64 << 20);
   ssm->cfg.port = SOCK_TEST_SERVER_PORT;
   ssm->cfg.workers = 1;
+  ssm->active_workers = 1;
   vcl_test_server_process_opts (ssm, argc, argv);
 
   rv = vppcom_app_create ("vcl_test_server");
@@ -661,7 +661,7 @@ main (int argc, char **argv)
     }
   vcl_test_server_worker_loop (&ssm->workers[0]);
 
-  while (ssm->active_workers)
+  while (ssm->active_workers > 0)
     ;
 
   vppcom_app_destroy ();
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 87f29e35311..60d5eb3539a 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -614,13 +614,13 @@ vppcom_app_attach (void)
 }
 
 static int
-vppcom_session_unbind (u32 session_index)
+vppcom_session_unbind (u32 session_handle)
 {
   vcl_worker_t *wrk = vcl_worker_get_current ();
   vcl_session_t *session = 0;
   u64 vpp_handle;
 
-  session = vcl_session_get (wrk, session_index);
+  session = vcl_session_get_w_handle (wrk, session_handle);
   if (!session)
     return VPPCOM_EBADFD;
 
@@ -630,7 +630,7 @@ vppcom_session_unbind (u32 session_index)
   session->session_state = STATE_DISCONNECT;
 
   VDBG (1, "VCL<%d>: vpp handle 0x%llx, sid %u: sending unbind msg! new state"
-	" 0x%x (%s)", getpid (), vpp_handle, session_index, STATE_DISCONNECT,
+	" 0x%x (%s)", getpid (), vpp_handle, session_handle, STATE_DISCONNECT,
 	vppcom_session_state_str (STATE_DISCONNECT));
   vcl_evt (VCL_EVT_UNBIND, session);
   vppcom_send_unbind_sock (vpp_handle);
@@ -639,7 +639,7 @@ vppcom_session_unbind (u32 session_index)
 }
 
 static int
-vppcom_session_disconnect (u32 session_index)
+vppcom_session_disconnect (u32 session_handle)
 {
   vcl_worker_t *wrk = vcl_worker_get_current ();
   svm_msg_q_t *vpp_evt_q;
@@ -647,18 +647,18 @@ vppcom_session_disconnect (u32 session_index)
   session_state_t state;
   u64 vpp_handle;
 
-  session = vcl_session_get (wrk, session_index);
+  session = vcl_session_get_w_handle (wrk, session_handle);
   vpp_handle = session->vpp_handle;
   state = session->session_state;
 
   VDBG (1, "VCL<%d>: vpp handle 0x%llx, sid %u state 0x%x (%s)", getpid (),
-	vpp_handle, session_index, state, vppcom_session_state_str (state));
+	vpp_handle, session_handle, state, vppcom_session_state_str (state));
 
   if (PREDICT_FALSE (state & STATE_LISTEN))
     {
       clib_warning ("VCL<%d>: ERROR: vpp handle 0x%llx, sid %u: "
 		    "Cannot disconnect a listen socket!",
-		    getpid (), vpp_handle, session_index);
+		    getpid (), vpp_handle, session_handle);
       return VPPCOM_EBADFD;
     }
 
@@ -668,13 +668,13 @@ vppcom_session_disconnect (u32 session_index)
       vcl_send_session_disconnected_reply (vpp_evt_q, vcm->my_client_index,
 					   vpp_handle, 0);
       VDBG (1, "VCL<%d>: vpp handle 0x%llx, sid %u: sending disconnect "
-	    "REPLY...", getpid (), vpp_handle, session_index);
+	    "REPLY...", getpid (), vpp_handle, session_handle);
     }
   else
     {
       VDBG (1, "VCL<%d>: vpp handle 0x%llx, sid %u: sending disconnect...",
-	    getpid (), vpp_handle, session_index);
-      vppcom_send_disconnect_session (vpp_handle, session_index);
+	    getpid (), vpp_handle, session_handle);
+      vppcom_send_disconnect_session (vpp_handle);
     }
 
   return VPPCOM_OK;
@@ -1142,7 +1142,7 @@ handle:
   vcl_evt (VCL_EVT_ACCEPT, client_session, listen_session,
 	   client_session_index);
 
-  return client_session_index;
+  return vcl_session_handle (client_session);
 }
 
 int
@@ -1653,6 +1653,12 @@ vcl_select_handle_mq (vcl_worker_t * wrk, svm_msg_q_t * mq,
 	    }
 	  break;
 	case SESSION_IO_EVT_CT_TX:
+	  if (svm_fifo_is_empty (e->fifo))
+	    {
+	      svm_fifo_unset_event (e->fifo);
+	      if (svm_fifo_is_empty (e->fifo))
+		break;
+	    }
 	  session = vcl_ct_session_get_from_fifo (wrk, e->fifo, 0);
 	  sid = session->session_index;
 	  if (sid < n_bits && read_map)
@@ -1977,7 +1983,7 @@ vppcom_epoll_create (void)
   VDBG (0, "VCL<%d>: Created vep_idx %u / sid %u!",
 	getpid (), vep_session->session_index, vep_session->session_index);
 
-  return (vep_session->session_index);
+  return vcl_session_handle (vep_session);
 }
 
 int
@@ -2037,7 +2043,8 @@ vppcom_epoll_ctl (uint32_t vep_handle, int op, uint32_t session_handle,
       if (vep_session->vep.next_sh != ~0)
 	{
 	  vcl_session_t *next_session;
-	  next_session = vcl_session_get (wrk, vep_session->vep.next_sh);
+	  next_session = vcl_session_get_w_handle (wrk,
+						   vep_session->vep.next_sh);
 	  if (PREDICT_FALSE (!next_session))
 	    {
 	      clib_warning ("VCL<%d>: ERROR: EPOLL_CTL_ADD: Invalid "
@@ -2121,7 +2128,7 @@ vppcom_epoll_ctl (uint32_t vep_handle, int op, uint32_t session_handle,
       else
 	{
 	  vcl_session_t *prev_session;
-	  prev_session = vcl_session_get (wrk, session->vep.prev_sh);
+	  prev_session = vcl_session_get_w_handle (wrk, session->vep.prev_sh);
 	  if (PREDICT_FALSE (!prev_session))
 	    {
 	      clib_warning ("VCL<%d>: ERROR: EPOLL_CTL_DEL: Invalid "
@@ -2135,7 +2142,7 @@ vppcom_epoll_ctl (uint32_t vep_handle, int op, uint32_t session_handle,
       if (session->vep.next_sh != ~0)
 	{
 	  vcl_session_t *next_session;
-	  next_session = vcl_session_get (wrk, session->vep.next_sh);
+	  next_session = vcl_session_get_w_handle (wrk, session->vep.next_sh);
 	  if (PREDICT_FALSE (!next_session))
 	    {
 	      clib_warning ("VCL<%d>: ERROR: EPOLL_CTL_DEL: Invalid "
@@ -2314,7 +2321,7 @@ vcl_epoll_wait_handle_mq (vcl_worker_t * wrk, svm_msg_q_t * mq,
 	  session_events = session->vep.ev.events;
 	  break;
 	default:
-	  clib_warning ("unhandled: %u", e->event_type);
+	  VDBG (0, "unhandled: %u", e->event_type);
 	  svm_msg_q_free_msg (mq, msg);
 	  continue;
 	}
diff --git a/src/vnet/session/application.c b/src/vnet/session/application.c
index b7498d00881..8cf32896631 100644
--- a/src/vnet/session/application.c
+++ b/src/vnet/session/application.c
@@ -20,6 +20,56 @@
 
 static app_main_t app_main;
 
+static app_listener_t *
+app_listener_alloc (application_t * app)
+{
+  app_listener_t *app_listener;
+  pool_get (app->listeners, app_listener);
+  memset (app_listener, 0, sizeof (*app_listener));
+  app_listener->al_index = app_listener - app->listeners;
+  return app_listener;
+}
+
+static app_listener_t *
+app_listener_get (application_t * app, u32 app_listener_index)
+{
+  return pool_elt_at_index (app->listeners, app_listener_index);
+}
+
+static void
+app_listener_free (application_t * app, app_listener_t * app_listener)
+{
+  clib_bitmap_free (app_listener->workers);
+  pool_put (app->listeners, app_listener);
+  if (CLIB_DEBUG)
+    memset (app_listener, 0xfa, sizeof (*app_listener));
+}
+
+static app_listener_t *
+app_local_listener_alloc (application_t * app)
+{
+  app_listener_t *app_listener;
+  pool_get (app->local_listeners, app_listener);
+  memset (app_listener, 0, sizeof (*app_listener));
+  app_listener->al_index = app_listener - app->local_listeners;
+  return app_listener;
+}
+
+static app_listener_t *
+app_local_listener_get (application_t * app, u32 app_listener_index)
+{
+  return pool_elt_at_index (app->local_listeners, app_listener_index);
+}
+
+static void
+app_local_listener_free (application_t * app, app_listener_t * app_listener)
+{
+  clib_bitmap_free (app_listener->workers);
+  pool_put (app->local_listeners, app_listener);
+  if (CLIB_DEBUG)
+    memset (app_listener, 0xfa, sizeof (*app_listener));
+}
+
 static app_worker_map_t *
 app_worker_map_alloc (application_t * app)
 {
@@ -95,6 +145,16 @@ application_local_session_table (application_t * app)
   return app_ns->local_table_index;
 }
 
+static void
+application_local_listener_session_endpoint (local_session_t * ll,
+					     session_endpoint_t * sep)
+{
+  sep->transport_proto =
+    session_type_transport_proto (ll->listener_session_type);
+  sep->port = ll->port;
+  sep->is_ip4 = ll->listener_session_type & 1;
+}
+
 int
 application_api_queue_is_full (application_t * app)
 {
@@ -329,6 +389,9 @@ application_free (application_t * app)
 {
   app_worker_map_t *wrk_map;
   app_worker_t *app_wrk;
+  u32 table_index;
+  local_session_t *ll;
+  session_endpoint_t sep;
 
   /*
    * The app event queue allocated in first segment is cleared with
@@ -340,6 +403,10 @@ application_free (application_t * app)
   if (application_is_proxy (app))
     application_remove_proxy (app);
 
+  /*
+   * Free workers
+   */
+
   /* *INDENT-OFF* */
   pool_flush (wrk_map, app->worker_maps, ({
     app_wrk = app_worker_get (wrk_map->wrk_index);
@@ -348,6 +415,24 @@ application_free (application_t * app)
   /* *INDENT-ON* */
   pool_free (app->worker_maps);
 
+  /*
+   * Free local listeners. Global table unbinds stop local listeners
+   * as well, but if we have only local binds, these won't be cleaned up.
+   * Don't bother with local accepted sessions, we clean them when
+   * cleaning up the worker.
+   */
+  table_index = application_local_session_table (app);
+  /* *INDENT-OFF* */
+  pool_foreach (ll, app->local_listen_sessions, ({
+    application_local_listener_session_endpoint (ll, &sep);
+    session_lookup_del_session_endpoint (table_index, &sep);
+  }));
+  /* *INDENT-ON* */
+  pool_free (app->local_listen_sessions);
+
+  /*
+   * Cleanup remaining state
+   */
   application_table_del (app);
   vec_free (app->name);
   vec_free (app->tls_cert);
@@ -372,6 +457,29 @@ application_get_default_worker (application_t * app)
 }
 
 app_worker_t *
+application_listener_select_worker (stream_session_t * ls, u8 is_local)
+{
+  app_listener_t *app_listener;
+  application_t *app;
+  u32 wrk_index;
+
+  app = application_get (ls->app_index);
+  if (!is_local)
+    app_listener = app_listener_get (app, ls->listener_db_index);
+  else
+    app_listener = app_local_listener_get (app, ls->listener_db_index);
+
+  wrk_index = clib_bitmap_next_set (app_listener->workers,
+				    app_listener->accept_rotor + 1);
+  if (wrk_index == ~0)
+    wrk_index = clib_bitmap_first_set (app_listener->workers);
+
+  ASSERT (wrk_index != ~0);
+  app_listener->accept_rotor = wrk_index;
+  return application_get_worker (app, wrk_index);
+}
+
+app_worker_t *
 app_worker_alloc (application_t * app)
 {
   app_worker_t *app_wrk;
@@ -427,7 +535,7 @@ app_worker_free (app_worker_t * app_wrk)
   for (i = 0; i < vec_len (handles); i++)
     {
       a->app_index = app->app_index;
-      a->app_wrk_index = app_wrk->wrk_map_index;
+      a->wrk_map_index = app_wrk->wrk_map_index;
       a->handle = handles[i];
       /* seg manager is removed when unbind completes */
       vnet_unbind (a);
@@ -461,7 +569,7 @@ app_worker_free (app_worker_t * app_wrk)
   /*
    * Local sessions
    */
-  application_local_sessions_free (app_wrk);
+  app_worker_local_sessions_free (app_wrk);
 
   pool_put (app_main.workers, app_wrk);
   if (CLIB_DEBUG)
@@ -516,8 +624,18 @@ app_worker_alloc_and_init (application_t * app, app_worker_t ** wrk)
   return 0;
 }
 
+application_t *
+app_worker_get_app (u32 wrk_index)
+{
+  app_worker_t *app_wrk;
+  app_wrk = app_worker_get_if_valid (wrk_index);
+  if (!app_wrk)
+    return 0;
+  return application_get_if_valid (app_wrk->app_index);
+}
+
 static segment_manager_t *
-application_alloc_segment_manager (app_worker_t * app_wrk)
+app_worker_alloc_segment_manager (app_worker_t * app_wrk)
 {
   segment_manager_t *sm = 0;
 
@@ -536,6 +654,59 @@ application_alloc_segment_manager (app_worker_t * app_wrk)
   return sm;
 }
 
+int
+app_worker_start_listen (app_worker_t * app_wrk, stream_session_t * ls)
+{
+  segment_manager_t *sm;
+
+  /* Allocate segment manager. All sessions derived out of a listen session
+   * have fifos allocated by the same segment manager. */
+  if (!(sm = app_worker_alloc_segment_manager (app_wrk)))
+    return -1;
+
+  /* Add to app's listener table. Useful to find all child listeners
+   * when app goes down, although, just for unbinding this is not needed */
+  hash_set (app_wrk->listeners_table, listen_session_get_handle (ls),
+	    segment_manager_index (sm));
+
+  if (!ls->server_rx_fifo
+      && session_transport_service_type (ls) == TRANSPORT_SERVICE_CL)
+    {
+      if (session_alloc_fifos (sm, ls))
+	return -1;
+    }
+  return 0;
+}
+
+int
+app_worker_stop_listen (app_worker_t * app_wrk, session_handle_t handle)
+{
+  segment_manager_t *sm;
+  uword *sm_indexp;
+
+  sm_indexp = hash_get (app_wrk->listeners_table, handle);
+  if (PREDICT_FALSE (!sm_indexp))
+    {
+      clib_warning ("listener handle was removed %llu!", handle);
+      return -1;
+    }
+
+  sm = segment_manager_get (*sm_indexp);
+  if (app_wrk->first_segment_manager == *sm_indexp)
+    {
+      /* Delete sessions but don't remove segment manager */
+      app_wrk->first_segment_manager_in_use = 0;
+      segment_manager_del_sessions (sm);
+    }
+  else
+    {
+      segment_manager_init_del (sm);
+    }
+  hash_unset (app_wrk->listeners_table, handle);
+
+  return 0;
+}
+
 /**
  * Start listening local transport endpoint for requested transport.
  *
@@ -544,40 +715,75 @@ application_alloc_segment_manager (app_worker_t * app_wrk)
  * it's own specific listening connection.
  */
 int
-app_worker_start_listen (app_worker_t * app_wrk, session_endpoint_t * sep,
-			 session_handle_t * res)
+application_start_listen (application_t * app,
+			  session_endpoint_extended_t * sep_ext,
+			  session_handle_t * res)
 {
-  segment_manager_t *sm;
-  stream_session_t *s;
-  session_handle_t handle;
+  app_listener_t *app_listener;
+  u32 table_index, fib_proto;
+  session_endpoint_t *sep;
+  app_worker_t *app_wrk;
+  stream_session_t *ls;
+  session_handle_t lh;
   session_type_t sst;
 
-  sst = session_type_from_proto_and_ip (sep->transport_proto, sep->is_ip4);
-  s = listen_session_new (0, sst);
-  s->app_wrk_index = app_wrk->wrk_index;
+  /*
+   * Check if sep is already listened on
+   */
+  sep = (session_endpoint_t *) sep_ext;
+  fib_proto = session_endpoint_fib_proto (sep);
+  table_index = application_session_table (app, fib_proto);
+  lh = session_lookup_endpoint_listener (table_index, sep, 1);
+  if (lh != SESSION_INVALID_HANDLE)
+    {
+      ls = listen_session_get_from_handle (lh);
+      if (ls->app_index != app->app_index)
+	return VNET_API_ERROR_ADDRESS_IN_USE;
 
-  /* Allocate segment manager. All sessions derived out of a listen session
-   * have fifos allocated by the same segment manager. */
-  if (!(sm = application_alloc_segment_manager (app_wrk)))
-    goto err;
+      app_wrk = app_worker_get (sep_ext->app_wrk_index);
+      if (ls->app_wrk_index == app_wrk->wrk_index)
+	return VNET_API_ERROR_ADDRESS_IN_USE;
 
-  /* Add to app's listener table. Useful to find all child listeners
-   * when app goes down, although, just for unbinding this is not needed */
-  handle = listen_session_get_handle (s);
-  hash_set (app_wrk->listeners_table, handle, segment_manager_index (sm));
+      if (app_worker_start_listen (app_wrk, ls))
+	return -1;
 
-  if (stream_session_listen (s, sep))
-    {
-      segment_manager_del (sm);
-      hash_unset (app_wrk->listeners_table, handle);
-      goto err;
+      app_listener = app_listener_get (app, ls->listener_db_index);
+      app_listener->workers = clib_bitmap_set (app_listener->workers,
+					       app_wrk->wrk_map_index, 1);
+
+      *res = listen_session_get_handle (ls);
+      return 0;
     }
 
-  *res = handle;
+  /*
+   * Allocate new listener for application
+   */
+  sst = session_type_from_proto_and_ip (sep_ext->transport_proto,
+					sep_ext->is_ip4);
+  ls = listen_session_new (0, sst);
+  ls->app_index = app->app_index;
+
+  if (session_listen (ls, sep_ext))
+    goto err;
+
+  app_listener = app_listener_alloc (app);
+  ls->listener_db_index = app_listener->al_index;
+
+  /*
+   * Setup app worker as a listener
+   */
+  app_wrk = app_worker_get (sep_ext->app_wrk_index);
+  ls->app_wrk_index = app_wrk->wrk_index;
+  if (app_worker_start_listen (app_wrk, ls))
+    goto err;
+  app_listener->workers = clib_bitmap_set (app_listener->workers,
+					   app_wrk->wrk_map_index, 1);
+
+  *res = listen_session_get_handle (ls);
   return 0;
 
 err:
-  listen_session_del (s);
+  listen_session_del (ls);
   return -1;
 }
 
@@ -585,48 +791,43 @@ err:
  * Stop listening on session associated to handle
  *
  * @param handle	listener handle
- * @param app_index	index of the app owning the handle. This is used
- * 			only for validating ownership
+ * @param app_index	index of the app owning the handle.
+ * @param app_wrk_index	index of the worker requesting the stop
  */
 int
-app_worker_stop_listen (session_handle_t handle, u32 app_index)
+application_stop_listen (u32 app_index, u32 app_wrk_index,
+			 session_handle_t handle)
 {
+  app_listener_t *app_listener;
   stream_session_t *listener;
-  segment_manager_t *sm;
   app_worker_t *app_wrk;
-  uword *indexp;
+  application_t *app;
 
   listener = listen_session_get_from_handle (handle);
-  app_wrk = app_worker_get (listener->app_wrk_index);
-  if (PREDICT_FALSE (!app_wrk || app_wrk->app_index != app_index))
+  app = application_get (app_index);
+  if (PREDICT_FALSE (!app || app->app_index != listener->app_index))
     {
       clib_warning ("app doesn't own handle %llu!", handle);
       return -1;
     }
-  if (PREDICT_FALSE (hash_get (app_wrk->listeners_table, handle) == 0))
+
+  app_listener = app_listener_get (app, listener->listener_db_index);
+  if (!clib_bitmap_get (app_listener->workers, app_wrk_index))
     {
-      clib_warning ("listener handle was removed %llu!", handle);
-      return -1;
+      clib_warning ("worker not listening on handle %lu", handle);
+      return 0;
     }
 
-  stream_session_stop_listen (listener);
-
-  indexp = hash_get (app_wrk->listeners_table, handle);
-  ASSERT (indexp);
+  app_wrk = application_get_worker (app, app_wrk_index);
+  app_worker_stop_listen (app_wrk, handle);
+  clib_bitmap_set_no_check (app_listener->workers, app_wrk_index, 0);
 
-  sm = segment_manager_get (*indexp);
-  if (app_wrk->first_segment_manager == *indexp)
-    {
-      /* Delete sessions but don't remove segment manager */
-      app_wrk->first_segment_manager_in_use = 0;
-      segment_manager_del_sessions (sm);
-    }
-  else
+  if (clib_bitmap_is_zero (app_listener->workers))
     {
-      segment_manager_init_del (sm);
+      session_stop_listen (listener);
+      app_listener_free (app, app_listener);
+      listen_session_del (listener);
     }
-  hash_unset (app_wrk->listeners_table, handle);
-  listen_session_del (listener);
 
   return 0;
 }
@@ -653,7 +854,7 @@ app_worker_alloc_connects_segment_manager (app_worker_t * app_wrk)
 
   if (app_wrk->connects_seg_manager == APP_INVALID_SEGMENT_MANAGER_INDEX)
     {
-      sm = application_alloc_segment_manager (app_wrk);
+      sm = app_worker_alloc_segment_manager (app_wrk);
       if (sm == 0)
 	return -1;
       app_wrk->connects_seg_manager = segment_manager_index (sm);
@@ -702,6 +903,7 @@ vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a)
       a->segment = &fs->ssvm;
       segment_manager_segment_reader_unlock (sm);
       a->evt_q = app_wrk->event_queue;
+      a->wrk_index = app_wrk->wrk_map_index;
     }
   else
     {
@@ -808,7 +1010,7 @@ app_worker_first_listener (app_worker_t * app, u8 fib_proto,
    hash_foreach (handle, sm_index, app->listeners_table, ({
      listener = listen_session_get_from_handle (handle);
      if (listener->session_type == sst
-	 && listener->listener_index != SESSION_PROXY_LISTENER_INDEX)
+	 && listener->enqueue_epoch != SESSION_PROXY_LISTENER_INDEX)
        return listener;
    }));
   /* *INDENT-ON* */
@@ -838,7 +1040,7 @@ application_proxy_listener (app_worker_t * app, u8 fib_proto,
    hash_foreach (handle, sm_index, app->listeners_table, ({
      listener = listen_session_get_from_handle (handle);
      if (listener->session_type == sst
-	 && listener->listener_index == SESSION_PROXY_LISTENER_INDEX)
+	 && listener->enqueue_epoch == SESSION_PROXY_LISTENER_INDEX)
        return listener;
    }));
   /* *INDENT-ON* */
@@ -852,7 +1054,7 @@ application_start_stop_proxy_fib_proto (application_t * app, u8 fib_proto,
 {
   app_namespace_t *app_ns = app_namespace_get (app->ns_index);
   u8 is_ip4 = (fib_proto == FIB_PROTOCOL_IP4);
-  session_endpoint_t sep = SESSION_ENDPOINT_NULL;
+  session_endpoint_extended_t sep = SESSION_ENDPOINT_EXT_NULL;
   transport_connection_t *tc;
   app_worker_t *app_wrk;
   stream_session_t *s;
@@ -869,9 +1071,10 @@ application_start_stop_proxy_fib_proto (application_t * app, u8 fib_proto,
 	  sep.fib_index = app_namespace_get_fib_index (app_ns, fib_proto);
 	  sep.sw_if_index = app_ns->sw_if_index;
 	  sep.transport_proto = transport_proto;
-	  app_worker_start_listen (app_wrk, &sep, &handle);
+	  sep.app_wrk_index = app_wrk->wrk_index;	/* only default */
+	  application_start_listen (app, &sep, &handle);
 	  s = listen_session_get_from_handle (handle);
-	  s->listener_index = SESSION_PROXY_LISTENER_INDEX;
+	  s->enqueue_epoch = SESSION_PROXY_LISTENER_INDEX;
 	}
     }
   else
@@ -891,9 +1094,12 @@ application_start_stop_proxy_fib_proto (application_t * app, u8 fib_proto,
       sep.port = 0;
       sti = session_lookup_get_index_for_fib (fib_proto, sep.fib_index);
       if (is_start)
-	session_lookup_add_session_endpoint (sti, &sep, s->session_index);
+	session_lookup_add_session_endpoint (sti,
+					     (session_endpoint_t *) & sep,
+					     s->session_index);
       else
-	session_lookup_del_session_endpoint (sti, &sep);
+	session_lookup_del_session_endpoint (sti,
+					     (session_endpoint_t *) & sep);
     }
 
   return 0;
@@ -1116,33 +1322,33 @@ static app_send_evt_handler_fn * const app_send_evt_handler_fns[3] = {
  * flag is set, we do wait for queue mutex.
  */
 int
-application_send_event (app_worker_t * app, stream_session_t * s, u8 evt_type)
+app_worker_send_event (app_worker_t * app, stream_session_t * s, u8 evt_type)
 {
   ASSERT (app && evt_type <= FIFO_EVENT_APP_TX);
   return app_send_evt_handler_fns[evt_type] (app, s, 0 /* lock */ );
 }
 
 int
-application_lock_and_send_event (app_worker_t * app, stream_session_t * s,
-				 u8 evt_type)
+app_worker_lock_and_send_event (app_worker_t * app, stream_session_t * s,
+				u8 evt_type)
 {
   return app_send_evt_handler_fns[evt_type] (app, s, 1 /* lock */ );
 }
 
 local_session_t *
-application_alloc_local_session (app_worker_t * app)
+application_local_session_alloc (app_worker_t * app_wrk)
 {
   local_session_t *s;
-  pool_get (app->local_sessions, s);
+  pool_get (app_wrk->local_sessions, s);
   memset (s, 0, sizeof (*s));
-  s->app_wrk_index = app->app_index;
-  s->session_index = s - app->local_sessions;
+  s->app_wrk_index = app_wrk->wrk_index;
+  s->session_index = s - app_wrk->local_sessions;
   s->session_type = session_type_from_proto_and_ip (TRANSPORT_PROTO_NONE, 0);
   return s;
 }
 
 void
-application_free_local_session (app_worker_t * app, local_session_t * s)
+application_local_session_free (app_worker_t * app, local_session_t * s)
 {
   pool_put (app->local_sessions, s);
   if (CLIB_DEBUG)
@@ -1170,54 +1376,79 @@ application_get_local_session_from_handle (session_handle_t handle)
 }
 
 local_session_t *
-application_get_local_listen_session_from_handle (session_handle_t lh)
+application_local_listen_session_alloc (application_t * app)
 {
-  u32 ll_index, server_wrk_index;
-  app_worker_t *server_wrk;
+  local_session_t *ll;
+  pool_get (app->local_listen_sessions, ll);
+  memset (ll, 0, sizeof (*ll));
+  return ll;
+}
 
-  local_session_parse_handle (lh, &server_wrk_index, &ll_index);
-  server_wrk = app_worker_get (server_wrk_index);
-  return application_get_local_listen_session (server_wrk, ll_index);
+u32
+application_local_listener_index (application_t * app, local_session_t * ll)
+{
+  return (ll - app->local_listen_sessions);
 }
 
-always_inline void
-application_local_listener_session_endpoint (local_session_t * ll,
-					     session_endpoint_t * sep)
+void
+application_local_listen_session_free (application_t * app,
+				       local_session_t * ll)
 {
-  sep->transport_proto =
-    session_type_transport_proto (ll->listener_session_type);
-  sep->port = ll->port;
-  sep->is_ip4 = ll->listener_session_type & 1;
+  pool_put (app->local_listen_sessions, ll);
+  if (CLIB_DEBUG)
+    memset (ll, 0xfb, sizeof (*ll));
 }
 
 int
-application_start_local_listen (app_worker_t * app_wrk,
-				session_endpoint_t * sep,
+application_start_local_listen (application_t * app,
+				session_endpoint_extended_t * sep_ext,
 				session_handle_t * handle)
 {
+  app_listener_t *app_listener;
+  session_endpoint_t *sep;
+  app_worker_t *app_wrk;
   session_handle_t lh;
   local_session_t *ll;
-  application_t *app;
   u32 table_index;
 
-  app = application_get (app_wrk->app_index);
+  sep = (session_endpoint_t *) sep_ext;
   table_index = application_local_session_table (app);
+  app_wrk = app_worker_get (sep_ext->app_wrk_index);
 
   /* An exact sep match, as opposed to session_lookup_local_listener */
   lh = session_lookup_endpoint_listener (table_index, sep, 1);
   if (lh != SESSION_INVALID_HANDLE)
-    return VNET_API_ERROR_ADDRESS_IN_USE;
+    {
+      ll = application_get_local_listener_w_handle (lh);
+      if (ll->app_index != app->app_index)
+	return VNET_API_ERROR_ADDRESS_IN_USE;
 
-  pool_get (app_wrk->local_listen_sessions, ll);
-  memset (ll, 0, sizeof (*ll));
+      if (ll->app_wrk_index == app_wrk->wrk_index)
+	return VNET_API_ERROR_ADDRESS_IN_USE;
+
+      app_listener = app_local_listener_get (app, ll->listener_db_index);
+      app_listener->workers = clib_bitmap_set (app_listener->workers,
+					       app_wrk->wrk_map_index, 1);
+      *handle = application_local_session_handle (ll);
+      return 0;
+    }
+
+  ll = application_local_listen_session_alloc (app);
   ll->session_type = session_type_from_proto_and_ip (TRANSPORT_PROTO_NONE, 0);
   ll->app_wrk_index = app_wrk->app_index;
-  ll->session_index = ll - app_wrk->local_listen_sessions;
-  ll->port = sep->port;
+  ll->session_index = application_local_listener_index (app, ll);
+  ll->port = sep_ext->port;
   /* Store the original session type for the unbind */
   ll->listener_session_type =
-    session_type_from_proto_and_ip (sep->transport_proto, sep->is_ip4);
+    session_type_from_proto_and_ip (sep_ext->transport_proto,
+				    sep_ext->is_ip4);
   ll->transport_listener_index = ~0;
+  ll->app_index = app->app_index;
+
+  app_listener = app_local_listener_alloc (app);
+  ll->listener_db_index = app_listener->al_index;
+  app_listener->workers = clib_bitmap_set (app_listener->workers,
+					   app_wrk->wrk_map_index, 1);
 
   *handle = application_local_session_handle (ll);
   session_lookup_add_session_endpoint (table_index, sep, *handle);
@@ -1231,10 +1462,12 @@ application_start_local_listen (app_worker_t * app_wrk,
  * so parse it.
  */
 int
-application_stop_local_listen (session_handle_t lh, u32 app_index)
+application_stop_local_listen (u32 app_index, u32 wrk_map_index,
+			       session_handle_t lh)
 {
   session_endpoint_t sep = SESSION_ENDPOINT_NULL;
-  u32 table_index, ll_index, server_wrk_index;
+  u32 table_index, ll_index, server_index;
+  app_listener_t *app_listener;
   app_worker_t *server_wrk;
   stream_session_t *sl = 0;
   local_session_t *ll, *ls;
@@ -1259,28 +1492,44 @@ application_stop_local_listen (session_handle_t lh, u32 app_index)
 	return -1;
     }
 
-  local_session_parse_handle (lh, &server_wrk_index, &ll_index);
-  server_wrk = app_worker_get (server_wrk_index);
-  if (PREDICT_FALSE (server_wrk->app_index != app_index))
+  local_session_parse_handle (lh, &server_index, &ll_index);
+  if (PREDICT_FALSE (server_index != app_index))
     {
       clib_warning ("app %u does not own local handle 0x%lx", app_index, lh);
+      return -1;
     }
-  ll = application_get_local_listen_session (server_wrk, ll_index);
+
+  ll = application_get_local_listen_session (server, ll_index);
   if (PREDICT_FALSE (!ll))
     {
       clib_warning ("no local listener");
       return -1;
     }
-  application_local_listener_session_endpoint (ll, &sep);
-  session_lookup_del_session_endpoint (table_index, &sep);
 
+  app_listener = app_local_listener_get (server, ll->listener_db_index);
+  if (!clib_bitmap_get (app_listener->workers, wrk_map_index))
+    {
+      clib_warning ("app wrk %u not listening on handle %lu", wrk_map_index,
+		    lh);
+      return -1;
+    }
+
+  server_wrk = application_get_worker (server, wrk_map_index);
   /* *INDENT-OFF* */
   pool_foreach (ls, server_wrk->local_sessions, ({
     if (ls->listener_index == ll->session_index)
       application_local_session_disconnect (server_wrk->app_index, ls);
   }));
   /* *INDENT-ON* */
-  pool_put_index (server_wrk->local_listen_sessions, ll->session_index);
+
+  clib_bitmap_set_no_check (app_listener->workers, wrk_map_index, 0);
+  if (clib_bitmap_is_zero (app_listener->workers))
+    {
+      app_local_listener_free (server, app_listener);
+      application_local_listener_session_endpoint (ll, &sep);
+      session_lookup_del_session_endpoint (table_index, &sep);
+      application_local_listen_session_free (server, ll);
+    }
 
   return 0;
 }
@@ -1317,8 +1566,7 @@ application_local_session_connect (app_worker_t * client_wrk,
   local_session_t *ls;
   svm_msg_q_t *sq, *cq;
 
-  ls = application_alloc_local_session (server_wrk);
-
+  ls = application_local_session_alloc (server_wrk);
   server = application_get (server_wrk->app_index);
   client = application_get (client_wrk->app_index);
 
@@ -1380,6 +1628,7 @@ application_local_session_connect (app_worker_t * client_wrk,
   ls->client_wrk_index = client_wrk->wrk_index;
   ls->client_opaque = opaque;
   ls->listener_session_type = ll->session_type;
+  ls->session_state = SESSION_STATE_READY;
 
   if ((rv = server->cb_fns.add_segment_callback (server->api_client_index,
 						 &seg->ssvm)))
@@ -1495,24 +1744,41 @@ application_local_session_cleanup (app_worker_t * client_wrk,
       segment_manager_del_segment (sm, seg);
     }
 
-  application_free_local_session (server_wrk, ls);
+  application_local_session_free (server_wrk, ls);
 
   return 0;
 }
 
 int
-application_local_session_disconnect (u32 app_wrk_index, local_session_t * ls)
+application_local_session_disconnect (u32 app_index, local_session_t * ls)
 {
   app_worker_t *client_wrk, *server_wrk;
+  u8 is_server = 0, is_client = 0;
+  application_t *app;
+
+  app = application_get_if_valid (app_index);
+  if (!app)
+    return 0;
 
   client_wrk = app_worker_get_if_valid (ls->client_wrk_index);
   server_wrk = app_worker_get (ls->app_wrk_index);
 
+  if (server_wrk->app_index == app_index)
+    is_server = 1;
+  else if (client_wrk && client_wrk->app_index == app_index)
+    is_client = 1;
+
+  if (!is_server && !is_client)
+    {
+      clib_warning ("app %u is neither client nor server for session 0x%lx",
+		    app_index, application_local_session_handle (ls));
+      return VNET_API_ERROR_INVALID_VALUE;
+    }
 
   if (ls->session_state == SESSION_STATE_CLOSED)
     return application_local_session_cleanup (client_wrk, server_wrk, ls);
 
-  if (app_wrk_index == ls->client_wrk_index)
+  if (app_index == ls->client_wrk_index)
     {
       mq_send_local_session_disconnected_cb (ls->app_wrk_index, ls);
     }
@@ -1556,30 +1822,16 @@ application_local_session_disconnect_w_index (u32 app_wrk_index, u32 ls_index)
 }
 
 void
-application_local_sessions_free (app_worker_t * app_wrk)
+app_worker_local_sessions_free (app_worker_t * app_wrk)
 {
-  u32 index, server_wrk_index, session_index, table_index;
-  segment_manager_t *sm;
+  u32 index, server_wrk_index, session_index;
   u64 handle, *handles = 0;
-  local_session_t *ls, *ll;
   app_worker_t *server_wrk;
-  session_endpoint_t sep;
-  application_t *app;
+  segment_manager_t *sm;
+  local_session_t *ls;
   int i;
 
   /*
-   * Local listens. Don't bother with local sessions, we clean them lower
-   */
-  app = application_get (app_wrk->app_index);
-  table_index = application_local_session_table (app);
-  /* *INDENT-OFF* */
-  pool_foreach (ll, app_wrk->local_listen_sessions, ({
-    application_local_listener_session_endpoint (ll, &sep);
-    session_lookup_del_session_endpoint (table_index, &sep);
-  }));
-  /* *INDENT-ON* */
-
-  /*
    * Local sessions
    */
   if (app_wrk->local_sessions)
@@ -1657,10 +1909,10 @@ format_app_worker_listener (u8 * s, va_list * args)
   if (!app_wrk)
     {
       if (verbose)
-	s = format (s, "%-40s%-25s%-15s%-15s%-10s", "Connection", "App",
-		    "API Client", "ListenerID", "SegManager");
+	s = format (s, "%-40s%-25s%=10s%-15s%-15s%-10s", "Connection", "App",
+		    "Wrk", "API Client", "ListenerID", "SegManager");
       else
-	s = format (s, "%-40s%-25s", "Connection", "App");
+	s = format (s, "%-40s%-25s%=10s", "Connection", "App", "Wrk");
 
       return s;
     }
@@ -1672,11 +1924,12 @@ format_app_worker_listener (u8 * s, va_list * args)
 
   if (verbose)
     {
-      s = format (s, "%-40s%-25s%-15u%-15u%-10u", str, app_name,
-		  app->api_client_index, handle, sm_index);
+      s = format (s, "%-40s%-25s%=10u%-15u%-15u%-10u", str, app_name,
+		  app_wrk->wrk_map_index, app->api_client_index, handle,
+		  sm_index);
     }
   else
-    s = format (s, "%-40s%-25s", str, app_name);
+    s = format (s, "%-40s%-25s%=10u", str, app_name, app_wrk->wrk_map_index);
 
   vec_free (app_name);
   return s;
@@ -1817,13 +2070,6 @@ app_worker_format_local_sessions (app_worker_t * app_wrk, int verbose)
     return;
 
   /* *INDENT-OFF* */
-  pool_foreach (ls, app_wrk->local_listen_sessions, ({
-    tp = session_type_transport_proto(ls->listener_session_type);
-    conn = format (0, "[L][%U] *:%u", format_transport_proto_short, tp,
-                   ls->port);
-    vlib_cli_output (vm, "%-40v%-15u%-20s", conn, ls->app_wrk_index, "*");
-    vec_reset_length (conn);
-  }));
   pool_foreach (ls, app_wrk->local_sessions, ({
     tp = session_type_transport_proto(ls->listener_session_type);
     conn = format (0, "[L][%U] *:%u", format_transport_proto_short, tp,
@@ -1840,8 +2086,12 @@ app_worker_format_local_sessions (app_worker_t * app_wrk, int verbose)
 static void
 application_format_local_sessions (application_t * app, int verbose)
 {
+  vlib_main_t *vm = vlib_get_main ();
   app_worker_map_t *wrk_map;
   app_worker_t *app_wrk;
+  transport_proto_t tp;
+  local_session_t *ls;
+  u8 *conn = 0;
 
   if (!app)
     {
@@ -1849,6 +2099,23 @@ application_format_local_sessions (application_t * app, int verbose)
       return;
     }
 
+  /*
+   * Format local listeners
+   */
+
+  /* *INDENT-OFF* */
+  pool_foreach (ls, app->local_listen_sessions, ({
+    tp = session_type_transport_proto (ls->listener_session_type);
+    conn = format (0, "[L][%U] *:%u", format_transport_proto_short, tp,
+                   ls->port);
+    vlib_cli_output (vm, "%-40v%-15u%-20s", conn, ls->app_wrk_index, "*");
+    vec_reset_length (conn);
+  }));
+  /* *INDENT-ON* */
+
+  /*
+   * Format local accepted/connected sessions
+   */
   /* *INDENT-OFF* */
   pool_foreach (wrk_map, app->worker_maps, ({
     app_wrk = app_worker_get (wrk_map->wrk_index);
diff --git a/src/vnet/session/application.h b/src/vnet/session/application.h
index de609d2d7a0..e83b7a6ba6e 100644
--- a/src/vnet/session/application.h
+++ b/src/vnet/session/application.h
@@ -60,6 +60,8 @@ typedef struct _stream_session_cb_vft
 
 typedef struct app_worker_
 {
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
+
   /** Worker index in global worker pool*/
   u32 wrk_index;
 
@@ -93,9 +95,6 @@ typedef struct app_worker_
   /** Segment manager used for incoming "cut through" connects */
   u32 local_segment_manager;
 
-  /** Pool of local listen sessions */
-  local_session_t *local_listen_sessions;
-
   /** Pool of local sessions the app owns (as a server) */
   local_session_t *local_sessions;
 
@@ -110,6 +109,13 @@ typedef struct app_worker_map_
   u32 wrk_index;
 } app_worker_map_t;
 
+typedef struct app_listener_
+{
+  clib_bitmap_t *workers;	/**< workers accepting connections */
+  u32 accept_rotor;		/**< last worker to accept a connection */
+  u32 al_index;
+} app_listener_t;
+
 typedef struct application_
 {
   /** App index in app pool */
@@ -138,6 +144,15 @@ typedef struct application_
 
   u16 proxied_transports;
 
+  /** Pool of listeners for the app */
+  app_listener_t *listeners;
+
+  /** Pool of local listeners for app */
+  app_listener_t *local_listeners;
+
+  /** Pool of local listen sessions */
+  local_session_t *local_listen_sessions;
+
   /*
    * TLS Specific
    */
@@ -150,6 +165,7 @@ typedef struct application_
 
   /** Preferred tls engine */
   u8 tls_engine;
+
 } application_t;
 
 typedef struct app_main_
@@ -207,11 +223,8 @@ app_worker_t *app_worker_alloc (application_t * app);
 int app_worker_alloc_and_init (application_t * app, app_worker_t ** wrk);
 app_worker_t *app_worker_get (u32 wrk_index);
 app_worker_t *app_worker_get_if_valid (u32 wrk_index);
+application_t *app_worker_get_app (u32 wrk_index);
 void app_worker_free (app_worker_t * app_wrk);
-int app_worker_start_listen (app_worker_t * app,
-			     session_endpoint_t * tep,
-			     session_handle_t * handle);
-int app_worker_stop_listen (session_handle_t handle, u32 app_wrk_index);
 int app_worker_open_session (app_worker_t * app, session_endpoint_t * tep,
 			     u32 api_context);
 segment_manager_t *app_worker_get_listen_segment_manager (app_worker_t *,
@@ -224,8 +237,17 @@ stream_session_t *app_worker_first_listener (app_worker_t * app,
 					     u8 fib_proto,
 					     u8 transport_proto);
 u8 app_worker_application_is_builtin (app_worker_t * app_wrk);
+int app_worker_send_event (app_worker_t * app, stream_session_t * s, u8 evt);
+int app_worker_lock_and_send_event (app_worker_t * app, stream_session_t * s,
+				    u8 evt_type);
 clib_error_t *vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a);
 
+int application_start_listen (application_t * app,
+			      session_endpoint_extended_t * tep,
+			      session_handle_t * handle);
+int application_stop_listen (u32 app_index, u32 app_wrk_index,
+			     session_handle_t handle);
+
 application_t *application_alloc (void);
 int application_alloc_and_init (app_init_args_t * args);
 void application_free (application_t * app);
@@ -236,8 +258,10 @@ application_t *application_lookup_name (const u8 * name);
 u32 application_index (application_t * app);
 app_worker_t *application_get_worker (application_t * app, u32 wrk_index);
 app_worker_t *application_get_default_worker (application_t * app);
-int application_api_queue_is_full (application_t * app);
+app_worker_t *application_listener_select_worker (stream_session_t * ls,
+						  u8 is_local);
 
+int application_api_queue_is_full (application_t * app);
 
 int application_is_proxy (application_t * app);
 int application_is_builtin (application_t * app);
@@ -252,12 +276,17 @@ void application_setup_proxy (application_t * app);
 void application_remove_proxy (application_t * app);
 
 segment_manager_properties_t *application_get_segment_manager_properties (u32
-									  app_wrk_index);
+									  app_index);
+
 segment_manager_properties_t
   * application_segment_manager_properties (application_t * app);
 
-local_session_t *application_alloc_local_session (app_worker_t * app);
-void application_free_local_session (app_worker_t * app,
+/*
+ * Local session
+ */
+
+local_session_t *application_local_session_alloc (app_worker_t * app);
+void application_local_session_free (app_worker_t * app,
 				     local_session_t * ls);
 local_session_t *application_get_local_session (app_worker_t * app,
 						u32 session_index);
@@ -265,29 +294,39 @@ local_session_t *application_get_local_session_from_handle (session_handle_t
 							    handle);
 local_session_t
   * application_get_local_listen_session_from_handle (session_handle_t lh);
-int application_start_local_listen (app_worker_t * server,
-				    session_endpoint_t * sep,
+int application_start_local_listen (application_t * server,
+				    session_endpoint_extended_t * sep,
 				    session_handle_t * handle);
-int application_stop_local_listen (session_handle_t lh, u32 app_wrk_index);
+int application_stop_local_listen (u32 app_index, u32 app_wrk_index,
+				   session_handle_t lh);
 int application_local_session_connect (app_worker_t * client,
 				       app_worker_t * server,
-				       local_session_t * ll, u32 opaque);
+				       local_session_t * ls, u32 opaque);
 int application_local_session_connect_notify (local_session_t * ls);
 int application_local_session_disconnect (u32 app_wrk_index,
 					  local_session_t * ls);
 int application_local_session_disconnect_w_index (u32 app_wrk_index,
 						  u32 ls_index);
-void application_local_sessions_free (app_worker_t * app);
-
-int application_send_event (app_worker_t * app, stream_session_t * s, u8 evt);
-int application_lock_and_send_event (app_worker_t * app,
-				     stream_session_t * s, u8 evt_type);
+void app_worker_local_sessions_free (app_worker_t * app);
 
 always_inline u32
-local_session_id (local_session_t * ll)
+local_session_id (local_session_t * ls)
 {
-  ASSERT (ll->app_wrk_index < (2 << 16) && ll->session_index < (2 << 16));
-  return ((u32) ll->app_wrk_index << 16 | (u32) ll->session_index);
+  ASSERT (ls->session_index < (2 << 16));
+  u32 app_or_wrk_index;
+
+  if (ls->session_state == SESSION_STATE_LISTENING)
+    {
+      ASSERT (ls->app_index < (2 << 16));
+      app_or_wrk_index = ls->app_index;
+    }
+  else
+    {
+      ASSERT (ls->app_wrk_index < (2 << 16));
+      app_or_wrk_index = ls->app_wrk_index;
+    }
+
+  return ((u32) app_or_wrk_index << 16 | (u32) ls->session_index);
 }
 
 always_inline void
@@ -315,7 +354,7 @@ application_local_session_handle (local_session_t * ls)
 }
 
 always_inline local_session_t *
-application_get_local_listen_session (app_worker_t * app, u32 session_index)
+application_get_local_listen_session (application_t * app, u32 session_index)
 {
   return pool_elt_at_index (app->local_listen_sessions, session_index);
 }
@@ -323,10 +362,10 @@ application_get_local_listen_session (app_worker_t * app, u32 session_index)
 always_inline local_session_t *
 application_get_local_listener_w_handle (session_handle_t handle)
 {
-  u32 server_wrk_index, session_index;
-  app_worker_t *app;
-  local_session_parse_handle (handle, &server_wrk_index, &session_index);
-  app = app_worker_get (server_wrk_index);
+  u32 server_index, session_index;
+  application_t *app;
+  local_session_parse_handle (handle, &server_index, &session_index);
+  app = application_get (server_index);
   return application_get_local_listen_session (app, session_index);
 }
 
diff --git a/src/vnet/session/application_interface.c b/src/vnet/session/application_interface.c
index 2e631363016..ab87def4062 100644
--- a/src/vnet/session/application_interface.c
+++ b/src/vnet/session/application_interface.c
@@ -147,11 +147,10 @@ session_endpoint_update_for_app (session_endpoint_t * sep,
     }
 }
 
-static int
-vnet_bind_i (vnet_bind_args_t * a)
+static inline int
+vnet_bind_inline (vnet_bind_args_t * a)
 {
-  u64 lh, ll_handle = SESSION_INVALID_HANDLE;
-  u32 table_index, fib_proto;
+  u64 ll_handle = SESSION_INVALID_HANDLE;
   app_worker_t *app_wrk;
   application_t *app;
   int rv;
@@ -163,17 +162,12 @@ vnet_bind_i (vnet_bind_args_t * a)
       return VNET_API_ERROR_APPLICATION_NOT_ATTACHED;
     }
   app_wrk = application_get_worker (app, a->wrk_map_index);
+  a->sep_ext.app_wrk_index = app_wrk->wrk_index;
 
   session_endpoint_update_for_app (&a->sep, app);
   if (!session_endpoint_in_ns (&a->sep))
     return VNET_API_ERROR_INVALID_VALUE_2;
 
-  fib_proto = session_endpoint_fib_proto (&a->sep);
-  table_index = application_session_table (app, fib_proto);
-  lh = session_lookup_endpoint_listener (table_index, &a->sep, 1);
-  if (lh != SESSION_INVALID_HANDLE)
-    return VNET_API_ERROR_ADDRESS_IN_USE;
-
   /*
    * Add session endpoint to local session table. Only binds to "inaddr_any"
    * (i.e., zero address) are added to local scope table.
@@ -181,8 +175,8 @@ vnet_bind_i (vnet_bind_args_t * a)
   if (application_has_local_scope (app)
       && session_endpoint_is_local (&a->sep))
     {
-      if ((rv =
-	   application_start_local_listen (app_wrk, &a->sep, &a->handle)))
+      if ((rv = application_start_local_listen (app, &a->sep_ext,
+						&a->handle)))
 	return rv;
       ll_handle = a->handle;
     }
@@ -195,13 +189,17 @@ vnet_bind_i (vnet_bind_args_t * a)
    */
 
   /* Setup listen path down to transport */
-  rv = app_worker_start_listen (app_wrk, &a->sep, &a->handle);
+  rv = application_start_listen (app, &a->sep_ext, &a->handle);
   if (rv && ll_handle != SESSION_INVALID_HANDLE)
-    session_lookup_del_session_endpoint (table_index, &a->sep);
+    {
+      application_stop_local_listen (a->app_index, a->wrk_map_index,
+				     ll_handle);
+      return rv;
+    }
 
   /*
    * Store in local table listener the index of the transport layer
-   * listener. We'll need local listeners are hit and we need to
+   * listener. We'll need if if local listeners are hit and we need to
    * return global handle
    */
   if (ll_handle != SESSION_INVALID_HANDLE)
@@ -210,18 +208,19 @@ vnet_bind_i (vnet_bind_args_t * a)
       stream_session_t *tl;
       ll = application_get_local_listener_w_handle (ll_handle);
       tl = listen_session_get_from_handle (a->handle);
-      ll->transport_listener_index = tl->session_index;
+      if (ll->transport_listener_index == ~0)
+	ll->transport_listener_index = tl->session_index;
     }
   return rv;
 }
 
-int
-vnet_unbind_i (u32 app_index, session_handle_t handle)
+static inline int
+vnet_unbind_inline (vnet_unbind_args_t * a)
 {
   application_t *app;
   int rv;
 
-  if (!(app = application_get_if_valid (app_index)))
+  if (!(app = application_get_if_valid (a->app_index)))
     {
       SESSION_DBG ("app (%d) not attached", wrk_map_index);
       return VNET_API_ERROR_APPLICATION_NOT_ATTACHED;
@@ -229,7 +228,8 @@ vnet_unbind_i (u32 app_index, session_handle_t handle)
 
   if (application_has_local_scope (app))
     {
-      if ((rv = application_stop_local_listen (handle, app_index)))
+      if ((rv = application_stop_local_listen (a->app_index,
+					       a->wrk_map_index, a->handle)))
 	return rv;
     }
 
@@ -237,7 +237,8 @@ vnet_unbind_i (u32 app_index, session_handle_t handle)
    * Clear the global scope table of the listener
    */
   if (application_has_global_scope (app))
-    return app_worker_stop_listen (handle, app_index);
+    return application_stop_listen (a->app_index, a->wrk_map_index,
+				    a->handle);
   return 0;
 }
 
@@ -247,7 +248,7 @@ application_connect (vnet_connect_args_t * a)
   app_worker_t *server_wrk, *client_wrk;
   u32 table_index, server_index, li;
   stream_session_t *listener;
-  application_t *client;
+  application_t *client, *server;
   local_session_t *ll;
   u8 fib_proto;
   u64 lh;
@@ -283,8 +284,11 @@ application_connect (vnet_connect_args_t * a)
        */
       if (server_index != a->app_index)
 	{
-	  server_wrk = app_worker_get (server_index);
-	  ll = application_get_local_listen_session (server_wrk, li);
+	  server = application_get (server_index);
+	  ll = application_get_local_listen_session (server, li);
+	  listener = (stream_session_t *) ll;
+	  server_wrk = application_listener_select_worker (listener,
+							   1 /* is_local */ );
 	  return application_local_session_connect (client_wrk,
 						    server_wrk, ll,
 						    a->api_context);
@@ -308,13 +312,11 @@ global_scope:
   listener = session_lookup_listener (table_index, &a->sep);
   if (listener)
     {
-      server_wrk = app_worker_get (listener->app_wrk_index);
-      if (server_wrk)
-	{
-	  ll = (local_session_t *) listener;
-	  return application_local_session_connect (client_wrk, server_wrk,
-						    ll, a->api_context);
-	}
+      server_wrk = application_listener_select_worker (listener,
+						       0 /* is_local */ );
+      ll = (local_session_t *) listener;
+      return application_local_session_connect (client_wrk, server_wrk, ll,
+						a->api_context);
     }
 
   /*
@@ -531,7 +533,7 @@ vnet_bind_uri (vnet_bind_args_t * a)
   if (rv)
     return rv;
   clib_memcpy (&a->sep_ext, &sep, sizeof (sep));
-  return vnet_bind_i (a);
+  return vnet_bind_inline (a);
 }
 
 int
@@ -553,8 +555,8 @@ vnet_unbind_uri (vnet_unbind_args_t * a)
 				      (session_endpoint_t *) & sep);
   if (!listener)
     return VNET_API_ERROR_ADDRESS_NOT_IN_USE;
-
-  return vnet_unbind_i (a->app_index, listen_session_get_handle (listener));
+  a->handle = listen_session_get_handle (listener);
+  return vnet_unbind_inline (a);
 }
 
 clib_error_t *
@@ -592,13 +594,6 @@ vnet_disconnect_session (vnet_disconnect_args_t * a)
       if (!(ls = application_get_local_session_from_handle (a->handle)))
 	return 0;
 
-      if (ls->app_wrk_index != a->app_index
-	  && ls->client_wrk_index != a->app_index)
-	{
-	  clib_warning ("app %u is neither client nor server for session %u",
-			a->app_index, a->app_index);
-	  return VNET_API_ERROR_INVALID_VALUE;
-	}
       return application_local_session_disconnect (a->app_index, ls);
     }
   else
@@ -620,7 +615,7 @@ clib_error_t *
 vnet_bind (vnet_bind_args_t * a)
 {
   int rv;
-  if ((rv = vnet_bind_i (a)))
+  if ((rv = vnet_bind_inline (a)))
     return clib_error_return_code (0, rv, 0, "bind failed: %d", rv);
   return 0;
 }
@@ -629,7 +624,7 @@ clib_error_t *
 vnet_unbind (vnet_unbind_args_t * a)
 {
   int rv;
-  if ((rv = vnet_unbind_i (a->app_index, a->handle)))
+  if ((rv = vnet_unbind_inline (a)))
     return clib_error_return_code (0, rv, 0, "unbind failed: %d", rv);
   return 0;
 }
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index 1f481dcf85e..1eefb0c3860 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -64,7 +64,7 @@ typedef struct _vnet_unbind_args_t
     u64 handle;			/**< Session handle */
   };
   u32 app_index;		/**< Owning application index */
-  u32 app_wrk_index;		/**< App's local pool worker index */
+  u32 wrk_map_index;		/**< App's local pool worker index */
 } vnet_unbind_args_t;
 
 typedef struct _vnet_connect_args
diff --git a/src/vnet/session/segment_manager.c b/src/vnet/session/segment_manager.c
index 158a8e8abf3..83d196358f3 100644
--- a/src/vnet/session/segment_manager.c
+++ b/src/vnet/session/segment_manager.c
@@ -34,7 +34,8 @@ static u32 default_app_evt_queue_size = 128;
 segment_manager_properties_t *
 segment_manager_properties_get (segment_manager_t * sm)
 {
-  return application_get_segment_manager_properties (sm->app_wrk_index);
+  app_worker_t *app_wrk = app_worker_get (sm->app_wrk_index);
+  return application_get_segment_manager_properties (app_wrk->app_index);
 }
 
 segment_manager_properties_t *
diff --git a/src/vnet/session/session.api b/src/vnet/session/session.api
index 24ebfba5dba..aa73212da85 100644
--- a/src/vnet/session/session.api
+++ b/src/vnet/session/session.api
@@ -294,11 +294,13 @@ define bind_sock {
 /** \brief Unbind 
     @param client_index - opaque cookie to identify the sender
     @param context - sender context, to match reply w/ request
+    @param wrk_index - index of worker requesting the bind
     @param handle - bind handle obtained from bind reply
 */
 autoreply define unbind_sock {
   u32 client_index;
   u32 context;
+  u32 wrk_index;
   u64 handle;
 };
 
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index 57ac384a519..952a5a90141 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -505,9 +505,9 @@ session_enqueue_notify (stream_session_t * s, u8 lock)
   /* *INDENT-ON* */
 
   if (lock)
-    return application_lock_and_send_event (app, s, FIFO_EVENT_APP_RX);
+    return app_worker_lock_and_send_event (app, s, FIFO_EVENT_APP_RX);
 
-  return application_send_event (app, s, FIFO_EVENT_APP_RX);
+  return app_worker_send_event (app, s, FIFO_EVENT_APP_RX);
 }
 
 int
@@ -520,9 +520,9 @@ session_dequeue_notify (stream_session_t * s)
     return -1;
 
   if (session_transport_service_type (s) == TRANSPORT_SERVICE_CL)
-    return application_lock_and_send_event (app, s, FIFO_EVENT_APP_RX);
+    return app_worker_lock_and_send_event (app, s, FIFO_EVENT_APP_RX);
 
-  return application_send_event (app, s, FIFO_EVENT_APP_TX);
+  return app_worker_send_event (app, s, FIFO_EVENT_APP_TX);
 }
 
 /**
@@ -971,112 +971,44 @@ session_open (u32 app_wrk_index, session_endpoint_t * rmt, u32 opaque)
   return session_open_srv_fns[tst] (app_wrk_index, rmt, opaque);
 }
 
+/**
+ * Ask transport to listen on session endpoint.
+ *
+ * @param s Session for which listen will be called. Note that unlike
+ * 	    established sessions, listen sessions are not associated to a
+ * 	    thread.
+ * @param sep Local endpoint to be listened on.
+ */
 int
-session_listen_vc (stream_session_t * s, session_endpoint_t * sep)
-{
-  transport_connection_t *tc;
-  u32 tci;
-
-  /* Transport bind/listen  */
-  tci = tp_vfts[sep->transport_proto].bind (s->session_index,
-					    session_endpoint_to_transport
-					    (sep));
-
-  if (tci == (u32) ~ 0)
-    return -1;
-
-  /* Attach transport to session */
-  s->connection_index = tci;
-  tc = tp_vfts[sep->transport_proto].get_listener (tci);
-
-  /* Weird but handle it ... */
-  if (tc == 0)
-    return -1;
-
-  /* Add to the main lookup table */
-  session_lookup_add_connection (tc, s->session_index);
-  return 0;
-}
-
-int
-session_listen_cl (stream_session_t * s, session_endpoint_t * sep)
+session_listen (stream_session_t * ls, session_endpoint_extended_t * sep)
 {
   transport_connection_t *tc;
-  app_worker_t *server;
-  segment_manager_t *sm;
-  u32 tci;
+  transport_endpoint_t *tep;
+  u32 tc_index;
 
-  /* Transport bind/listen  */
-  tci = tp_vfts[sep->transport_proto].bind (s->session_index,
-					    session_endpoint_to_transport
-					    (sep));
+  /* Transport bind/listen */
+  tep = session_endpoint_to_transport (sep);
+  tc_index = tp_vfts[sep->transport_proto].bind (ls->session_index, tep);
 
-  if (tci == (u32) ~ 0)
+  if (tc_index == (u32) ~ 0)
     return -1;
 
   /* Attach transport to session */
-  s->connection_index = tci;
-  tc = tp_vfts[sep->transport_proto].get_listener (tci);
-
-  /* Weird but handle it ... */
-  if (tc == 0)
-    return -1;
-
-  server = app_worker_get (s->app_wrk_index);
-  sm = app_worker_get_listen_segment_manager (server, s);
-  if (session_alloc_fifos (sm, s))
-    return -1;
+  ls->connection_index = tc_index;
 
-  /* Add to the main lookup table */
-  session_lookup_add_connection (tc, s->session_index);
+  /* Add to the main lookup table after transport was initialized */
+  tc = tp_vfts[sep->transport_proto].get_listener (tc_index);
+  session_lookup_add_connection (tc, ls->session_index);
   return 0;
 }
 
-int
-session_listen_app (stream_session_t * s, session_endpoint_t * sep)
-{
-  session_endpoint_extended_t esep;
-  clib_memcpy (&esep, sep, sizeof (*sep));
-  esep.app_wrk_index = s->app_wrk_index;
-
-  return tp_vfts[sep->transport_proto].bind (s->session_index,
-					     (transport_endpoint_t *) & esep);
-}
-
-typedef int (*session_listen_service_fn) (stream_session_t *,
-					  session_endpoint_t *);
-
-/* *INDENT-OFF* */
-static session_listen_service_fn
-session_listen_srv_fns[TRANSPORT_N_SERVICES] = {
-  session_listen_vc,
-  session_listen_cl,
-  session_listen_app,
-};
-/* *INDENT-ON* */
-
-/**
- * Ask transport to listen on local transport endpoint.
- *
- * @param s Session for which listen will be called. Note that unlike
- * 	    established sessions, listen sessions are not associated to a
- * 	    thread.
- * @param tep Local endpoint to be listened on.
- */
-int
-stream_session_listen (stream_session_t * s, session_endpoint_t * sep)
-{
-  transport_service_type_t tst = tp_vfts[sep->transport_proto].service_type;
-  return session_listen_srv_fns[tst] (s, sep);
-}
-
 /**
  * Ask transport to stop listening on local transport endpoint.
  *
  * @param s Session to stop listening on. It must be in state LISTENING.
  */
 int
-stream_session_stop_listen (stream_session_t * s)
+session_stop_listen (stream_session_t * s)
 {
   transport_proto_t tp = session_get_transport_proto (s);
   transport_connection_t *tc;
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index 184fa997736..19609da89e5 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -24,7 +24,7 @@
 
 #define HALF_OPEN_LOOKUP_INVALID_VALUE ((u64)~0)
 #define INVALID_INDEX ((u32)~0)
-#define SESSION_PROXY_LISTENER_INDEX ((u32)~0 - 1)
+#define SESSION_PROXY_LISTENER_INDEX ((u8)~0 - 1)
 #define SESSION_LOCAL_HANDLE_PREFIX 0x7FFFFFFF
 
 /* TODO decide how much since we have pre-data as well */
@@ -550,8 +550,8 @@ void stream_session_reset_notify (transport_connection_t * tc);
 int stream_session_accept (transport_connection_t * tc, u32 listener_index,
 			   u8 notify);
 int session_open (u32 app_index, session_endpoint_t * tep, u32 opaque);
-int stream_session_listen (stream_session_t * s, session_endpoint_t * tep);
-int stream_session_stop_listen (stream_session_t * s);
+int session_listen (stream_session_t * s, session_endpoint_extended_t * sep);
+int session_stop_listen (stream_session_t * s);
 void stream_session_disconnect (stream_session_t * s);
 void stream_session_disconnect_transport (stream_session_t * s);
 void stream_session_cleanup (stream_session_t * s);
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index 78c05c34431..aa29090383a 100755
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -255,7 +255,7 @@ send_session_accept_callback (stream_session_t * s)
 	}
       else
 	{
-	  ll = application_get_local_listen_session (server_wrk,
+	  ll = application_get_local_listen_session (server,
 						     ls->listener_index);
 	  if (ll->transport_listener_index != ~0)
 	    {
@@ -445,7 +445,7 @@ mq_send_session_accepted_cb (stream_session_t * s)
   memset (evt, 0, sizeof (*evt));
   evt->event_type = SESSION_CTRL_EVT_ACCEPTED;
   mp = (session_accepted_msg_t *) evt->data;
-  mp->context = app_wrk->wrk_index;
+  mp->context = app->app_index;
   mp->server_rx_fifo = pointer_to_uword (s->server_rx_fifo);
   mp->server_tx_fifo = pointer_to_uword (s->server_tx_fifo);
 
@@ -489,9 +489,7 @@ mq_send_session_accepted_cb (stream_session_t * s)
 	}
       else
 	{
-	  ll =
-	    application_get_local_listen_session (app_wrk,
-						  ls->listener_index);
+	  ll = application_get_local_listen_session (app, ls->listener_index);
 	  if (ll->transport_listener_index != ~0)
 	    {
 	      listener = listen_session_get (ll->transport_listener_index);
@@ -687,7 +685,7 @@ mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
   else
     {
       local_session_t *local;
-      local = application_get_local_listen_session_from_handle (handle);
+      local = application_get_local_listener_w_handle (handle);
       mp->lcl_port = local->port;
       mp->lcl_is_ip4 = session_type_is_ip4 (local->session_type);
     }
@@ -1239,6 +1237,7 @@ vl_api_unbind_sock_t_handler (vl_api_unbind_sock_t * mp)
     {
       a->app_index = app->app_index;
       a->handle = mp->handle;
+      a->wrk_map_index = mp->wrk_index;
       if ((error = vnet_unbind (a)))
 	{
 	  rv = clib_error_get_code (error);
@@ -1255,7 +1254,7 @@ vl_api_connect_sock_t_handler (vl_api_connect_sock_t * mp)
 {
   vl_api_connect_session_reply_t *rmp;
   vnet_connect_args_t _a, *a = &_a;
-  application_t *app;
+  application_t *app = 0;
   clib_error_t *error = 0;
   int rv = 0;
 
@@ -1307,6 +1306,12 @@ vl_api_connect_sock_t_handler (vl_api_connect_sock_t * mp)
 
 done:
   REPLY_MACRO (VL_API_CONNECT_SESSION_REPLY);
+
+  if (app && application_use_mq_for_ctrl (app))
+    {
+      app_worker_t *app_wrk = application_get_worker (app, mp->wrk_index);
+      mq_send_session_connected_cb (app_wrk->wrk_index, mp->context, 0, 1);
+    }
 }
 
 static void
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index 2c425abeaf3..119cdd812ad 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -43,10 +43,19 @@ session_mq_accepted_reply_handler (void *data)
 
   if (session_handle_is_local (mp->handle))
     {
+      app_worker_t *app_wrk;
+      application_t *app;
       ls = application_get_local_session_from_handle (mp->handle);
-      if (!ls || ls->app_wrk_index != mp->context)
+      if (!ls)
 	{
-	  clib_warning ("server %u doesn't own local handle %llu",
+	  clib_warning ("unknown local handle 0x%lx", mp->handle);
+	  return;
+	}
+      app_wrk = app_worker_get (ls->app_wrk_index);
+      app = application_get (app_wrk->app_index);
+      if (app->app_index != mp->context)
+	{
+	  clib_warning ("server %u doesn't own local handle 0x%lx",
 			mp->context, mp->handle);
 	  return;
 	}
@@ -72,7 +81,7 @@ session_mq_accepted_reply_handler (void *data)
 	{
 	  app_worker_t *app;
 	  app = app_worker_get (s->app_wrk_index);
-	  application_send_event (app, s, FIFO_EVENT_APP_RX);
+	  app_worker_send_event (app, s, FIFO_EVENT_APP_RX);
 	}
     }
 }
@@ -726,7 +735,7 @@ session_tx_fifo_dequeue_internal (vlib_main_t * vm,
 				  stream_session_t * s, int *n_tx_pkts)
 {
   application_t *app;
-  app = application_get (s->opaque);
+  app = application_get (s->t_app_index);
   svm_fifo_unset_event (s->server_tx_fifo);
   return app->cb_fns.builtin_app_tx_callback (s);
 }
diff --git a/src/vnet/session/session_test.c b/src/vnet/session/session_test.c
index 6f162a81509..058644d91d4 100644
--- a/src/vnet/session/session_test.c
+++ b/src/vnet/session/session_test.c
@@ -262,7 +262,7 @@ session_test_namespace (vlib_main_t * vm, unformat_input_t * input)
   };
 
   ip4_address_t intf_addr = {
-    .as_u32 = clib_host_to_net_u32 (0x06000105),
+    .as_u32 = clib_host_to_net_u32 (0x07000105),
   };
 
   intf_sep.ip.ip4 = intf_addr;
@@ -1376,7 +1376,7 @@ session_test_proxy (vlib_main_t * vm, unformat_input_t * input)
   char *show_listeners = "sh session listeners tcp verbose";
   char *show_local_listeners = "sh app ns table default";
   unformat_input_t tmp_input;
-  u32 server_index, app_index, server_wrk_index;
+  u32 server_index, app_index;
   u32 dummy_server_api_index = ~0, sw_if_index = 0;
   clib_error_t *error = 0;
   u8 is_filtered = 0;
@@ -1384,7 +1384,6 @@ session_test_proxy (vlib_main_t * vm, unformat_input_t * input)
   transport_connection_t *tc;
   u16 lcl_port = 1234, rmt_port = 4321;
   app_namespace_t *app_ns;
-  application_t *server;
   int verbose = 0;
 
   while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
@@ -1444,8 +1443,6 @@ session_test_proxy (vlib_main_t * vm, unformat_input_t * input)
   error = vnet_application_attach (&attach_args);
   SESSION_TEST ((error == 0), "server attachment should work");
   server_index = attach_args.app_index;
-  server = application_get (server_index);
-  server_wrk_index = application_get_default_worker (server)->wrk_index;
 
   if (verbose)
     {
@@ -1462,7 +1459,7 @@ session_test_proxy (vlib_main_t * vm, unformat_input_t * input)
   SESSION_TEST ((tc != 0), "lookup 1.2.3.4 1234 5.6.7.8 4321 should be "
 		"successful");
   s = listen_session_get (tc->s_index);
-  SESSION_TEST ((s->app_wrk_index == server_wrk_index), "lookup should return"
+  SESSION_TEST ((s->app_index == server_index), "lookup should return"
 		" the server");
 
   tc = session_lookup_connection_wt4 (0, &rmt_ip, &rmt_ip, lcl_port, rmt_port,
diff --git a/src/vnet/session/stream_session.h b/src/vnet/session/stream_session.h
index 567962a35db..b08f9592510 100644
--- a/src/vnet/session/stream_session.h
+++ b/src/vnet/session/stream_session.h
@@ -60,7 +60,7 @@ typedef struct _stream_session_t
   /** Session index in per_thread pool */
   u32 session_index;
 
-  /** app worker pool index */
+  /** App worker pool index */
   u32 app_wrk_index;
 
   u8 thread_index;
@@ -78,6 +78,19 @@ typedef struct _stream_session_t
   {
     /** Parent listener session if the result of an accept */
     u32 listener_index;
+
+    /** Application index if a listener */
+    u32 app_index;
+  };
+
+  union
+  {
+    /** Transport app index for apps acting as transports */
+    u32 t_app_index;
+
+    /** Index in listener app's listener db */
+    u32 listener_db_index;
+
     /** Opaque, for general use */
     u32 opaque;
   };
@@ -103,17 +116,25 @@ typedef struct local_session_
   /** Server index */
   u32 app_wrk_index;
 
+  /** Port for connection. Overlaps thread_index/enqueue_epoch */
+  u16 port;
+
   /** Segment index where fifos were allocated */
   u32 svm_segment_index;
 
-  u32 listener_index;
+  /** Transport listener index. Overlaps connection index */
+  u32 transport_listener_index;
 
-  /** Port for connection */
-  u16 port;
+  union
+  {
+    u32 listener_index;
+    u32 app_index;
+  };
+
+  u32 listener_db_index;
 
   /** Has transport embedded when listener not purely local */
   session_type_t listener_session_type;
-  u32 transport_listener_index;
 
   /**
    * Client data
diff --git a/src/vnet/tls/tls.c b/src/vnet/tls/tls.c
index 4fb0dfb3c91..ae426fba594 100644
--- a/src/vnet/tls/tls.c
+++ b/src/vnet/tls/tls.c
@@ -49,7 +49,7 @@ tls_add_vpp_q_evt (svm_fifo_t * f, u8 evt_type)
 static inline int
 tls_add_app_q_evt (app_worker_t * app, stream_session_t * app_session)
 {
-  return application_send_event (app, app_session, FIFO_EVENT_APP_RX);
+  return app_worker_send_event (app, app_session, FIFO_EVENT_APP_RX);
 }
 
 u32
@@ -168,7 +168,7 @@ tls_notify_app_accept (tls_ctx_t * ctx)
   app_session->session_type = app_listener->session_type;
   app_session->listener_index = app_listener->session_index;
   sm = app_worker_get_listen_segment_manager (app_wrk, app_listener);
-  app_session->opaque = tls_main.app_index;
+  app_session->t_app_index = tls_main.app_index;
 
   if ((rv = session_alloc_fifos (sm, app_session)))
     {
@@ -202,7 +202,7 @@ tls_notify_app_connected (tls_ctx_t * ctx, u8 is_failed)
   app_session->connection_index = ctx->tls_ctx_handle;
   app_session->session_type =
     session_type_from_proto_and_ip (TRANSPORT_PROTO_TLS, ctx->tcp_is_ip4);
-  app_session->opaque = tls_main.app_index;
+  app_session->t_app_index = tls_main.app_index;
 
   if (session_alloc_fifos (sm, app_session))
     goto failed;
@@ -522,7 +522,7 @@ tls_disconnect (u32 ctx_handle, u32 thread_index)
 u32
 tls_start_listen (u32 app_listener_index, transport_endpoint_t * tep)
 {
-  app_worker_t *tls_app_wrk, *app_wrk;
+  app_worker_t *app_wrk;
   tls_main_t *tm = &tls_main;
   session_handle_t tls_handle;
   session_endpoint_extended_t *sep;
@@ -547,10 +547,9 @@ tls_start_listen (u32 app_listener_index, transport_endpoint_t * tep)
 
   /* TODO hide this by calling vnet_bind() */
   tls_app = application_get (tm->app_index);
-  tls_app_wrk = application_get_default_worker (tls_app);
+//  tls_app_wrk = application_get_default_worker (tls_app);
   sep->transport_proto = TRANSPORT_PROTO_TCP;
-  if (app_worker_start_listen (tls_app_wrk, (session_endpoint_t *) sep,
-			       &tls_handle))
+  if (application_start_listen (tls_app, sep, &tls_handle))
     return ~0;
 
   tls_listener = listen_session_get_from_handle (tls_handle);
@@ -580,7 +579,8 @@ tls_stop_listen (u32 lctx_index)
   tls_engine_type_t engine_type;
 
   lctx = tls_listener_ctx_get (lctx_index);
-  app_worker_stop_listen (lctx->tls_session_handle, tm->app_index);
+  /* TODO use unbind */
+  application_stop_listen (tm->app_index, 0, lctx->tls_session_handle);
   engine_type = lctx->tls_ctx_engine;
   tls_vfts[engine_type].ctx_stop_listen (lctx);