Receive buffer blocking in concurrent multipath transfer

Previously, we studied the performance of concurrent multipath transfer using SCTP multihoming (CMT) under the assumption of an infinite receive buffer (rbuf). Here, we study CMT performance when a sender is constrained by the rbuf. We demonstrate using simulation that if two paths are used for CMT, the lower quality (i.e., higher loss rate) path degrades overall throughput of an rbuf-constrained CMT association by blocking the rbuf. We demonstrate that a wise retransmission policy can alleviate some of the throughput degradation by reducing the rbuf blocking problem. We present and discuss CMT performance using several retransmission policies and constrained rbuf values of 16 KB, 32 KB, 64 KB, 128 KB, and 256 KB. While rbuf blocking cannot be eliminated, it can be reduced by choice of retransmission policy - a facility available to only the transport layer.