Evaluation of Router Implementations for Explicit Congestion Control Schemes

— Explicit congestion control schemes use router feedback to overcome limitations of the standard mechanisms of the Transmission Control Protocol (TCP). These approaches require additional packet processing in every router and therefore raise the question whether, and how, this can be achieved in high-speed routers. This paper investigates the realization complexity of these router functions of two such schemes, the TCP Quick-Start extension and the Explicit Control Protocol (XCP). Our focus lies on the implementation using a network processor. We show that synchronization issues among parallel processing entities have to be considered, and that this affects the router performance. We develop and compare different synchronization mechanisms for highly parallel packet processing. Our prototype implementation on an Intel IXP network processor allows to quantify the impact on throughput and delay caused by the additional packet processing in the fast path. The measurements reveal that Q...

• Type: Journal
• Year: 2010
• Where: JCM
• Authors: Simon Hauger, Michael Scharf, Jochen Kögel, Chawapong Suriyajan
• Keywords: Additional Packet, Control Protocol, JCM 2010, Router