Enhancing TCP Performance in IP Fast Reroute
Source: University of Hohenheim
IP Fast ReRoute (IPFRR) mechanisms are efficient in providing protection against link or router failure by invoking locally determined backup paths. But in the presence of a transient network failure, the path oscillates between backup and original paths, causing frequent packet out-of-order arrivals at a TCP receiver. DUPlicate ACKnowledgments (DUP-ACKs) generated by the receiver will then trigger unnecessary TCP congestion control at the sender. In this paper, the authors propose a novel yet simple algorithm called Duplicate Acknowledgement Suppression (DAS) for enhancing the TCP performance in the presence of IPFRR. DAS only requires a minor modification to the TCP implementation at the receiver side while leaving the sender intact.