11-01-2016
03:27 PM
- last edited on
03-25-2019
03:48 PM
by
ciscomoderator
We are testing a EoMPLS VC type 5 / Ethernet vc in our lab on VSS setup and not able to pass traffic. The VSS is Sup2T (15 + code) and we have a single AC connected to switch 2 of the VSS.. with switch 1 currently having the active sup in the system. The vc comes up/up like normal all mpls testing end to end looks fine however the pw will not pass traffic.
When we move the ac to a port on switch 1 of the vss all works as expected... the vss has no upstream mec.. rather just dual links up. (one on each chassis).. with the active ip path out switch 1 for the lsp.
In theory we would expect traffic from the AC to come in switch 2 go across the VSL and go out... are we missing something very obvious with mpls and vss ??
thanks!
11-02-2016 01:08 AM
Hello Arthur,
what does the configuration of the VSL look like ? There are not really many options on how to configure the link, but can you post the config ?
11-02-2016 08:20 AM
Arthur and I have been working together to get this up and running, so here are configuration snippets from the VSL in question:
interface Port-channel131
description VSL link to Switch 2
no
no
no platform
switch virtual link 1
!
interface Port-channel132
description VSL link to Switch 1
no
no
no platform
switch virtual link 2
!
interface TenGigabitEthernet1/5/4
description VSL link to Colo 2 Te5/4
no
no
no
channel-group 131
!
interface TenGigabitEthernet1/5/5
description VSL link to Colo 2 Te5/5
no
no
no
channel-group 131
!
interface TenGigabitEthernet2/5/4
description VSL link to Colo 1 Te5/4
no
no
no
channel-group 132
!
interface TenGigabitEthernet2/5/5
description VSL link to Colo 1 Te5/5
no
no
no
channel-group 132
!
11-02-2016 09:52 AM
Hello,
the configs look good. The only thing I found in the best practices paper was that they added this to the port channel:
mls qos trust cos
no mls qos channel-consistency
11-02-2016 12:27 PM
If it helps... here is a basic diagram of the overall setup as well. Essentially, when we have CE-1 connected to VSS-SWITCH-1 everything works as expected, but as soon as we physically move CE-1 over to VSS-SWITCH-2 we are unable tp pass traffic between CE-1 & CE-A. The VC is up in both situations, but traffic does not flow.
11-02-2016 02:07 PM
William, Arthur,
can you try this: connect CE-1 to VSS-Switch-2, but disconnect the link between VSS-Switch-2 and Router-2 ? I am starting to wonder if there is some sort of routing loop in your setup...
11-03-2016 03:01 PM
We cannot change upstream links do to the production state of the chassis. If a routing loop existed it should also break the successful test when the ac is on switch 1 ? vss is a single control plane.... unless I am missing something.
11-07-2016 03:11 PM
We have rebuilt this environment in our lab, and disconnecting the link between VSS-Switch-2 & Router-2 did not resolve the problem.
All traffic except the MPLS
Once we built the lab we saw the same issue, wherein when the end device was connected to VSS-Switch-1, traffic flowed without issue, but once the end device was moved to VSS-Switch-2, traffic stopped flowing even though all MPLS attributes do not show any problems.
11-08-2016 12:33 AM
Hello,
based on the document below, you might want to try and set the load balancing method of the port channel to mpls:
port-channel load-balance mpls
I am not sure what difference that would make, but since the obvious doesn't work, we might as well try the not-so-obvious.
Also, try and set the mls ip cef load-sharing to 'full'. Again, I am not sure what the effect is, but since you are in a lab enviroment, nothing bad can happen:
mls ip cef load-sharing full
Here is the link to the document I have been looking at:
http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-virtual-switching-system-1440/109638-vss-pf-tshoot.html
12-01-2016 07:00 AM
SOLVED: We were able to resolve this problem by adding the following command to the VSS cluster as well as any potential PE devices:
'mpls ldp graceful-restart'
Once this command was entered we restarted all LDP neighborships using:
'clear mpls ldp neighbor *'
Once this had been completed on all potential PE devices we were able to pass traffic across the pseudowire as expected.
12-01-2016 08:17 AM
William,
great stuff, good to know that you got it solved. I actually thought that command was only necessary for SSO/NSF, apparently it is also needed in VSS.
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