Parallel TCP Sockets: Simple Model, . . .

We consider a simple model of parallel TCP connections defined as follows. There are N connections competing for a bottleneck of fixed capacity. Each connection is assumed to increase its send rate linearly in time in absence of congestion indication and otherwise decreases its rate to a fraction β of the current send rate. Whenever aggregate send rate of the connections hits the link capacity, a single connection is signalled a congestion indication. Under the prevailing assumptions, and assuming only in addition a mild stability condition, we obtain that the throughput is the factor of the link capacity, 1 − 1/(1 + const N), with const =(1 + β)/(1 − β). This result appears to be previously unknown; despite simplicity of its final form, it is not immediate. The result is of practical importance as it elucidates the throughpu