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Ping Response on a serial Link

When I ping my own router serial interface, the response time is more than when I ping the other end of the serial connection. Can I know the exact reason? I am using HDLC as encapsulation on the serial links?

I guess most of us havent tried doing this.


Re: Ping Response on a serial Link

When you ping your local interface on a ptp link your router will actually send the icmp echo request across the link and the remote router will redirect this echo-reply back to the sender. This redirect seems to take a bit longer than a direct reply (icmp echo-reply). If you'd like to test this you can do a debug ip packet (ON A TEST ROUTER) on the remote side and you'll see something like this.

On remote: (debug ip packet)

5w2d: IP: s= (Serial0/1), d= (Serial0/1), len 100, redirected

5w2d: ICMP: redirect sent to for dest, use gw

On local: (debug ip icmp)

5w2d: ICMP: echo reply sent, src, dst

5w2d: ICMP: echo reply rcvd, src, dst

Hope this helps answer your question,


Community Member

Re: Ping Response on a serial Link

Hi Don ,I had the similar problem as the sol u have given .Still I am not clear why doenot show show ip redirects that packet has been redirected.Moreover do only first packet gets redirected or all the packets get redirected.I know its only first..But why doesnot it shows in show ip redirects.Please clear my doubts.

For further refrence to the problem u can refer to "Some interesting thing about PING our interface " on the dec14 and comment on that part.

Thanx in Advance.



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