diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index d4dfeec..56d034e 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -407,7 +407,7 @@
  * @return		0 if success, negative integer otherwise
  */
 static inline int
-app_send_io_evt_to_vpp (svm_msg_q_t * mq, svm_fifo_t * f, u8 evt_type,
+app_send_io_evt_to_vpp (svm_msg_q_t * mq, u32 session_index, u8 evt_type,
 			u8 noblock)
 {
   session_event_t *evt;
@@ -429,7 +429,7 @@
 	  return -2;
 	}
       evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-      evt->fifo = f;
+      evt->session_index = session_index;
       evt->event_type = evt_type;
       svm_msg_q_add_and_unlock (mq, &msg);
       return 0;
@@ -441,7 +441,7 @@
 	svm_msg_q_wait (mq);
       msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
       evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-      evt->fifo = f;
+      evt->session_index = session_index;
       evt->event_type = evt_type;
       if (svm_msg_q_is_full (mq))
 	svm_msg_q_wait (mq);
@@ -478,7 +478,8 @@
   if ((rv = svm_fifo_enqueue_nowait (f, actual_write, data)) > 0)
     {
       if (do_evt && svm_fifo_set_event (f))
-	app_send_io_evt_to_vpp (vpp_evt_q, f, evt_type, noblock);
+	app_send_io_evt_to_vpp (vpp_evt_q, f->master_session_index, evt_type,
+				noblock);
     }
   ASSERT (rv);
   return rv;
@@ -501,7 +502,8 @@
   if ((rv = svm_fifo_enqueue_nowait (f, len, data)) > 0)
     {
       if (do_evt && svm_fifo_set_event (f))
-	app_send_io_evt_to_vpp (vpp_evt_q, f, evt_type, noblock);
+	app_send_io_evt_to_vpp (vpp_evt_q, f->master_session_index, evt_type,
+				noblock);
     }
   return rv;
 }
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index 7c88888..85a6fed 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -562,7 +562,7 @@
   ASSERT (!svm_msg_q_msg_is_invalid (&msg));
 
   evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-  evt->fifo = s->rx_fifo;
+  evt->session_index = s->rx_fifo->client_session_index;
   evt->event_type = SESSION_IO_EVT_RX;
 
   (void) svm_fifo_set_event (s->rx_fifo);
@@ -599,7 +599,7 @@
 
   evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
   evt->event_type = SESSION_IO_EVT_TX;
-  evt->fifo = s->tx_fifo;
+  evt->session_index = s->tx_fifo->client_session_index;
 
   return app_enqueue_evt (mq, &msg, lock);
 }
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index 6e24d56..0a294dc 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -66,7 +66,7 @@
     case SESSION_IO_EVT_TX:
     case SESSION_IO_EVT_TX_FLUSH:
     case SESSION_IO_EVT_BUILTIN_RX:
-      evt->fifo = data;
+      evt->session_index = *(u32 *) data;
       break;
     case SESSION_IO_EVT_BUILTIN_TX:
     case SESSION_CTRL_EVT_CLOSE:
@@ -85,7 +85,8 @@
 int
 session_send_io_evt_to_thread (svm_fifo_t * f, session_evt_type_t evt_type)
 {
-  return session_send_evt_to_thread (f, 0, f->master_thread_index, evt_type);
+  return session_send_evt_to_thread (&f->master_session_index, 0,
+				     f->master_thread_index, evt_type);
 }
 
 int
@@ -560,7 +561,7 @@
 	  continue;
 	}
 
-      if (svm_fifo_is_empty (s->rx_fifo))
+      if (svm_fifo_has_event (s->rx_fifo) || svm_fifo_is_empty (s->rx_fifo))
 	continue;
 
       if (PREDICT_FALSE (session_enqueue_notify_inline (s)))
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index db5123b..7cbd0d9 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -821,7 +821,7 @@
   session_t *s = wrk->ctx.s;
   application_t *app;
 
-  if (PREDICT_FALSE (s->session_state == SESSION_STATE_CLOSED))
+  if (PREDICT_FALSE (s->session_state >= SESSION_STATE_TRANSPORT_CLOSED))
     return 0;
   app = application_get (s->t_app_index);
   svm_fifo_unset_event (s->tx_fifo);
@@ -831,7 +831,7 @@
 always_inline session_t *
 session_event_get_session (session_event_t * e, u8 thread_index)
 {
-  return session_get_if_valid (e->fifo->master_session_index, thread_index);
+  return session_get_if_valid (e->session_index, thread_index);
 }
 
 static void
@@ -1103,7 +1103,7 @@
     case SESSION_IO_EVT_RX:
     case SESSION_IO_EVT_TX:
     case SESSION_IO_EVT_BUILTIN_RX:
-      if (e->fifo == f)
+      if (e->session_index == f->master_session_index)
 	return 1;
       break;
     case SESSION_CTRL_EVT_CLOSE:
diff --git a/src/vnet/session/session_types.h b/src/vnet/session/session_types.h
index 9e51d69..3b6ab3d 100644
--- a/src/vnet/session/session_types.h
+++ b/src/vnet/session/session_types.h
@@ -326,7 +326,7 @@
   u8 postponed;
   union
   {
-    svm_fifo_t *fifo;
+    u32 session_index;
     session_handle_t session_handle;
     session_rpc_args_t rpc_args;
     struct