latency for l2 vs l3 interface in 6500

patil.ajay · ‎07-02-2013

Hello,

We have configured a layer 2 vlan in 6500. traffic coming from gigaethernate interface and going out from 10G towards the servers.

e.g. source interface g4/3, is a access port.

destination interface is trunk(router on stick configuration. Te1/1

We are planing to change 6500 configuration to L3 SVI, so that there will be an interface Vlan 100, and port g4/3 is access port in vlan 100. It will routed tru a routed port of Te1/1.

The physical path will be the same, only logical path altered, Will there be any increase in latency?

Reza Sharifi · ‎07-02-2013

Hi,

If you are using sup-720, both layer-2 and layer-3 is done in hardware at about 400Mpps. So, there should not be any increase in latenacy.

See table-1 in this link:

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/product_data_sheet09186a0080159856_ps2797_Products_Data_Sheet.html

HTH

Joseph W. Doherty · ‎07-02-2013

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Posting

Zero additional to not enough additional latency that you'll notice.

patil.ajay · ‎07-02-2013

Thanks for your inputs.

how the latency will increases? or delay added?

If apply access list

or If we configured qos policy

or a logical hop addition?

Joseph W. Doherty · ‎07-03-2013

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

Generally on L3 switches, like the 6500, all "normal" (packet processing) features are supported by special/dedicated hardware. So, there's very, very little additional latency introduced.

However, there are "abnormal" or unusual situations, that may be caused by the nature of your traffic or the feature you're using that the special hardware doesn't support. In those cases, the traffic is processed by the CPU of the switch, which is much, much slower.