Prioritization... (RED?)

Bradley Reynolds brad at
Tue Dec 8 23:12:42 UTC 1998

One tidbit that is interesting: dwred on the 
cisco gives non tcp packets the lowest possible
priority.  Thus, with an aggressive drop pattern
(depending on how you have configured minth, maxth and
exponential weight on the router) you will run into a problem.

I am not sure as to who has dwred configured on congested
interfaces at exchanges.  You can throw packets
into one of 8 precedence levels @ your border and 
then craft red to select harshly against low vs. high
priority.  However, upon observation of a network
without car matching certain types of traffic and
setting priorities, i see about 3 orders of magnitude
difference in packets moving at the lowest precedence
compared to packets moving at higher precedences.  
RED considerations are not necessarily the cause
of your problem, but it is a possibility which is
worth investigating.

more cisco implementaion specific information at:


On Tue, 8 Dec 1998, Rich Sena wrote:

> Got a question - been trying to track some loss I've seen in our traffic -
> and one of the things that came to mind was packet priority and a lower
> priority being set for UDP at some exchanges - especially congested ones.
> Anyone here doing such - snd if so does anyone have anysort of data re:
> how much of that traffic is being dropped...
> -- 
> I am nothing if not net-Q! - ras at

More information about the NANOG mailing list