Switching Fabric and Forwarding Rate

[thanhnguyenhoc]

Hi all,

It is said that the switching fabric of WS-C3750X-24T-E is 160Gbps.

Could any body tell me what is switching fabric, any relevance or difference from forwarding rate?

Is there any document to know how will the switch reach the 160Gbps full switching fabric performance?

Please help to advise. Thanks a lot!

[Joseph W. Doherty]

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Posting

Switch fabric is the hardware that supports passing frames/packets between switch ports.

Switch fabric bandwidth, to carry full port capacity bandwidth, is, at least, 2x nominal port bandwidth.

So, for example, a 48 gig port switch, to pass all 48 Gbp between all ports concurrently would need to be 96 Gbps.

[thanhnguyenhoc]

Thank you for your answer.

Could you please explain how the switch fabric in this specific product, WS-C3750X-24T-E would need 160Gbps as stipulated in datasheet? (Ref

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/data_sheet_c78-584733_ps10744_Products_Data_Sheet.html)

Thanks a lot!

[Joseph W. Doherty · Accepted solution]

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

The WS-C3750X-24T-E doesn't need a 160 Gbps fabric.  Basically this capacity is shared across all models.  The 160 Gbps is needed for models with additional ports.

What this model needs is bandwidth for its 24 gig ports, its optional dual 10 gig ports and its 32 Gbps of stack ports, or 66 Gbps x 2 = 132 Gbps.

[thanhnguyenhoc]

Switch fabric is the hardware that supports passing frames/packets between switch ports. So, I think, a 24 gig port switch to pass all 24 Gbp and 2x10Gbps uplinks between all ports full duplex concurrently would need to be (24x2=48 Gbps) + (2x10x2=40Gbps)=98Gbps. Additional with 64 Gbps Stackwise Plus technology of stack ports, would totally need 98+64=162Gbps is correct.

Thanks a lot!

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Laugh - we're both math challenged.

(24x2=48 Gbps) + (2x10x2=40Gbps)=88Gbps

So, total fabric bandwidth requirement is 88+64=152Gbps