Re: [tcpm] Increasing the Initial Window - Notes

[Jerry Chu <[e-mail]>]

On Sat, Nov 13, 2010 at 5:51 AM, Marco Mellia <[e-mail]> wrote:
>
>
>> Browsers open lots of connections these days and we always try to cope
>> that in all our experiments.
>>
>> live:
>> To get the best possible apple-to-apple comparison when comparing IW10/IW3
>> performance on our live frontends, we split the client IPs into two (same
>> size) pools to serve IW10 and IW3 simultaneously. To our own surprise,
>> mobile hosts are among the big winners (even their browsers still open >2
>> streams per domain).  See slide 19 in our IETF 77 presentation
>
> Not surprised at all... since mobile terminal suffer higher RTT, it is quite
> straight forward to see larger benefit there.
> The point is that you cannot see the impairment of other traffic...
> It it easy to gain 20% when 20% of flows goes IW10.
>
> But what about the other 80% flows that were still using IW3? Was there any
> impairment for them?
> Easy answer: if there is no congestion and there is enough buffer space at
> the bottleneck link, then no impairment is expected.
> But if there is already some congestion, and then the bottleneck queue is
> already overloaded, then I expect  lot of impairment (and unfairness).
>
> And what would be the gain if 100% of flows goes IW10?
>
> Are the benefit larger than impairments? Then go for IW10, or even IW16.
>
> Those are questions that your data cannot answer I would say.
> Has someone run at least some simulations to see what can happen on a
> congested path?

Have you at least checked the title of our most recent presentation in
Beijing to
know it might contain some relevant data for your question?

Best,

Jerry

>
> Ciao
> Marco
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