On the Performance of TCP Splicing for URL-Aware Redirection

This paper describes the design, implementation and performance of a layer-7 switch which supports URL-aware redirection of HTTP traffic. Currently, there are several vendors who are beginning to announce the availability of such switches in the market, but little or no implementation and performance information is available. We discuss design issues pertaining to such switches through a prototype implementation of a URL-aware switch in the Linux kernel, and analyze the performance of our implementation. We investigate the use of TCP splicing as a mechanism for improving the performance of the switch; we explore whether TCP splicing will benefit URL-aware redirection even though HTTP connections, on average, are short-lived and transfer small amounts of data. Results from our implementation show that TCP splicing does improve the performance of URL-aware switches that handle short-lived HTTP connections. Our results also re-affirm earlier findings that TCP splicing substantially improves the performance of any application-layer proxy when large amounts of data are transferred through the splice.