For the tap-device, the local vlan tag was stripped before send to it. So you
cannot see it.
And in your last comment #6, you can see, all your packets do not have any vlan
tag.
Here are some example packets which have vlan id 205 captured by tcpdump:
14:53:54.915607 fe:ea:c8:20:fe:d0 > Broadcast, ethertype 802.1Q (0x8100),
length 64: vlan 205, p 0, ethertype ARP, Request who-has xxx.xxx.xxx.xxx tell
xxx.xxx.xxx.xxx, length 46
14:53:55.153421 fe:ea:c8:20:fe:d0 > Broadcast, ethertype 802.1Q (0x8100),
length 64: vlan 205, p 0, ethertype ARP, Request who-has xxx.xxx.xxx.xxx tell
xxx.xxx.xxx.xxx, length 46
And if you checked the OF flows, you may see the following 'strip_vlan'
actions:
dl_vlan=34,dl_dst=fa:16:3e:64:9d:57 actions=strip_vlan,output:2235
dl_vlan=34,dl_dst=fa:16:3e:64:9d:57
actions=load:0x8bb->NXM_NX_REG5[],load:0x22->NXM_NX_REG6[],strip_vlan,resubmit(,81)
ovs-ofctl show br-int|grep tapbad2bb56-13
2235(tapbad2bb56-13): addr:fe:16:3e:64:9d:57
For the "TCP Retransmission", the reason can be varied. I can guess even you do
not restart ovs-agent, you will see the
"TCP Retransmission" if the network is congested
So, I don't think this is an issue.
** Changed in: neutron
Status: New => Invalid
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You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to neutron.
https://bugs.launchpad.net/bugs/1822256
Title:
Ip segments lost when restart ovs-agent with openvswitch firewall
Status in neutron:
Invalid
Bug description:
environment：
linux version: Linux controller.novalocal 3.10.0-693.el7.x86_64 #1 SMP Tue
Aug 22 21:09:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
OpenStack version: Rocky
network type: vxlan or vlan
firewall driver: openvswitch
1. Create 2 VMs(vm1, vm2) in different compute nodes(node-1, node-2)
with all tcp passed sg in one network.
2. Login to vm2, create a large file, for example:
vm2# dd if=/dev/zero of=/mnt/test.img bs=1G count=5
3.Login to vm1, scp vm2's large file into vm1, when scp process starts, go to
step 4.
vm1# scp vm2-ip:/mnt/test.img /mnt
4.Login to node-2, and restart neutron-openvswitch-agent, this will refresh
all the openflow in br-int
node-2# systemctl restart neutron-openvswitch-agent
5.Login to vm1, and after several seconds, you will find the scp
process status is stalled.
After some investigation, I found the openflow refresh causes ip
segments lost.When this happened, I captured packets with "tcpdump -i
tap-xxx -w tmp.pcap", and with wireshark I saw these errors:
192.168.100.19 192.168.100.5 SSH 16478 Server: [TCP ACKed
unseen segment] [TCP Previous segment not captured] , Encrypted packet
(len=16412)
192.168.100.19 192.168.100.5 SSH 8302 Server: [TCP ACKed
unseen segment] , Encrypted packet (len=8236)
192.168.100.5 192.168.100.19 TCP 66 [TCP ACKed unseen segment] [TCP
Previous segment not captured] 54354 → 22 [ACK] Seq=2509 Ack=600733 Win=16522
Len=0 TSval=2847412 TSecr=2851031
192.168.100.19 192.168.100.5 SSH 1464 Server: [TCP Spurious
Retransmission] , Encrypted packet (len=1398)
192.168.100.5 192.168.100.19 TCP 78 [TCP Dup ACK 25182#1] 54354 →
22 [ACK] Seq=326305 Ack=67089901 Win=18494 Len=0 TSval=2849742 TSecr=2853310
SLE=67073429 SRE=67074827
192.168.100.5 192.168.100.19 TCP 110 [TCP Retransmission] 54354 → 22
[PSH, ACK] Seq=326173 Ack=67089901 Win=18494 Len=44 TSval=2849742 TSecr=2853310
192.168.100.19 192.168.100.5 TCP 1464 [TCP Retransmission] 22
→ 54354 [ACK] Seq=70971905 Ack=346105 Win=2016 Len=1398 TSval=2853361
TSecr=2849691
192.168.100.19 192.168.100.5 TCP 1464 [TCP Retransmission] 22
→ 54354 [ACK] Seq=70971905 Ack=346105 Win=2016 Len=1398 TSval=2853463
TSecr=2849691
192.168.100.19 192.168.100.5 TCP 1464 [TCP Retransmission] 22
→ 54354 [ACK] Seq=70971905 Ack=346105 Win=2016 Len=1398 TSval=2854076
TSecr=2849691
And I checked the statue of this tcp connect in both compute nodes, it's
still ESTABLISHED.
# conntrack -L | grep 192.168.100.5
tcp 6 299 ESTABLISHED src=192.168.100.5 dst=192.168.100.19 sport=54356
dport=22 src=192.168.100.19 dst=192.168.100.5 sport=22 dport=54354 [ASSURED]
mark=0 zone=4 use=1
# conntrack -L | grep 192.168.100.5
tcp 6 287 ESTABLISHED src=192.168.100.5 dst=192.168.100.19 sport=54356
dport=22 src=192.168.100.19 dst=192.168.100.5 sport=22 dport=54354 [ASSURED]
mark=0 zone=1 use=1
I have no idea why refresh openflow will cause ip segments lost, hopes
someone has a way to solve this problem.
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