icmp echo & FIFO

Unanswered Question
May 13th, 2008

It is often told that ICMP echo replies will be treated as low priority traffic and back seated. However, if an interface is participating in FIFO queueing then it stands to reason that they are forwarded in the order in which they are received.

Can anyone speak to this in one or another?


I have this problem too.
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bvsnarayana03 Tue, 05/13/2008 - 04:35

If policy-map is configured on interface & the link is congested then icmp takes the default-class. & when it reaches the interface queue or hardware queue, it is queued as FIFO.

Richard Burts Tue, 05/13/2008 - 04:56


The low priority for ICMP echo reply is not at the interface. You are correct that if the interface is operating in FIFO then the packets will be transmitted in order. But the low priority of ICMP echo is in the CPU processing to generate the response to the echo request.




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