On the design and performance of kernel-level TCP connection endpoint migration in cluster-based servers

The TCP connection endpoint migration allows arbitrary server-side connection endpoint assignments to server nodes in cluster-based servers. The mechanism is client-transparent and supports back-end level request dispatching. It has been implemented in the Linux kernel and can be used as part of a policy-based software architecture for request distribution. We show that the TCP connection end-point migration can be successfully used for request distribution in cluster-based Web servers, both for persistent and non-persistent HTTP connections. We present locality-aware policies using TCP connection migration that outperform Round Robin by factors as high as 2.79 in terms of the average response time for certain classes of requests.