IP Cef load-sharing query

Answered Question
Feb 1st, 2007

I have a MLS with 2 links that advertise the default route. IP cef is enabled on a per-destination basis:

0.0.0.0/0, epoch 3, RIB, refcount 6, per-destination sharing

Why, then, when one of the links had a fault and was effecively down (not passing default traffic but still advertising the link), when I pinged a route that would take the default, e.g. 192.168.12.9, I got the following:

3750A#ping 192.168.12.9

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.12.9, timeout is 2 seconds:

!.!.!

This looks like per-packet sharing to me, or have I misunderstood?

Thanks, J

I have this problem too.
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Correct Answer by Richard Burts about 9 years 7 months ago

You are seeing the difference between what IOS does for traffic being forwarded THROUGH the router and what IOS does with traffic generated BY the router. Traffic being forwarded through the router does perform per destination. But traffic being generated by the router (like your ping) will do per packet sharing.

HTH

Rick

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Correct Answer
Richard Burts Thu, 02/01/2007 - 03:16

You are seeing the difference between what IOS does for traffic being forwarded THROUGH the router and what IOS does with traffic generated BY the router. Traffic being forwarded through the router does perform per destination. But traffic being generated by the router (like your ping) will do per packet sharing.

HTH

Rick

Richard Burts Thu, 02/01/2007 - 07:40

Narayan

Anything generated by the router itself (including extended ping) is process switched and will packet by packet load share.

HTH

Rick

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