VSS and etherchannel problem...

[Shaik Moinuddin]

Hi,

we have 2 physical chassis of Cisco Catalyst 6506-E logically combined as one thru VSS and we have 2 Cisco WLC 8510 connected to these 2 Cores thru port-channels. the problem is WLC traffic always choosing only one chassis ports regardless of which Core is Active.

any help would be appreciated.

[Mark Malone · Accepted solution]

Hi

have you tried changing the load balance mechanism for the port-channel to aplit the traffic ccross both links

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-virtual-switching-system-1440/109638-vss-pf-tshoot.html#eclb

[Shaik Moinuddin]

Hi,

thank you very much Andy and Mark....

regards,

Moin

[andrewswanson]

Hello
Are you connecting the WLC to VSS as a multi-chassis etherchannel?

WLC documentation:
"Make sure the port-channel on the switch is configured for the IEEE standard Link Aggregation Control Protocol (LACP), not the Cisco proprietary Port Aggregation Protocol (PAgP)."Controller only supports the on mode of the LAG.

VSS multichasis etherchannek documentation
Do not use on and off options with PAgP or LACP or Trunk protocol negotiation.

hth
Andy

[Shaik Moinuddin]

Hi Andy,

i think its PAgP, please have look at attached file of screen shot.

regards,

[andrewswanson]

Hello
The screen shot shows you are using multichassis etherchannel (interfaces Te1/1/9 and Te2/1/9) with mode on (protocol field is blank - see http://jamsudsanusi.net/2014/07/cisco-etherchannel-mode/)

Are your 2 WLCs an HA pair?

Cheers
Andy

[Shaik Moinuddin]

Hi,

yes our 2 WLCs in HA pair.

regards,

[andrewswanson]

Hi Shaik

You could connect each WLC to a single VSS chassis and still have WLC HA.

hth

Andy

[Shaik Moinuddin]

Hi Andy,

but the problem is not WLC HA, why WLC traffic always prefer one VSS chassis ports. when VSS chassis 1 is Active then the Te1/1/9 getting utilized and when VSS chassis 2 is Active then also Te1/1/10 getting utilized, why Te2/1/9 not get used? the only time when VSS chassis 2 Port getting used when VSS chassis 1 is down or Port SHUTDOWN.

regards,

Moin

[andrewswanson]

Hi Shaid

In that case, check Mark's post below to look at the port-channel load balancing mechanism.

Regards

Andy