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Strange result while ping serial interface

  • From: Yu Ning
  • Date: Wed May 10 21:42:44 2000

Hi nanog,

Strange thing happens everyday. When I were troubleshooting yestoday,
I found a ping to my local serial interface (no matter it's 155M POS, 
or 2M Serial interface) takes nearly twice delay compared with a ping 
to the remote side of the serial interrface ! When I trace to my local
serial interface, I got the first hop to the remote end, then second
hop back to my local interface ! 

For example, is local serial interface, while 2.2 is remote
side. A trace on 2.1 to 2.1 first go to 2.2, then back to 2.1. And this
situation can be verified on both side.

Have you ever seen this situation ? Is it due to our misconfiguration?
or it's sheerly a mis-display of result in Cisco box (can't believe it)

The background is: we're using ISIS as IGP, and utilized level-1/2 link.

thanks for any input.


Yu Ning
(Mr.) Yu(2) Ning(2) 
ChinaNet Backbone Operation
Networking Dep.,Datacom Bureau
China Telecom.,Beijing(100088),P.R.C