[c-nsp] GSR 12008 physical loop ping problem?

[Oliver Boehmer (oboehmer)]

Sortin,

> I'm bothering you with another possible problem i've discovered today,
> while trying to test this router and some linecards before i put them
> to work ;)
> 
> So... i looped an STM-1 interface with a Fiber patch, the line
> protocol went up, and i could ping the interface (HDLC encapsulation),
> but, see below:

> Sending 100, 4470-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:
> !.!.!.!.!.!.!.!.!.!.
> Success rate is 50 percent (10/20), round-trip min/avg/max = 1/1/4 ms
> Router#p

bort.
> Sending 100, 750-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:
> !!!!!!!.!!!!!!!.!!!!!!!.!!!!!!!.!!!!!!!.!!!!!!!.!!!!!!!.!!!!!!!.!!!!!!
> !!.!!!!!!!!.!!!!!!!!.!!!!!!!!.
> Success rate is 88 percent (88/100), round-trip min/avg/max = 1/1/4 ms
> Router#p

> 
> Only if i ping with small packets, i don't have packet loss.
> 
> The STM-1 port isn't broken. I connected it into another router, and
> it works fine with 4470 bytes pachets with DF set.
> 
> Should this happen?

Please check out CSCea11267 (pinging to own POS interface fails). We
heavily rate-limit this ICMP traffic (i.e. sourced from our own address)
towards the Linecard CPU, this is why it works with smaller pings (less
traffic).

	oli