diff --git a/ChangeLog b/ChangeLog
index 04e17597a0..613c081ed5 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -12084,3 +12084,21 @@
 	  option.  Without this configuration setting, interrupt level output
 	  will be asynchronous.  And (3) vsyslog is now a system call and is
 	  usable with other-than-FLAT builds (2016-06-19).
+	* TCP Networking: While working with version 7.10 I discovered a
+	  problem in TCP stack that could be observed on high network load.
+	  Generally speaking, the problem is that RST flag is set in
+	  unnecessary case, in which between loss of some TCP packet and its
+	  proper retransmission, another packets had been successfully sent.
+	  The scenario is as follows:  NuttX did not receive ACK for some
+	  sent packet, so it has been probably lost somewhere. But before
+	  its retransmission starts, NuttX is correctly issuing next TCP
+	  packets, with sequence numbers increasing properly. When the
+	  retransmission of previously lost packet finally succeeds, tcp_input
+	  receives the accumulated ACK value, which acknowledges also the
+	  packets sent in the meantime (i.e. between unsuccessful sending of
+	  lost packet and its proper retransmission). However, variable unackseq
+	  is still set to conn->isn + conn->sent, which is truth only if no
+	  further packets transmission occurred in the meantime.  Because of
+	  incorrect (in such specific case) unackseq value, few lines further
+	  condition if (ackseq <= unackseq)is not met, and, as a result, we
+	  are going to reset label.  From  Jakub Łągwa (2016-06-20).
diff --git a/net/tcp/tcp.h b/net/tcp/tcp.h
index e95d50cdf4..c53475d75a 100644
--- a/net/tcp/tcp.h
+++ b/net/tcp/tcp.h
@@ -206,6 +206,8 @@ struct tcp_conn_s
                            * it can only be updated at TCP_ESTABLISHED state */
   uint32_t   sent;        /* The number of bytes sent (ACKed and un-ACKed) */
   uint32_t   isn;         /* Initial sequence number */
+  uint32_t   sndseq_max;  /* The sequence number of next not-retransmitted
+                           * segment (next greater sndseq) */
 #endif
 
 #ifdef CONFIG_NET_TCPBACKLOG
@@ -665,7 +667,7 @@ void tcp_poll(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn);
  * Parameters:
  *   dev  - The device driver structure to use in the send operation
  *   conn - The TCP "connection" to poll for TX data
- *   hsed - The polling interval in halves of a second
+ *   hsec - The polling interval in halves of a second
  *
  * Return:
  *   None
diff --git a/net/tcp/tcp_conn.c b/net/tcp/tcp_conn.c
index fa11c42c4a..83ca79f8e4 100644
--- a/net/tcp/tcp_conn.c
+++ b/net/tcp/tcp_conn.c
@@ -1083,11 +1083,12 @@ FAR struct tcp_conn_s *tcp_alloc_accept(FAR struct net_driver_s *dev,
       conn->tcpstateflags = TCP_SYN_RCVD;
 
       tcp_initsequence(conn->sndseq);
-      conn->unacked = 1;
+      conn->unacked       = 1;
 #ifdef CONFIG_NET_TCP_WRITE_BUFFERS
-      conn->expired = 0;
-      conn->isn     = 0;
-      conn->sent    = 0;
+      conn->expired       = 0;
+      conn->isn           = 0;
+      conn->sent          = 0;
+      conn->sndseq_max    = 0;
 #endif
 
       /* rcvseq should be the seqno from the incoming packet + 1. */
@@ -1344,6 +1345,7 @@ int tcp_connect(FAR struct tcp_conn_s *conn, FAR const struct sockaddr *addr)
   conn->expired    = 0;
   conn->isn        = 0;
   conn->sent       = 0;
+  conn->sndseq_max = 0;
 #endif
 
 #ifdef CONFIG_NET_TCP_READAHEAD
diff --git a/net/tcp/tcp_input.c b/net/tcp/tcp_input.c
index 277db67412..3834a5cf47 100644
--- a/net/tcp/tcp_input.c
+++ b/net/tcp/tcp_input.c
@@ -364,7 +364,7 @@ found:
        */
 
 #ifdef CONFIG_NET_TCP_WRITE_BUFFERS
-      unackseq = conn->isn + conn->sent;
+      unackseq = conn->sndseq_max;
 #else
       unackseq = tcp_addsequence(conn->sndseq, conn->unacked);
 #endif
@@ -468,6 +468,7 @@ found:
             conn->isn           = tcp_getsequence(tcp->ackno);
             tcp_setsequence(conn->sndseq, conn->isn);
             conn->sent          = 0;
+            conn->sndseq_max    = 0;
 #endif
             conn->unacked       = 0;
             flags               = TCP_CONNECTED;
diff --git a/net/tcp/tcp_send_buffered.c b/net/tcp/tcp_send_buffered.c
index a343d0d046..9d4068af24 100644
--- a/net/tcp/tcp_send_buffered.c
+++ b/net/tcp/tcp_send_buffered.c
@@ -201,7 +201,8 @@ static inline void psock_lost_connection(FAR struct socket *psock,
 
   sq_init(&conn->unacked_q);
   sq_init(&conn->write_q);
-  conn->sent = 0;
+  conn->sent       = 0;
+  conn->sndseq_max = 0;
 }
 
 /****************************************************************************
@@ -654,7 +655,7 @@ static uint16_t psock_send_interrupt(FAR struct net_driver_s *dev,
             {
               /* Insert the write buffer into the write_q (in sequence
                * number order).  The retransmission will occur below
-               * when the write buffer with the lowest sequenc number
+               * when the write buffer with the lowest sequence number
                * is pulled from the write_q again.
                */
 
@@ -696,6 +697,7 @@ static uint16_t psock_send_interrupt(FAR struct net_driver_s *dev,
       if (psock_send_addrchck(conn))
         {
           FAR struct tcp_wrbuffer_s *wrb;
+          uint32_t predicted_seqno;
           size_t sndlen;
 
           /* Peek at the head of the write queue (but don't remove anything
@@ -770,6 +772,16 @@ static uint16_t psock_send_interrupt(FAR struct net_driver_s *dev,
           conn->unacked += sndlen;
           conn->sent    += sndlen;
 
+          /* Below prediction will become true, unless retransmission occurrence */
+
+          predicted_seqno = tcp_getsequence(conn->sndseq) + sndlen;
+
+          if ((predicted_seqno > conn->sndseq_max) ||
+              (tcp_getsequence(conn->sndseq) > predicted_seqno)) /* overflow */
+            {
+               conn->sndseq_max = predicted_seqno;
+            }
+
           nllinfo("SEND: wrb=%p nrtx=%u unacked=%u sent=%u\n",
                   wrb, WRB_NRTX(wrb), conn->unacked, conn->sent);