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VSS with Cisco 6500s with dual sup 2T



I'm wondering if anybody has any information about the following scenario:


We're trying to implement VSS between 2 catalyst 6500.

Each catalyst 6500 will have dual 2T supervisors, so, in total we would have 4 supervisors.


Question is: is it required to have the exact same IOS version on all of the 4 supervisors?


A Cisco SE mentioned that we could have the primary supervisor on each chassis with IP Services (we do need routing features) and the redundant supervisor with IP BASE. We're very concerned about this as we understand that IP Services entitlement is just for one supervisor.


Any thoughts?




Hello, I am quite shocked

Hello, I am quite shocked that a Cisco SE would advise you of this.

I would highly recommend having the same license installed on all SUPs in a VSS, with same version of code.

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Hello Bilal, I was so shocked

Hello Bilal,


I was so shocked too, the problem is that we considered the 4 supervisors with the same IP Services IOS but for a reason I can't explain, Cisco's SE told the customer it was not necessary to have the 4 supervisors with IP services but just 2 of them and the other 2 IP BASE.

I'm looking for an "official" document so I can proof the same IOS is necessary on all of the supervisors.

The only reason I can

The only reason I can possibly think is that IP BASE may support VSS and so does IP Services (therefore he/she/they didn't see a problem with this) - However major problems exist when you have IP services features enabled and in the event of failure switch to IP Base - you will no longer be able to use features.

Even just generally with VSS and SUPs providing the capability - one would think that it would be best/good practice - even common sense to keep all SUPs exactly the same.

Having said this, your license/feature set is within the IOS image I believe. I'm not sure how licensing works here, but you could put the same images with the feature sets/license on the secondary SUPs in both chassis. If one SUP fails the secondaries take over but with the same license/IOS.

Perhaps someone can clarify on this matter, who has more knowledge on this space. Other than that, it could be a case of copy the image to the supbootdisk of the second SUP in both chassis.... Then conversion to VSS.

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At face value this

I share Bilal's concerns.

At face value this recommendation from the SE makes does not compute.

I worked for one customer that purchased 16 x 6513's each with 2 x Sup 2Ts. Each pair of 6500's was running Quad VSS.

You only purchase one license for each VSS 6500 chassis.

At face value the SE's recommendation will double the licensing cost for each 6500 since he/she now wants you to buy 2 x licenses per box.

Even if it worked it makes it very complicated from an operational support point of view. You now need to document that each Sup has a different version of code. Who is going to remember that at 3:00 am in the morning if your switch fails?

Community Member

Thanks Bilal, Sean,But then,

Thanks Bilal, Sean,

But then, would one single IOS be enough for the chassis with 2 supervisors?

Don't each supervisor need its software? Is the software paired with the chassis no matter how many supervisors are installed on it?


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