Are Flex Links supported across a 6500 VSS?

[sdeckert]

Hi there,

Just having some issues getting a Flex Link working across a 6500 VSS, where the active a backup interfaces are on different physical chassis members.

Even though the backup interface is patched and the remote switch is showing the link as being up, the Cisco side is still showing it as down as per below:

6500switch#sh int switch back

Switch Backup Interface Pairs:

Active Interface        Backup Interface        State
------------------------------------------------------------------------
Gi1/1/1                 Gi2/1/1                 Active Up/Backup Down

Even if the active link is disconnected, the backup link still does not come up.

Can't seem to find a  definite answer in the documentation, or though google / forum searches.

Has anyone come across this?  Know if it's supported?

Cheers,

Sam.

[Reza Sharifi]

Hi Sam,

I have not seen a document that discusses Flex Links with VSS and not sure if it is supported. The common way of doing it is to bundle up your 2 uplinks in to one Etherchannel.

HTH

Reza

[sdeckert]

Hi all,

FYI confirmed with the TAC that it is a supported configuration - the issue I appear to be having is to do with with physical backup link itself - will be doing some more troubleshooting today.

Cheers

[danrya]

It is supported, but note in this document that:

If FlexLinks are configured on the VSS, we recommend using the PAgP detection method. Do not configure FlexLinks and BFD dual-active detection on the same VSS.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/vss.html#wp1063892

Dan