TCP-Real: receiver-oriented congestion control

We introduce a receiver-oriented approach to congestion control, demonstrated by an experimental protocol, TCPReal. The protocol allows for a measurement-based transmission strategy, which complements the ‘‘blind’’ increase/ decrease window adjustments. Owing to its design, the protocol displays an inherent property to produce comprehensive dynamics in heterogeneous environments with wired or wireless networks and delay-sensitive or -tolerant applications. TCP-Real controls congestion as standard TCP does. However, its receiver-oriented nature and its ‘‘wave’’ communication pattern allow for two amending mechanisms: (i) congestion avoidance, which reduces unnecessary transmission gaps that hurt the performance of time-constrained applications, and (ii) advanced error detection and classification, which designates recovery tactics responsive to the nature of the errors, thereby enhancing the protocol performance over wireless links or asymmetric paths. We detail the protocol mechanisms and specification and we report extensively on the comparative fairness and efficiency evaluation of standard TCP, TCP-Real, and TCP-friendly protocols for both delay-tolerant and -sensitive applications and in both wired and wireless networks. 2002 Elsevier Science B.V. All rights reserved.