diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index 7309e0a..4b0a0dd 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -435,6 +435,7 @@
   u32 last_fib_check;	/**< Last time we checked fib route for peer */
   u16 mss;		/**< Our max seg size that includes options */
   u32 timestamp_delta;	/**< Offset for timestamp */
+  u32 ipv6_flow_label;	/**< flow label for ipv6 header */
 } tcp_connection_t;
 
 /* *INDENT-OFF* */
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 71e9d7b..c7e9792 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -842,8 +842,10 @@
       int bogus = ~0;
       ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) ==
 	      0x60);
-      ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address,
-				  &pkt_ih6->src_address, IP_PROTOCOL_TCP);
+      ih6 = vlib_buffer_push_ip6_custom (vm, b, &pkt_ih6->dst_address,
+					 &pkt_ih6->src_address,
+					 IP_PROTOCOL_TCP,
+					 tc->ipv6_flow_label);
       th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus);
       ASSERT (!bogus);
     }
@@ -909,8 +911,9 @@
       ip6_header_t *ih;
       int bogus = ~0;
 
-      ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6,
-				 &tc->c_rmt_ip6, IP_PROTOCOL_TCP);
+      ih = vlib_buffer_push_ip6_custom (vm, b, &tc->c_lcl_ip6,
+					&tc->c_rmt_ip6, IP_PROTOCOL_TCP,
+					tc->ipv6_flow_label);
       th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus);
       ASSERT (!bogus);
     }
@@ -2278,8 +2281,9 @@
     ih0 = vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4,
 				IP_PROTOCOL_TCP, tcp_csum_offload (tc0));
   else
-    ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6, &tc0->c_rmt_ip6,
-				IP_PROTOCOL_TCP);
+    ih0 =
+      vlib_buffer_push_ip6_custom (vm, b0, &tc0->c_lcl_ip6, &tc0->c_rmt_ip6,
+				   IP_PROTOCOL_TCP, tc0->ipv6_flow_label);
 
 }