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New Member

Scavenger classification confusion

I am slightly confused as to the scavenger class recommended marking and how it relates to other traffic. The recommendation is to mark BE at IPP/DSCP 0 and mark Scavenger with CS1 (DSCP8)however 8 is above 0 so will surely get priority over BE traffic. Can someone explain this apparent anomaly, thanks.

New Member

Re: Scavenger classification confusion

Hi Ian,

I think I know the answer to this question. When they started kicking around the Diffserv RFC, they intended for it to include drop-bits and rates based on markings that would be greater than best-effort traffic. So Best-Effort was always DSCP0...I think subsequently thereafter, people needed a "class" or at least a way to differentiate bad/scavenger traffic against everything else...since there was no RFC for anything below 0, they had to standardize on a marking that was unique (and a high enough drop rate) ---so that DSCP8 was chosen. So at least now if you see stuff coming in with a CS1 marking on your routers, you can add a policer to it.

I heard someplace that there was some interest in extending the Diffserv RFC to include less-than-best-effort traffic, but if you really think about it, if you can differentiate that traffic with whatever marking, and then policing it, it really doesnt matter all that much.


New Member

Re: Scavenger classification confusion

Many thanks for your response