VSS (Virtual Switching) and CAT2960

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Mar 26th, 2009
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Hi there,

this is an easy question.

Does cat 2960 support Virtual Switching as cat 6500 does: 2 switches connected in some way making a unique unit?

Is just to try to make an EtherChannel or Link Aggregation (LACP) between a Server an 2 2960.


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Overall Rating: 5 (2 ratings)
Jon Marshall Thu, 03/26/2009 - 05:12
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I'm afraid not. The 2960 switches are not stackable so you will not be able to create an etherchannel across 2 switches.


iraira Thu, 03/26/2009 - 06:44
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Thx a lot fpr your answer Jon.

But I was not meaning stackability, which is similar but not the same as VSS.

I have read in IOS software release 12.2(46)SE for cat 2960 something that drives me to confusion:

"Cisco Catalyst 2960 Switch Software Update Available

Cisco IOS Software Release 12.2(46)SE enhancements include Multi Domain Authentication, and Enhanced Port Aggregation Protocol to support the Virtual Switching System."

Does it mean tah 2960 supports VSS itself?

Or does it mean that 2960 supports PAgP to a different VSS system?

Could you clarify?


jpoplawski Thu, 03/26/2009 - 15:36
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That means it supports PAgP for the uplinked VSS unit (whereas the 2960 can assist the VSS unit in dual active detection). This unit does not operate in VSS(65xx) or stackability(3750) mode.

Hope this helps, rate if it does!


Joseph W. Doherty Fri, 03/27/2009 - 04:50
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Since the OP asked about Etherchannels, I recall(?) the 2975 might lack cross member Etherchannel support (as supported by the 3750 and 3750-E series).

glen.grant Fri, 03/27/2009 - 06:04
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2975 does support cross stack etherchannel same way the 3750's do .

Joseph W. Doherty Fri, 03/27/2009 - 08:09
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Interesting! I don't always recall everything correctly; did some more research.

Backgound: When the 2975 was announced, I examined it as a replacement for 3750 stacks where L3 wasn't needed. Since cross-stack Etherchannel was a required feature, dropped them from consideration when found it not supported. (Question is, where did I find this information?)

Just now, looking at the 2975 configuration guides, cross-stack Etherchannel is described much like a 3750s.

Did some more digging and found an eight page paper received, from Cisco, which on page 2 states "Stacking similar to 3750 StackWise except no support for cross-stack features", and on page 3, "Cross-stack EtherChannel, FlexLink, and SPAN are not supported on the Catalyst 2975".

Well at least my memory, in this case, wasn't faulty, but would like to know whether cross-stack EtherChannel is supported on 2975 or not. Has anyone tried it?

David Cebula Mon, 04/20/2009 - 09:13
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I checked the Configuration Guide for 12.2(46)EX. EtherChannel, Flexlinks and SPAN are covered. Cross-stack etherchannels are mentioned. Nothing in there states that those features do not work within a 2975 stack.

Can someone confirm? The lack of information on 2975's on Cisco website is furstrating.

felixdav Sat, 05/09/2009 - 08:00
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Cross-stack EtherChannel, FlexLink, and SPAN is now officially supported on the Catalyst 2975. No software upgrade is needed.

Joseph W. Doherty Sat, 05/09/2009 - 13:53
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Now or real soon? I recall Cisco tech rep said it will be coming.

If now, what software version(s) is it supported?


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