Re: backbone routers' priority settings for ICMP & UDP

[John Hawkinson <jhawk () bbnplanet com>]

> This is not typically a policy that is carried out by the providers.  It is
> just how some router vendors have developed their implementations.  They
> don't give a lower priority to UDP or ICMP unless that traffic is destine
> for the router itself.

I think that this is insufficiently clear, though correct :-)

Non-optioned traffic *through* a cisco router running IOS
is always treated the same.

Traffic destined *to* one of the addresses on a router
is usually switched with a different switching mode (i.e.
"process switching"). Process switching is a seperate set
of queues on the router, and therefore a seperate set of delays.

Despite various assertions you might hear people make, process switching
is not likely to drop packets more frequently. It is likely to introduce
higher delay.

--jhawk