Multipath Routing Compatible Congestion Control

The evolution of network applications poses significant challenges to network service provisioning. Multipath routing and packet spraying techniques have become crucial in networks. TCP performance declines sharply on multipath setups where significant packet reordering occurs, as unordered transmissions are misinterpreted as packet loss and congestion signals. We propose the Multipath Routing Compatible (MPRC) congestion control, which utilizes the delay-sensitive Fast Retransmission Timeout (FastRTO) to decouple reordering from loss signals and enhance loss detection. This modification optimizes congestion window adjustments in multipath environments and handles packet reordering effectively, ensuring stable TCP throughput across multipath settings. Our algorithm was implemented on the NS-3 simulator platform and compared with other congestion control algorithms across various network topologies, in both single-path and multipath routing scenarios. The results demonstrate that MPRC can handle both sporadic and persistent packet reordering, ensuring steady throughput in multipath routing environments while maintaining compatibility and fairness in bandwidth competition, which paves the way for efficient congestion control adopting multi-path routing networks.