diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index f503500..95480af 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1749,7 +1749,7 @@
       && tc->rxt_head != tc->snd_una
       && tcp_retransmit_should_retry_head (tc, sb))
     {
-      max_bytes = clib_min (tc->snd_mss, tc->snd_congestion - tc->snd_una);
+      max_bytes = clib_min (tc->snd_mss, tc->snd_nxt - tc->snd_una);
       n_written = tcp_prepare_retransmit_segment (wrk, tc, 0, max_bytes, &b);
       if (!n_written)
 	{