unicast ARP problem

Bug #1510058 reported by Dominik Mostowiec on 2015-10-26
24
This bug affects 4 people
Affects Status Importance Assigned to Milestone
Juniper Openstack
Status tracked in Trunk
R2.20
Incomplete
High
Anand H. Krishnan
R3.0
Incomplete
High
Anand H. Krishnan
R3.1
Incomplete
High
Anand H. Krishnan
Trunk
Incomplete
High
Anand H. Krishnan

Bug Description

On R2.20 we noticed strange unicast ARP behaviour.
2 VMs on separated compute nodes.
VM_SRC: 10.189.85.11(02:86:45:5e:06:38), VM_DST: 10.189.85.10(02:25:6b:67:72:e9)

tcpdump on VM_SRC:
tcpdump -i eth0 -e arp
13:41:41.694854 02:25:6b:67:72:e9 (oui Unknown) > 02:86:45:5e:06:38
(oui Unknown), ethertype ARP (0x0806), length 42: Request who-has
10.189.85.11 tell 10.189.85.10, length 28
13:41:42.696888 02:25:6b:67:72:e9 (oui Unknown) > 02:86:45:5e:06:38
(oui Unknown), ethertype ARP (0x0806), length 42: Request who-has
10.189.85.11 tell 10.189.85.10, length 28
13:41:43.698889 02:25:6b:67:72:e9 (oui Unknown) > 02:86:45:5e:06:38
(oui Unknown), ethertype ARP (0x0806), length 42: Request who-has
10.189.85.11 tell 10.189.85.10, length 28
13:41:45.690163 02:25:6b:67:72:e9 (oui Unknown) > Broadcast, ethertype
ARP (0x0806), length 42: Request who-has 10.189.85.11 tell
10.189.85.10, length 28
13:41:45.690203 02:86:45:5e:06:38 (oui Unknown) > 02:25:6b:67:72:e9
(oui Unknown), ethertype ARP (0x0806), length 42: Reply 10.189.85.11
is-at 02:86:45:5e:06:38 (oui Unknown), length 28

3 x request to mack 02:86:45:5e:06:38 who-has 10.189.85.11 and no response.
And after that 1 request to all "who-has 10.189.85.11" and proper response.

On VM_DST:
tcpdump -i eth0 -e arp
13:41:41.886815 02:86:45:5e:06:38 (oui Unknown) > 02:25:6b:67:72:e9
(oui Unknown), ethertype ARP (0x0806), length 42: Reply 10.189.85.11
is-at 02:86:45:5e:06:38 (oui Unknown), length 28
13:41:42.888807 02:86:45:5e:06:38 (oui Unknown) > 02:25:6b:67:72:e9
(oui Unknown), ethertype ARP (0x0806), length 42: Reply 10.189.85.11
is-at 02:86:45:5e:06:38 (oui Unknown), length 28
13:41:43.890797 02:86:45:5e:06:38 (oui Unknown) > 02:25:6b:67:72:e9
(oui Unknown), ethertype ARP (0x0806), length 42: Reply 10.189.85.11
is-at 02:86:45:5e:06:38 (oui Unknown), length 28

3x response on previous 3 requests.
There is no request, only responses.
If vrouter send the response of request 'who-has 10.189.85.11' - the
response is on wrong VM.
If VM_DST OS should send this - on OS we don't see any request.

I think the response is send to wrong VM.

Additional info:

Contrail agent version:
 dpkg -l | grep contrail-vrouter-agent
ii contrail-vrouter-agent 2.20-64 amd64 OpenContrail vrouter agent

In attachements: video where you can see this behaviour

Screen from another network(compute nodes) with ping (first tab), tcpdump on SRC VM (second tab), tcpdump on DST VM (third tab): https://dysk.onet.pl/link/TKgXi

Changed in juniperopenstack:
importance: Undecided → High
Changed in opencontrail:
importance: Undecided → High
Changed in juniperopenstack:
assignee: nobody → Anand H. Krishnan (anandhk)
Changed in opencontrail:
assignee: nobody → Anand H. Krishnan (anandhk)
tags: added: vrouter
Nischal Sheth (nsheth) on 2015-10-27
Changed in juniperopenstack:
milestone: none → r3.0-fcs
no longer affects: opencontrail/trunk
no longer affects: opencontrail

bug update...

Hari Prasad Killi (haripk) wrote :

Based on the addresses shown, the response is going to the correct VM. Please explain the problem seen.

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