(no subject)

This paper attempts to solve the issue of network congestion using a
congestion avoidance scheme requiring explicit feedback from routers
within the network. By piggybacking congestion data onto existing
packets, using a single bit, they are able to provide congestion
feedback without introducing any new packets into the network.

The strength of their solution is that it allows "congestion
avoidance", whereby anti-congestion actions can hopefully be taken
before any packets are lost and that it does so without introducing
additional congestion-causing packets. The weakness is that it
requires modifications to the infrastructure of the internet, in that
every router must be modified or replaced to support this technique
effectively. There is no means for a binary-feedback-supporting
router to detect congestion within a non-supporting router.

Were we to design the internet today, it might require some form of
router-level congestion sensing. This would not be a violation of
the end-to-end principle, in that congestion detection and control
would still be provided at the ends, but using information provided
by the middle to assist in this process. Instead, we are faced with
a chicken-or-egg sort of problem: until the network is fully
supporting of router-level congestion feedback, a router-independent
congestion control mechanism is required, and as long as a router-
independent congestion control mechanism is in place, there is little
motivation to support router-level congestion feedback.
Received on Mon Sep 25 2006 - 21:10:24 EDT