[e2e] Why was hop by hop flow control eventually abandonded?

Baohua Yang yangbaohua at gmail.com
Wed Jul 17 18:14:34 PDT 2013


agree.
switch is hard to support compliacted states and logics, due to the
performance requirement and the hardware limitation.
however, it would be a worthy idea in SDN, where more flexibility can
be provided by the stateful controller.

On 7/16/13, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
>     > From: Detlef Bosau <detlef.bosau at web.de>
>
>     > the decision to abandon hop by hop flow control
>     > ...
>     > Does anyone happen to know, whether this was decision for a concrete
>     > reason and the rational behind it? Or did this "simply happen"?
>
> Probably the internet-history list is a better place to ask this?
>
> I don't know for sure, but having arrived on the scene shortly thereafter,
> and knowing intimately what packet switches were like then, my _guess_
> is that it had to do with state.
>
> It seems to me that to be able to do hop-by-hop flow control, you have to
> have some state in the switches, yes? (I can't see a way to do it without.)
>
> And in a 'smallish' network, like the ARPANET, it's reasonable to have that
> state. But when you're talking about (potentially) a much bigger network,
> as
> the Internet even then was planned to be, the amount of state potentially
> needed would quite likely have been too much for the switches of the day.
>
> 	Noel
>

-- 
Sent from my mobile device

Best wishes!
Baohua


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