[e2e] TCP to exhibit MTU unfairness?
detlef.bosau at web.de
Mon Nov 12 11:00:51 PST 2007
Lachlan Andrew wrote:
> Greetings Detlef and Daniel
> I think Daniel was pointing out that current TCP sets the window in
> terms of number of MTUs,
Excuse me, if I have something wrong in mind, but isn´t the window given
Or does this depend on the TCP flavour?
> and hence gives bandwidth proportional to the
> MTU of a flow. Flows using MTU=100 get roughly 1/15 of the bandwidth
> of flows using MTU=1500.
> Some people argue that this is correct behaviour if the actual
> bottleneck is the "packet per second" forwarding limit of a router,
> rather than the link capacity. However, I think that Daniel is right
Hm. I read the congavoid paper again and again and to my understanding,
the fairness issue tackled by congestion control is a _capacity_ issue....
> that it is normally undesirable unfairness.
If the window is given in MTU size units, I agree.
> On 12/11/2007, Detlef Bosau <Detlef.Bosau at web.de> wrote:
>>> Dear Community,
>>> I was wondering if there is something like "MTU unfairness"...
>>> similar to the probably not existing "RTT unfairness".
>> My basic question is: What is the ressource to be shared?
>> In TCP, the shared ressource is storage capacity along the path. The actual MTU size of a flow does not matter in this context.
>> So, it is not yet clear to me what you mean by "MTU (un)fairness" or "RTT (un)fairness".
Detlef Bosau Mail: detlef.bosau at web.de
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