high latency on serial interface on Cisco 3845

Unanswered Question

Hi,

Am experiencing a very strange phenomenon which i hope someone can help shed some light. Am migrting a site from an old Cisco 3660 router to a new CIsco 3845 router. The old router had serial connections to branch offices configured as multilink bundles, then everything was ok. When the new router was brought in with the same serial terminations to the remote branches the links become bery unsteady with high latency. Below is an output of ping:

Reply from 128.1.5.1: bytes=32 time=2088ms TTL=254
Reply from 128.1.5.1: bytes=32 time=2454ms TTL=254
Reply from 128.1.5.1: bytes=32 time=2362ms TTL=254
Reply from 128.1.5.1: bytes=32 time=2108ms TTL=254
Reply from 128.1.5.1: bytes=32 time=1644ms TTL=254
Reply from 128.1.5.1: bytes=32 time=307ms TTL=254
Reply from 128.1.5.1: bytes=32 time=1246ms TTL=254
Reply from 128.1.5.1: bytes=32 time=1379ms TTL=254
Reply from 128.1.5.1: bytes=32 time=46ms TTL=254
Reply from 128.1.5.1: bytes=32 time=10ms TTL=254
Reply from 128.1.5.1: bytes=32 time=14ms TTL=254
Reply from 128.1.5.1: bytes=32 time=10ms TTL=254
Reply from 128.1.5.1: bytes=32 time=10ms TTL=254
Reply from 128.1.5.1: bytes=32 time=10ms TTL=254
Reply from 128.1.5.1: bytes=32 time=10ms TTL=254
Reply from 128.1.5.1: bytes=32 time=10ms TTL=254
Reply from 128.1.5.1: bytes=32 time=10ms TTL=254
Reply from 128.1.5.1: bytes=32 time=11ms TTL=254

The link keeps fluctuating like that the whole day and night with packet drops at times. When we move the links back to the old router everything works fine with minimal latency and no packet drops.

What could be the problem and how can i go about solving this issue.

Thanks,

Jerry.

I have this problem too.
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Giuseppe Larosa Fri, 09/17/2010 - 06:24

Hello Jerry,

post the configuration of serial interfaces and related controllers for both the old router and the C3845.

It may be a problem of controller configuration on the new router related to clocking aspects as bundles are involved.

Actually, depending on network module type a separate controller object may exist of not.

Hope to help

Giuseppe

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