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T1 Reponse Time Woes... Any ideas


I have a general question for anyone specifically working in the telco arena. I have started noticing a problem with latency. These are inter-lata links and NORMALLY they run around 53ms. Lately I've started noticing response times into the lower 60s. These links are leased point to point T1s using ppp encap. My configurations haven't changed and that's why I'm coming here. All of my interface counters look good, no errors, utilization is very low, normally around 14/255. Any suggestions or feedback is greatly appreciated and I will rate post



Re: T1 Reponse Time Woes... Any ideas

You carrier may have done some "grooming" and sent your traffic through a different path than the one you are used to seeing.

It may also be that some intermediate carrier (like a long distance trunk provider to your carrier) has re-groomed their circuits without specifically notifying your carrier.

Probably the best place to start is to talk to the carrier, have them check the path, pull the PM stats for the equipment handling your path, and see if they can find anything that's changed.

It might also be worthwhile to put an analyzer (like a Sniffer) in-line to check for things like re-transmissions. If there's a problem at one of the handoff points, some frames can be dropped (administratively or otherwise) .... the transmitter of the packet sees a timeout and re-sends the packet.

The re-tranmission symptom presents the same as higher latency; longer time to complete the dialog.

Given that you have a reasonable load and are showing no errors at your routers, the carrier seems to be the likeliest culprit.

Good Luck, let us know how it comes out.


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