[e2e] Does congestion control belong to The Transport Layer?

[David P. Reed]

At 03:42 PM 4/25/2004, Cannara wrote:
>If, as you suggest, the network incorprated management of its own congestion,
>even if only at ends, but with good information from the interior, that would
>be better.  That would indeed be an example of a network "service" -- datagram
>carriage with congestion management.

Doing this at the datagram level means throwing away all the information 
about the relationships between datagrams that is known at the application 
level.   For example, some datagrams may be controlling other flows (such 
as datagrams that are used to tell the other end to stop sending!)

The whole reason that congestion control is end-to-end is because the 
ultimate causes of traffic are end-point algorithms, and it's those 
algorithms (and their human users) that need to adapt.   The multiplexing 
of independent streams happens at each OS's applcation API - so 
implementing ths "service" would have to reach back at least to that 
definition of the entry point into the network.

Pretending that all traffic on the network consists of infinite-sized file 
transfers is intellectually ignorant.  It's about as informed as thinking 
that a 1/4 mile drag race in a "funny car" is an effective simulation of 
commuter traffic.