diff --git a/include/net/tcp.h b/include/net/tcp.h
index b448030..38509f0 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -60,6 +60,9 @@
  */
 #define MAX_TCP_WINDOW		32767U
 
+/* Offer an initial receive window of 10 mss. */
+#define TCP_DEFAULT_INIT_RCVWND	10
+
 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
 #define TCP_MIN_MSS		88U