VSS on Cisco 6509 Switches

Unanswered Question


I am running VSS 1440 between two cisco 6509 switches. As of now, it supports only one supervisor per chassis. I have devices which are connected either of the two VSS members (single connectivity). VSL ports are on Supervisor Engine on both chassis. Now, if any of supervisor fails, what would happen to the devices connected to that switch? As per my understanding, those devices would lose the connectivity. I want to know whether the supervisor level redundancy can be achieved in this scanrio or not, if yes then how?


I have this problem too.
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Giuseppe Larosa Mon, 01/12/2009 - 02:12

Hello Punit,

you should add 10GE linecards on both chassis to be able to add links to VSL bundles.

Actually, VSS is thought for devices and servers that are multihomed.

Single NIC servers should stay behind an access layer switch with two uplinks

Hope to help


Giuseppe Larosa Mon, 01/12/2009 - 05:53

Hello Punit,

my understanding is that with VSL links a single supervisor can control both chassis so it should be possible for sup1 to control a linecard in chassis two.

Actually you can see the VSL as a way to export the backplane to join the two backplanes/switching fabrics.

For this reason is recommended to build the VSL bundle with ports of different linecards not only of the supervisors


And you should have dedicated links for dual-active detection if using BFD or fast hellos

That all this can work less then well is possible.

Hope to help


gkinney Wed, 02/25/2009 - 07:49

Hi, I'm currently working at configuring vss with 2 x 6509 chassis

supervisor module:Supervisor Engine 720 WS-SUP720-3B

10GB Module: WS-XS 6708 - 10GE


I've reviewed the majority of Cisco available solution however there are parameters that I'm not exactly sure how to optimize. If you could assist I would great appreciate it.




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