NME-XD-24ES-1S-P Stackwise Backplane

Unanswered Question
Mar 31st, 2008

I am looking into the NME-XD-24ES-1S-P modules to interface a 3845 with two 3750 switches. The one question that I have has to do with the backplane.

Unless I read it wrong, the documentation seems to state the there is only a 1GB backplane connection between the switches and the 3845. Does anybody know if I read this wrong? If the backplane is the 32GB stackwise connection, I am sold but not if it is only a 1GB connection from the 3845 to the switches.

I have this problem too.
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htarra Fri, 04/04/2008 - 11:34

It is not possible to utilize 32 Gbps bandwidth for different switches/stacks as if they are individual entities, because you can use it by only redundant connection using stackwise ports within a single stack and not otherwise. Thus, you can use clusters within stacks but the 32 Gbic bandwisth will be within the specific stacks only.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.1_14_ea1/configuration/guide/swstack.html

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_25_sea/configuration/guide/3750scg.html

Joseph W. Doherty Fri, 04/04/2008 - 16:27

The 1Gbps limitation is between the switch module on the router and the router itself (the NME interface's bandwidth), not between the router's switch module and other 3750 switches via Stackwise cables (only available with the NME-XD-24ES-1S-P[?]).

The 3845, not the switch module, is hard pressed to substain even 1 Gbps of bandwidth, so additional bandwidth to/from the 3845, whether internal or external, would be unused.

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