Re: [58crew] RE: IETF58 - Network Status

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Iljitsch van Beijnum <iljitsch@xxxxxxxxx> writes:
> I think there is some middle ground between 25000 and 10 ms.

10ms is the middle ground. That's enough for a bunch of retransmits on
modern hardware. Coupled with aggressive FEC, that's more than enough
time.

> But the problem with sharing the airwaves is that you can't be
> sure how long it's going to take to deliver packets.

Actually, the speed of light is remarkably deterministic. If the
network is so loaded that you can't send a packet in that period, you
should drop so that all the TCPs back off.

> The difference between first try @ 11 Mbps and having to retry
> several times @ 1 Mbps can easily be a factor 40.

None the less, it ends up being much lower by orders of magnitude than
what the standards currently permit.

The packet dumps I got from the 802.11b networks during the worst
periods at IETF revealed what you would readily expect -- that TCP
collapses badly when the underlying network does something very dumb.

By the way, it would also be a good idea if the standard did proper
power control of the mobile stations.

-- 
Perry E. Metzger		perry@xxxxxxxxxxxx


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