[j-nsp] router dropping packets where there is no reason anywhere to be seen

[Alexander Koch]

Folks,

when asked to debug a problem for a close friend I stumbled
over what they have. Consider a M160 router, an OC48, some
ae to some Black Diamond switches, and some traffic, but all
around 300-400 Mbit/s, and one GE at 700.

I was wondering as I had some nasty things popping back up,
namely that due to the different architecture policers on a
M20/M40 (which do what you tell them) where quite hazardous
on our M320s.

Also I seem to remember (correctly, I hope) that when no
class-of-service is configured some default stuff kicks in,
and there is an occasional drop here and there, just because
of the default stuff.

The symptoms are easy, packetloss on the box and especially
so through the box. Debugging this can be nasty, yes. What
caveats are there for the M160 and default QoS and default
policers for the RE (lo0). Also what is the default ARP
policer, as that might have been an issue in the past as
well. 20K MACs are now handled through the BD switches, mind
you.

Does anything I write here say anything to anyone? Would QoS
help? I would say yes here, but our backbone ourselves is so
feature- rich that I might be comparing Apples to Dells. ;->

Thanks for any feedback.

Regards,
Alexander