[e2e] Congestion control as a hot topic in IETF
detlef.bosau at web.de
Tue Mar 5 08:40:17 PST 2013
Am 05.03.2013 13:07, schrieb Scharf, Michael (Michael):
>> Am 04.03.2013 23:07, schrieb Scharf, Michael (Michael):
>>> There has been some interesting research on whether a
>> transport protocol could work without any congestion control.
>> One reference is: B. Raghavan and A. Snoeren, "Decongestion
>> Control", ACM SIGCOMM Workshop on Hot Topics in Networks, 2006.
>> I remember that you, some years ago, asked whether networking
>> can be done without flow control.
> My comment is about network designs that typically assume erasure codes and flow-based queueing/scheduling in all network nodes. Actually, it took me a while to fully understand why this is no alternative to the way Internet congestion control works today. But, for what it is worth, I found the overall idea intesting.
It's perhaps not the focus of this discussion, but you perhaps remember
our private discussion years ago, where I started to make a difference
between bandwidth and throughput, particularly as the "throughput delay
product" is something completely different from the "bandwidth delay
product". These are perhaps no central aspects of our discussion,
however it somehow illustrates where some of the confusion may come from.
And I made quite some turnarounds myself during the last years. Starting
from mobile networks, as you may remember, ending up in the insight that
VJCC does not really work with a single mobile wireless link
(!!!!!!!!!!!!!!!) and that this does not change if we put 30 wired links
in advance of the mobile one and 50 other behind - and then argue that
VJCC will work end to end.
No. Like in maths, one counterexample disproves a theorem.
However, different from math, VJCC is not a theorem but a mechanism
based upon quite some, if implicit, assumptions. So it may well be, and
actually is the case, that these assumptions do not hold in some network
so VJCC is not applicable and may lead to unwanted results.
This is no way a disaster, it is some kind of collective learning.
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