Does a new Supervisor improve round-trip time?

Unanswered Question
Apr 9th, 2010

Hi Experts! Please help me with the some doubts about connectivity time. 2 months ago I did some ping tests and I got round-trip time aprox. 800ms between Host_A and Host_B:

Host_A ---> Router_X (7609) ---> Router_Y (7609) ---> Host_B

1 week ago, I installed a new Supervisor in Router_A, I replaced an old SUP720-3B with a new RSP720-3C. Now, I have round-trip time aprox. 150ms.

1) Does the new Supervisor decrease round-trip time?

1) New Supervisor has better performance, does it improve delay time?

1) Is there any document to check this behavoir?

Thanks a lot for yur help!



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Giuseppe Larosa Fri, 04/09/2010 - 11:55

Hello Carlos,

unless you did tests over an extended period of time my guess is that when you did the first test one link on the path was experiencing congestion.

When you see a so high delay this means there is congestion unless you are using satellite links

You are not pinging the supervisor if my understanding is correct, so these packets are processed just as standard user traffic.

What is the link between the two C7609 ? What linecard or service card (SIP or other flexwan)?

unless it is a WS-6708 or WS 6716  that has a DFC 3C onboard that matches with PFC 3C on RSP 720 3C ,there is no other difference

what was the IOS image used on the sup720?

Likely the RSP 720 is running a newer IOS image.

So generally speaking the answers to your questions are negative.

the RSP 720 can improve routing convergence on learning BGP full tables thanks to its MSFC4 that is better then MSFC3 in sup 720.

A possible difference can be the number of IP prefixes that can be handled by older sup 720 3B and RSP 720 3C but I think they both support 256,000 routes

see datasheet

Hope to help



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