diff --git a/tests/system-common-macros.at b/tests/system-common-macros.at
index 64bf5ec63ab4..7b841250c383 100644
--- a/tests/system-common-macros.at
+++ b/tests/system-common-macros.at
@@ -329,3 +329,16 @@ m4_define([OVS_CHECK_IPROUTE_ENCAP],
 # OVS_CHECK_CT_CLEAR()
 m4_define([OVS_CHECK_CT_CLEAR],
     [AT_SKIP_IF([! grep -q "Datapath supports ct_clear action" ovs-vswitchd.log])])
+
+# GEN_ICMP_DATA([start], [len])
+#
+# Generate space-separated ICMP data that is acceptable to tests/sendpkt.py.
+m4_define([GEN_ICMP_DATA],
+    [[
+      ICMP_DATA=""
+      for (( n=0; n<$2; n++ )); do
+          ICMP_DATA="${ICMP_DATA} $(printf %x $((($1+n) % 256)))"
+      done
+      echo "$ICMP_DATA"
+    ]]
+)
diff --git a/tests/system-traffic.at b/tests/system-traffic.at
index 519b234bb16b..37421ed1e78a 100644
--- a/tests/system-traffic.at
+++ b/tests/system-traffic.at
@@ -339,6 +339,73 @@ NS_CHECK_EXEC([at_ns0], [ping -s 3200 -q -c 3 -i 0.3 -w 2 10.1.1.100 | FORMAT_PI
 OVS_TRAFFIC_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([datapath - ping over gre tunnel by simulated packets])
+OVS_CHECK_GRE()
+
+OVS_TRAFFIC_VSWITCHD_START()
+AT_CHECK([ovs-vsctl -- set bridge br0 other-config:hwaddr=\"f2:ff:00:00:00:01\"])
+ADD_BR([br-underlay], [set bridge br-underlay other-config:hwaddr=\"f2:ff:00:00:00:02\"])
+
+AT_CHECK([ovs-ofctl add-flow br0 "actions=normal"])
+AT_CHECK([ovs-ofctl add-flow br-underlay "actions=normal"])
+
+ADD_NAMESPACES(at_ns0)
+
+dnl Set up underlay link from host into the namespace using veth pair.
+ADD_VETH(p0, at_ns0, br-underlay, "172.31.1.1/24", f2:ff:00:00:00:03)
+AT_CHECK([ip addr add dev br-underlay "172.31.1.100/24"])
+AT_CHECK([ip link set dev br-underlay up])
+
+dnl Set up tunnel endpoints on OVS outside the namespace.
+ADD_OVS_TUNNEL([gre], [br0], [at_gre0], [172.31.1.1], [10.1.1.100/24])
+
+ip netns exec at_ns0 tcpdump -U -i p0 -w p0.pcap &
+
+dnl First, check the underlay.
+NS_CHECK_EXEC([at_ns0], [ping -q -c 3 -i 0.3 -w 2 172.31.1.100 | FORMAT_PING], [0], [dnl
+3 packets transmitted, 3 received, 0% packet loss, time 0ms
+])
+
+dnl Okay, now we don't actually add the port as below, instead, we
+dnl emulate it. Suppose its mac address is f2:ff:00:00:00:04.
+dnl ADD_NATIVE_TUNNEL([gretap], [ns_gre0], [at_ns0], [172.31.1.100], [10.1.1.1/24])
+
+dnl Okay, now send out an arp request from 10.1.1.1 for 10.1.1.100 in gre.
+NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 03 08 00 45 00 00 42 ec 2c 40 00 40 2f f3 bc ac 1f 01 01 ac 1f 01 64 00 00 65 58 ff ff ff ff ff ff f2 ff 00 00 00 04 08 06 00 01 08 00 06 04 00 01 f2 ff 00 00 00 04 0a 01 01 01 00 00 00 00 00 00 0a 01 01 64 > /dev/null])
+
+sleep 1
+AT_CHECK([tcpdump -xx -r p0.pcap 2>&1 | egrep "IP 172.31.1.100 > 172.31.1.1: GREv0, length 46: ARP, Reply 10.1.1.100 is-at f2:ff:00:00:00:01 .* length 28" 2>&1 1>/dev/null])
+
+dnl Oaky, now check the overlay by sending out raw icmp packets of
+dnl different sizes in gre protocol.
+
+dnl First, send the packet that emulates
+dnl `ip netns exec at_ns0 ping 10.1.1.100`
+NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 03 08 00 45 00 00 7a ec 8e 40 00 40 2f f3 22 ac 1f 01 01 ac 1f 01 64 00 00 65 58 f2 ff 00 00 00 01 f2 ff 00 00 00 04 08 00 45 00 00 54 54 8f 40 00 40 01 cf b3 0a 01 01 01 0a 01 01 64 08 00 e6 e8 29 27 00 03 e1 a3 43 5b 00 00 00 00 ff 1a 05 00 00 00 00 00 $(GEN_ICMP_DATA(16, 40)) > /dev/null])
+
+sleep 1
+AT_CHECK([tcpdump -xx -r p0.pcap 2>&1 | egrep "IP 172.31.1.100 > 172.31.1.1: GREv0, length 102: IP 10.1.1.100 > 10.1.1.1: ICMP echo reply, .* length 64$" 2>&1 1>/dev/null])
+
+dnl Second, send the packet that emulates
+dnl `ip netns exec at_ns0 ping -s 1600 10.1.1.100`
+NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 03 08 00 45 00 05 ca 9a 7b 40 00 40 2f 3f e6 ac 1f 01 01 ac 1f 01 64 00 00 65 58 f2 ff 00 00 00 01 f2 ff 00 00 00 04 08 00 45 00 05 a4 6d 4d 20 00 40 01 d1 a5 0a 01 01 01 0a 01 01 64 08 00 11 cc 13 ed 00 01 82 c6 43 5b 00 00 00 00 d2 e1 0c 00 00 00 00 00 $(GEN_ICMP_DATA(16, 1400)) > /dev/null])
+NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 03 08 00 45 00 00 f2 9a 7c 40 00 40 2f 44 bd ac 1f 01 01 ac 1f 01 64 00 00 65 58 f2 ff 00 00 00 01 f2 ff 00 00 00 04 08 00 45 00 00 cc 6d 4d 00 b2 40 01 f5 cb 0a 01 01 01 0a 01 01 64 $(GEN_ICMP_DATA(136, 184)) > /dev/null])
+
+sleep 1
+AT_CHECK([tcpdump -xx -r p0.pcap 2>&1 | egrep "IP 172.31.1.100 > 172.31.1.1: GREv0, length 222: IP 10.1.1.100 > 10.1.1.1: icmp" 2>&1 1>/dev/null])
+
+dnl Lastly, send the packet that emulates
+dnl `ip netns exec at_ns0 ping -s 3200 10.1.1.100`
+NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 03 08 00 45 00 05 ca 9b 5e 40 00 40 2f 3f 03 ac 1f 01 01 ac 1f 01 64 00 00 65 58 f2 ff 00 00 00 01 f2 ff 00 00 00 04 08 00 45 00 05 a4 6d af 20 00 40 01 d1 43 0a 01 01 01 0a 01 01 64 08 00 55 ce 13 f4 00 03 84 c6 43 5b 00 00 00 00 29 4c 02 00 00 00 00 00 $(GEN_ICMP_DATA(16, 1400)) > /dev/null])
+NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 03 08 00 45 00 05 ca 9b 5f 40 00 40 2f 3f 02 ac 1f 01 01 ac 1f 01 64 00 00 65 58 f2 ff 00 00 00 01 f2 ff 00 00 00 04 08 00 45 00 05 a4 6d af 20 b2 40 01 d0 91 0a 01 01 01 0a 01 01 64 $(GEN_ICMP_DATA(136, 1424)) > /dev/null])
+NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 03 08 00 45 00 01 a2 9b 60 40 00 40 2f 43 29 ac 1f 01 01 ac 1f 01 64 00 00 65 58 f2 ff 00 00 00 01 f2 ff 00 00 00 04 08 00 45 00 01 7c 6d af 01 64 40 01 f4 07 0a 01 01 01 0a 01 01 64 $(GEN_ICMP_DATA(24, 360)) > /dev/null])
+
+sleep 1
+AT_CHECK([tcpdump -xx -r p0.pcap 2>&1 | egrep "IP 172.31.1.100 > 172.31.1.1: GREv0, length 398: IP 10.1.1.100 > 10.1.1.1: icmp" 2>&1 1>/dev/null])
+
+OVS_TRAFFIC_VSWITCHD_STOP
+AT_CLEANUP
+
 AT_SETUP([datapath - ping over erspan v1 tunnel])
 OVS_CHECK_GRE()
 OVS_CHECK_ERSPAN()
