Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header

Nick Hilliard nick at
Fri Sep 30 16:38:09 UTC 2011

On 30/09/2011 17:30, Christopher Morrow wrote:
> traceroute is really an example of 'packet expired, send
> unreachable'... that, today is basically:
>   o grab 64bytes of header (or something similar)
>   o shove that in a payload
>   o use the src as the dst
>   o stick my src on
>   o set icmp
>   o crc and fire
> there's not really any need to do this in the slow path, is there?

there are unconfirmed rumours that icmp ping and traceroute are handled by
hardware on the asr1k.  I don't know if they are true.   But you're right -
it would be good to support this without resorting to hammering the routing
engine.  I don't really like the idea of punters running traceroutes
reducing my bgp convergence time.


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