Cisco VSS clarification

Posted on 2012-08-26
Last Modified: 2012-08-26
Hi All,

At a customer site, there is currently two Catalyst 6509-E chassis populated with line cards and  supervisor modules (WS-SUP720-3BXL). The two Catalyst switches aggregate all connections from the many client access switches. Everything is working fine.
The tricky part is that one of the Catalyst 6509-E has two supervisor modules (WS-SUP720-3BXL) in slots 5 and 6 with one being active and the other in hot standby mode.
Now, there is a need to implement VSS on these switches. Two VSS-capable supervisor modules (VS-S720-10G-3C) have been purchased.
I intend to replace the existing supervisor modules with the VSS-capable ones and then deploy VSS across the two chassis.
My question here is;

1) Should i take out the hot standby supervisor as well from the chassis that presently contains two supervisors.

2) What are the implications if i leave the hot standby module in place after implementing VSS.. Can bad things happen.

My thinking is to take out both supervisors. I just want to be sure that I am not missing out on anything i should know.

Please note that implementing VSS is not an issue for me, as i have experience deploying VSS. I just havent deployed at a site that has two supervisors in one chassis. I have often run into situations where there is only one supervisor in each chassis.

Thanks in anticipation.
Question by:olaolusijuwola
    LVL 17

    Expert Comment

    I may be mistaking, but redundant Sup engines can't be mixed, but have to be the same model... so keeping the old standby engine with the new engine will probably not be supported by either hard- or software ...

    Author Comment

    Thanks Garry-G.
    If i get you correctly, you are saying it doesnt matter if i take out or leave in place the redundant Sup engine, as it won't be support and hence would not be disruptive in any way.
    Is this what you meant?
    LVL 17

    Accepted Solution

    I couldn't find any docs on how a 4500/6500 will react with different SUPs inserted, but reading up on SUPb redundancy clearly states that the same hardware (down to PFC and MFC) has to be used... therefore, I'd recommend throwing out the old SUP, as it would in best case not help any, worst case could cause problems...

    Author Closing Comment

    Exactly the answer I was looking for.  Thanks a million.

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