[e2e] end2end-interest Digest, Vol 17, Issue 26

S. Keshav keshav at uwaterloo.ca
Wed Aug 3 13:02:35 PDT 2005

> I think of RED strategies, I remember a strategy where there
> are two thresholds a, b, a < b, for a queuelength q. If q < a, packets
> are accepted. If b < q, packets are rejected. If a <= q <= b packets are
> rejected randomly with a probality p which is linear increased from p=0
> if q=a to p=1 if q=b.
> Question: Would it make sense to chose a and b that way, that
> i) q has a constant expectation and
> ii) q has a constand variance
> for certain periods of time?
> However, I expect that someone has discussed this before, it?s just too
> simple.

The easiest way to make the queueing delay constant, or nearly so, is to
introduce wait times where the link is idle even though there are packets in
the queue. This reduces delay jitter in the system and makes the whole
network more circuit-like. By introducing new 'work', the system is what is
called 'non-work-conserving'. Such systems were studied extensively in the
early 90's. For more details, you should look up Hui Zhang's comprehensive
survey on scheduling: "Service disciplines for guaranteed performance
service in packet-switching networks" Proceedings of the IEEE, Volume 83,
Issue 10,  Oct. 1995 Page(s):1374 - 1396.

hope this helps


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