Subject: RE: The problem with tagging packets

From: Henry Clark <[email-masked]>
Date: Fri, 14 Nov 1997 08:40:32 -0500

At 10:51 AM 11/11/97 +0200, Kilkki Kalevi NRC/Hki wrote: 
>Secondly, every node must measure every individual flow and calculate the   
>drop preference level for every individual packet.

What processing requirement are needed to do this at OC-48c?

While I find many portions of this discussion intellectually
interesting, one has to wonder what would happen to the real
Internet if one wanted to implement the schemes proposed while
trying to handle BGP flaps and other dumb operational things
and simultaneously switching packets amongst an OC-48 or two.

henry

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From: "Eric S. Crawley" <[email-masked]>
Date: Fri, 14 Nov 1997 13:32:42 -0500

Henry,

While the boastful engineer in me wants to answer your question by saying
"We can handle this situation just fine, thank you", I believe you are
quoting Kilkki out of context.  

The whole purpose of tagging packets for differential services is so that
the core routers do *not* have to classify every flow and calculate the DP
for every packet.  If the edge routers perform the classification and
marking according to customer profiles, the core routers only have to look
at a few bits in the TOS byte to determine how to classify and queue a
packet.  This is a much smaller operation, in many architectures, than
classification by flow.

Kilkki was responding to a question about using just WFQ without any
tagging to manage congestion.

	Eric