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

Mark Handley m.handley at cs.ucl.ac.uk
Wed Jul 17 03:52:56 PDT 2013

On Wed, Jul 17, 2013, at 01:36 AM, Jon Crowcroft wrote:
> so most systems in the world do hop by hop as well as end to end
> e.g. 
> transportation systems  (traffic lights, stacks of planes, semaphores to
> control trains entry/exit from track sections etc etc)
> power systems (elec ant gas)
> water systems (valves etc)
> eco-systems (food chains/feast/famine etc)
> political systems (you switch from feudal to democract, btut you still
> have periodic elections - you switch from city states to countries,
> but still have border and immigration/emigration controls...:)
> so why do we think comms should be different?

Because it's not politically acceptable to drop planes when air traffic
control gets congested? Dropping a packet that has not yet consumed any
resource at the bottleneck does not cost anything.

In fact it does cost latency, but it seems to me that keeping latency
low is the only strong reason for wanting any form of in-network flow

- Mark

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