3750E stack backplane throughput

Unanswered Question
Jan 29th, 2009

I have a customer with a switch stack comprised of 7 3750E-24-PD running c3750e-universal-mz.122-46.SE. The switches are running in StackWise Plus mode. This stack is providing the backbone of an elborate HD audio video system using Netstreams encoders and decoders. The customer has recently reported that he is losing video on some TVs. The encoder/decoder pairs use multicast groups to establish zones.

The vendor, Netstreams has asked what the throughput on the backplane of this stack is, as he believes it to be a backplane issue. I found that 'show controllers utilization' show percentage bandwidth figures. Are there any other commands that are useful in diagnosing backplane/switch throughput?

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glen.grant Thu, 01/29/2009 - 10:10

The show controllers utilization does tell you at the bottom of the display and how much is being used at that time.

ERNIE DULANOWSKY Thu, 01/29/2009 - 12:06

Thanks, Glen. That is indeed what I had seen and relayed to Netstreams. Are there other commands that can help monitor backplane throughput ?

Giuseppe Larosa Thu, 01/29/2009 - 12:27

Hello Ernie,

the first limit is that of the stackwise+ ring itself


This is the maximum theoretical ring speed (bandwidth) for a Catalyst 3750-E switch:


•64 Gb/s with a full or complete StackWise ring of Catalyst 3750-E switches.


see


http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/troubleshooting/switch_stacks.html#wp62394


so depending on how you cabled all the encoders if for example you have bundles using links from different switches you use more or less the stackwise+ ring.

So I don't think you can say that performance is 190 Gbps: it is between 64 Gbps and 190 Gbps depending on the setup and paths of traffic flows.


Hope to help

Giuseppe


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