[Iccrg] What's wrong with TCP Congestion control
keshav at uwaterloo.ca
Tue Feb 7 00:51:12 GMT 2006
Here is a list paraphrased from mail so far:
1. Unsustainable large equilibrium window sizes under high bandwidth-delay
product environments; requires an unrealistically low loss probability.
(Leads to limited dynamic range)
2. Low throughput under lossy environments because of using loss as an
indication of congestion.
3. Slow additive increase: Takes a long time for flow to catch up with
spare capacity and results in unnecessary long flow-completion times.
4. Inefficient Slow-start: Even when the flow is capable of completing
within a round-trip time, slow-start makes flows last multiple round-trip
times just to find their fair share rate. Often most flows complete
before they exit slow-start phase.
5. Large queueing delay: TCP fills up any amount of buffering available at
the bottleneck links. Results in long latency.
6. Unfair bandwidth sharing: shares bandwidth inversely proportional to
7. TCP builds a standing queue at the point of congestion, which increases
Did I miss anything?
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