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

[ih] FC vs CC Re: [e2e] Fwd: Re: Once again buffer bloat and CC. Re: A Cute Story. Or: How to talk completely at cross purposes. Re: When was Go Back N adopted by TCP

    > From: Vint Cerf <vint at google.com>

    > Donald Davies had the idea of an isarithmic network: a fixed number of
    > packets in the network at all times. Issues however included getting
    > "empty packets" to places with data to send. 

Yes - an interesing approach, but I'm not sure it's workable - especially
in a large internet. 

The paper is interesting though because it does use the terms "flow control"
and "congestion control" in pretty much their modern meanings:

  This so-called "isarithmic" method of congestion control supplements and
  does not replace end-to-end flow control.

And as Brian pointed out, you can clearly see that his earlier work in road
networks has influenced his understanding, e.g.:

  By analogy with road traffic, congestion can be expected to begin at one
  point in the network and spread as the queues fill and links between
  switching centres are blocked.

It's really interesting to see how many times various people looked at the
congestion control issue, and their results didn't really catch on widely,
until we all finally 'got the message' after the Internet congestive
collapses, and Van's work.

Speaking of PUP, it's interesting to see what they did for congestion
control: looking in the seminal "PUP: An Internetwork Architecture" (July
1979) they have several sections on congestion control ("2.8. Flow control
and congestion control", "5.2. Congestion control and utilization of
low-bandwidth channels"), and clearly differentiate between flow and
congestion control.

However, they don't (at least, in that document) give specifics on their
congestion control algorithms in the hosts, just indicate that they use their
version of Source Quench as a congestion signal, with only a general gloss on
how it's used:

  The source process can use this information to modify its transmission
  strategies-for example, to reduce its offered load .. and thereby help to
  relieve the congestion.

Anyone know anything more about congestion control algorithms in PUP?