diff --git a/tests/system-traffic.at b/tests/system-traffic.at
index 8ea450887076..ba8e3776ccd4 100644
--- a/tests/system-traffic.at
+++ b/tests/system-traffic.at
@@ -5871,8 +5871,7 @@ dnl The flow will encap a nsh header to the TCP syn packet
 dnl eth/ip/tcp --> OVS --> eth/nsh/eth/ip/tcp
 AT_CHECK([ovs-ofctl -Oopenflow13 add-flow br0 "table=0,priority=100,in_port=ovs-p0,ip,actions=encap(nsh(md_type=1)),set_field:0x1234->nsh_spi,set_field:0x11223344->nsh_c1,encap(ethernet),set_field:f2:ff:00:00:00:02->dl_dst,set_field:f2:ff:00:00:00:01->dl_src,ovs-p1"])
 
-rm ovs-p1.pcap
-tcpdump -U -i ovs-p1 -w ovs-p1.pcap &
+AT_CHECK([tcpdump -n -xx -U -i ovs-p1 > ovs-p1.pcap &])
 sleep 1
 
 dnl The hex dump is a TCP syn packet. pkt=eth/ip/tcp
@@ -5880,20 +5879,18 @@ dnl The packet is sent from p0(at_ns0) interface directed to
 dnl p1(at_ns1) interface
 NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 00 00 00 00 02 f2 00 00 00 00 01 08 00 45 00 00 28 00 01 00 00 40 06 b0 13 c0 a8 00 0a 0a 00 00 0a 04 00 08 00 00 00 00 c8 00 00 00 00 50 02 20 00 b8 5e 00 00 > /dev/null])
 
-sleep 1
-
 dnl Check the expected nsh encapsulated packet on the egress interface
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000 *0001 *894f *0fc6" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0010: *0103 *0012 *34ff *1122 *3344 *0000 *0000 *0000" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0020: *0000 *0000 *0000 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
-
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000 *0001 *894f *0fc6" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0010: *0103 *0012 *34ff *1122 *3344 *0000 *0000 *0000" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0020: *0000 *0000 *0000 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
 
 OVS_TRAFFIC_VSWITCHD_STOP
 AT_CLEANUP
 
+
 AT_SETUP([nsh - decap header])
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -5906,8 +5903,7 @@ dnl The flow will decap a nsh header which in turn carries a TCP syn packet
 dnl eth/nsh/eth/ip/tcp --> OVS --> eth/ip/tcp
 AT_CHECK([ovs-ofctl -Oopenflow13 add-flow br0 "table=0,priority=100,in_port=ovs-p0,dl_type=0x894f, actions=decap(),decap(), ovs-p1"])
 
-rm ovs-p1.pcap
-tcpdump -U -i ovs-p1 -w ovs-p1.pcap &
+AT_CHECK([tcpdump -n -xx -U -i ovs-p1 > ovs-p1.pcap &])
 sleep 1
 
 dnl The hex dump is NSH packet with TCP syn payload. pkt=eth/nsh/eth/ip/tcp
@@ -5915,18 +5911,16 @@ dnl The packet is sent from p0(at_ns0) interface directed to
 dnl p1(at_ns1) interface
 NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 01 89 4f 02 06 01 03 00 00 64 03 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 f2 00 00 00 00 02 f2 00 00 00 00 01 08 00 45 00 00 28 00 01 00 00 40 06 b0 13 c0 a8 00 0a 0a 00 00 0a 04 00 08 00 00 00 00 c8 00 00 00 00 50 02 20 00 b8 5e 00 00 > /dev/null])
 
-sleep 1
-
 dnl Check the expected de-capsulated TCP packet on the egress interface
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0000: *f200 *0000 *0002 *f200 *0000 *0001 *0800 *4500" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0010: *0028 *0001 *0000 *4006 *b013 *c0a8 *000a *0a00" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0020: *000a *0400 *0800 *0000 *00c8 *0000 *0000 *5002" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0030: *2000 *b85e *0000" 2>&1 1>/dev/null])
-
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0000: *f200 *0000 *0002 *f200 *0000 *0001 *0800 *4500" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0010: *0028 *0001 *0000 *4006 *b013 *c0a8 *000a *0a00" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0020: *000a *0400 *0800 *0000 *00c8 *0000 *0000 *5002" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0030: *2000 *b85e *0000" 2>&1 1>/dev/null])
 
 OVS_TRAFFIC_VSWITCHD_STOP
 AT_CLEANUP
 
+
 AT_SETUP([nsh - replace header])
 OVS_TRAFFIC_VSWITCHD_START()
 
@@ -5941,8 +5935,7 @@ dnl The flow will add another NSH header with nsh_spi=0x101, nsh_si=4,
 dnl nsh_ttl=7 and change the md1 context
 AT_CHECK([ovs-ofctl -Oopenflow13 add-flow br0 "table=0,priority=100,in_port=ovs-p0,dl_type=0x894f,nsh_spi=0x100,nsh_si=0x03,actions=decap(),decap(),encap(nsh(md_type=1)),set_field:0x07->nsh_ttl,set_field:0x0101->nsh_spi,set_field:0x04->nsh_si,set_field:0x100f0e0d->nsh_c1,set_field:0x0c0b0a09->nsh_c2,set_field:0x08070605->nsh_c3,set_field:0x04030201->nsh_c4,encap(ethernet),set_field:f2:ff:00:00:00:02->dl_dst,set_field:f2:ff:00:00:00:01->dl_src,ovs-p1"])
 
-rm ovs-p1.pcap
-tcpdump -U -i ovs-p1 -w ovs-p1.pcap &
+AT_CHECK([tcpdump -n -xx -U -i ovs-p1 > ovs-p1.pcap &])
 sleep 1
 
 dnl The hex dump is NSH packet with TCP syn payload. pkt=eth/nsh/eth/ip/tcp
@@ -5951,15 +5944,13 @@ dnl The packet is sent from p0(at_ns0) interface directed to
 dnl p1(at_ns1) interface
 NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 01 89 4f 02 06 01 03 00 01 00 03 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 f2 00 00 00 00 02 f2 00 00 00 00 01 08 00 45 00 00 28 00 01 00 00 40 06 b0 13 c0 a8 00 0a 0a 00 00 0a 04 00 08 00 00 00 00 c8 00 00 00 00 50 02 20 00 b8 5e 00 00 > /dev/null])
 
-sleep 1
-
 dnl Check the expected NSH packet with new fields in the header
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000* 0001 *894f *01c6" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0010: *0103 *0001 *0104 *100f *0e0d *0c0b *0a09 *0807" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0020: *0605 *0403 *0201 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000* 0001 *894f *01c6" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0010: *0103 *0001 *0104 *100f *0e0d *0c0b *0a09 *0807" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0020: *0605 *0403 *0201 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
 
 OVS_TRAFFIC_VSWITCHD_STOP
 AT_CLEANUP
@@ -5980,41 +5971,31 @@ dnl packet to to at_ns2.
 AT_CHECK([ovs-ofctl -Oopenflow13 add-flow br0 "table=0,priority=100,dl_type=0x894f,nsh_spi=0x100,nsh_si=0x02,actions=ovs-p1"])
 AT_CHECK([ovs-ofctl -Oopenflow13 add-flow br0 "table=0,priority=100,dl_type=0x894f,nsh_spi=0x100,nsh_si=0x01,actions=ovs-p2"])
 
-
-rm ovs-p1.pcap
-rm ovs-p2.pcap
-tcpdump -U -i ovs-p1 -w ovs-p1.pcap &
-tcpdump -U -i ovs-p2 -w ovs-p2.pcap &
+AT_CHECK([tcpdump -n -xx -U -i ovs-p1 > ovs-p1.pcap &])
+AT_CHECK([tcpdump -n -xx -U -i ovs-p2 > ovs-p2.pcap &])
 sleep 1
 
 dnl First send packet from at_ns0 --> OVS with SPI=0x100 and SI=2
 NS_CHECK_EXEC([at_ns0], [$PYTHON $srcdir/sendpkt.py p0 f2 ff 00 00 00 02 f2 ff 00 00 00 01 89 4f 02 06 01 03 00 01 00 02 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 f2 00 00 00 00 02 f2 00 00 00 00 01 08 00 45 00 00 28 00 01 00 00 40 06 b0 13 c0 a8 00 0a 0a 00 00 0a 04 00 08 00 00 00 00 c8 00 00 00 00 50 02 20 00 b8 5e 00 00 > /dev/null])
 
-sleep 1
-
 dnl Check for the above packet on ovs-p1 interface
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000 *0001 *894f *0206" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0010: *0103 *0001 *0002 *0102 *0304 *0506 *0708 *090a" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0020: *0b0c *0d0e *0f10 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p1.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
-
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000 *0001 *894f *0206" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0010: *0103 *0001 *0002 *0102 *0304 *0506 *0708 *090a" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0020: *0b0c *0d0e *0f10 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p1.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
 
 dnl Send the second packet from at_ns1 --> OVS with SPI=0x100 and SI=1
 NS_CHECK_EXEC([at_ns1], [$PYTHON $srcdir/sendpkt.py p1 f2 ff 00 00 00 02 f2 ff 00 00 00 01 89 4f 01 c6 01 03 00 01 00 01 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 f2 00 00 00 00 02 f2 00 00 00 00 01 08 00 45 00 00 28 00 01 00 00 40 06 b0 13 c0 a8 00 0a 0a 00 00 0a 04 00 08 00 00 00 00 c8 00 00 00 00 50 02 20 00 b8 5e 00 00 > /dev/null])
 
-sleep 1
-
 dnl Check for the above packet on ovs-p2 interface
-AT_CHECK([tcpdump -xx -r ovs-p2.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000 *0001 *894f *01c6" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p2.pcap 2>&1 | egrep "0x0010: *0103 *0001 *0001 *0102 *0304 *0506 *0708 *090a" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p2.pcap 2>&1 | egrep "0x0020: *0b0c *0d0e *0f10 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p2.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p2.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
-AT_CHECK([tcpdump -xx -r ovs-p2.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
-
-
+OVS_WAIT_UNTIL([cat ovs-p2.pcap 2>&1 | egrep "0x0000: *f2ff *0000 *0002 *f2ff *0000 *0001 *894f *01c6" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p2.pcap 2>&1 | egrep "0x0010: *0103 *0001 *0001 *0102 *0304 *0506 *0708 *090a" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p2.pcap 2>&1 | egrep "0x0020: *0b0c *0d0e *0f10 *f200 *0000 *0002 *f200 *0000" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p2.pcap 2>&1 | egrep "0x0030: *0001 *0800 *4500 *0028 *0001 *0000 *4006 *b013" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p2.pcap 2>&1 | egrep "0x0040: *c0a8 *000a *0a00 *000a *0400 *0800 *0000 *00c8" 2>&1 1>/dev/null])
+OVS_WAIT_UNTIL([cat ovs-p2.pcap 2>&1 | egrep "0x0050: *0000 *0000 *5002 *2000 *b85e *0000" 2>&1 1>/dev/null])
 
 OVS_TRAFFIC_VSWITCHD_STOP
 AT_CLEANUP
