  RED (Random Early Detection) has been suggested when multiple TCP sessions
are multiplexed through a bottleneck buffer. The idea is to detect congestion
before the buffer overflows by dropping or marking packets with a probability
that increases with the queue length. The objectives are reduced packet loss,
higher throughput, reduced delay and reduced delay variation achieved through
an equitable distribution of packet loss and reduced synchronization. Baccelli,
McDonald and Reynier [Performance Evaluation 11 (2002) 77--97] have proposed a
fluid model for multiple TCP connections in the congestion avoidance regime
multiplexed through a bottleneck buffer implementing RED. The window sizes of
each TCP session evolve like independent dynamical systems coupled by the queue
length at the buffer. The key idea in [Performance Evaluation 11 (2002) 77--97]
is to consider the histogram of window sizes as a random measure coupled with
the queue. Here we prove the conjecture made in [Performance Evaluation 11
(2002) 77--97] that, as the number of connections tends to infinity, this
system converges to a deterministic mean-field limit comprising the window size
density coupled with a deterministic queue.
