Corruption and reordering robust TCP-friendly rate control

Abstract

TCP-Friendly Rate Control (TFRC) mechanism was introduced for regulated multimedia streaming over the Internet. TFRC unnecessarily reduces the application sending rate in wired network scenarios with packet reordering. TFRC also gives poor performance over wireless access networks. The poor performance of TFRC on paths that reorder packets and on wireless access networks can be attributed to its inability to differentiate packet losses due to congestion from other network conditions like packet reordering and corruption. We first examine the performance of TFRC over wireless network with UDP-lite that reduces packet drops over the wireless link. Next we propose few methods to make TFRC robust in packet reordering scenarios and evaluate the performance of TFRC with these schemes incorporated. Then we suggest a modification to TFRC from being loss-based to ECN-marking based. ECN-marking based TFRC performs rate regulation according to actual network congestion experienced and is robust to packet reordering and corruption in the network. We provide the results of our extensive experiments on a network testbed for various scenarios with packet corruption and/or packet reordering. We also observe the impact of ECN-based TFRC on concurrent TCP flows.