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

[Michael Welzl]

i'd say bufferbloat is only one part of the problem. the other is and for a long time has been underutilization. it's long been the problem of congestion control - empty networks! but we're all waiting for stuff to happen as fast as possible...

meaningful aggregates are, for example, several flows that share the same bottleneck along their individual e2e path - they could be treated "together", rather than each probing the network on its own in one way or another


On Jul 17, 2013, at 5:04 PM, Barney Wolff <barney at databus.com> wrote:

> What are we talking about when we say "hop-by-hop" - the classic "don't
> send me anything on this link because I've got no buffer to receive it"
> or "don't send me anything on this flow because something downstream is
> pushing back"?  I thought these days bufferbloat is the problem, not buffer
> depletion.  What's an aggregate?
> 
> On Wed, Jul 17, 2013 at 09:36:08AM +0100, Jon Crowcroft wrote:
>> so i think the design decision to throw out all hop by hop flow
>> control was probably an error (not a disastrous one: as many people
>> have pointed out, it simplified early router design a lot to be
>> completely stateless - but you don't need to keep per-5-tuple based
>> e2e state to do hop by hop flow control if its on aggregates, right?)