[Iccrg] What's wrong with TCP Congestion control

[Simon Leinen]

Radek Krzywania writes:
> On Tue, 07 Feb 2006 01:50:29 +0100, S. Keshav <keshav at uwaterloo.ca> wrote:
>> 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)

> Maybe it is good to say explicitly, that large windows requires large
> memory buffers on sender and receiver sides.

The large buffer requirements are mostly due to the fundamental nature
of window-based transmission, independent of TCP's congestion control
algorithm: You need to support a large amount of unacknowledged data
(the window) to sustain the throughput, and you need the buffers at
the sender so that you can retransmit.

(The requirement for equally large buffers at the receiver seems more
like a constraint of the current prevailing interface to TCP in
end-systems.)

The only relation between TCP's congestion control and required buffer
sizes that I can see is when queueing at the bottleneck starts to
significantly increase RTT.
-- 
Simon.