[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[ih] internet-history Digest, Vol 84, Issue 11

It wasn't just Nagle. LeLann, Gelenbe, and others were doing research 
on this topic in the early 1970s, it is discussed in IEN#1 in 1977 
with the conjecture that ingress flow control was likely to be part 
of the solution, there was a conference held on the topic in 1979, 
and Jain's work begins about this time and is published in '82.

It seems lots of people understood the problem and were investigating 
possible solutions.

Take care,

At 2:04 PM -0400 5/23/14, Noel Chiappa wrote:
>     > From: Bob Braden <braden at ISI.EDU>
>     >> I haven't read Nagle's thing, but that would also be interesting to
>     >> look at, to see how much we understood at that point.
>     > We were of course aware of Nagle's conclusions at the time, but I don't
>     > think I actually read his RFC on congestion collapse until a few months
>     > ago. It is well worth reading.
>Indeed it is. Numerous gems; he probably understood the issues better than
>anyone else, before Van. Some of them:
>   Adding additional memory to the gateways will not solve the problem.
>How true! A lesson some people have just (re)-learned recently!
>   the ICMP Source Quench message. With careful handling, we find this
>   adequate to prevent serious congestion problems. We do find it necessary
>   to be careful about the behavior of our hosts .. regarding Source Quench
>   messages.
>Interesting! This appears to be experimental data to support my thesis, that
>SQ was not, in fact, fundamentally broken as a congestion signal - although
>one has to use it properly, as he indicates (above), and here:
>   Implementations of Source Quench entirely within the IP layer are usually
>   unsuccessful because IP lacks enough information to throttle a connection
>   properly.
>Making the point that it was the congestion response mechanism _in TCP_ that
>was lacking.
>And finally this:
>   All our switching nodes send ICMP Source Quench messages well before buffer
>   space is exhausted; they do not wait until it is necessary to drop a
>   message before sending an ICMP Source Quench.
>which is again, a _very early_ recognition of things like today's congestion
>bit, etc.
>Alas, I'm afraid we probably didn't pay as close attention to his work as we
>should have: John, if you're out there somewhere, my deepest apologies!
>	Noel