Fault-Tolerant and Scalable TCP Splice and Web Server Architecture ; CU-CS-1003-06

This paper proposes three enhancements to the TCP splicing mechanism: (1) Enable the same TCP connection to be simultaneously spliced through multiple machines for better scalability; (2) Make a spliced connection faulttolerant to proxy failures; and (3) Provide flexibility of splitting the splicing functionality between a proxy and a backend server for further increasing the scalability of a web server system. A web server architecture based on this enhanced TCP splicing is proposed. This architecture provides a highly scalable, seamless service to the users with minimal disruption during server failures. In addition to the traditional web services in which users download webpages, multimedia files and other types of data from a web server, the proposed architecture supports newly emerging web services that are highly interactive, and involve relatively longer, stateful client server sessions. A prototype of this architecture has been implemented as a Linux 2.6 kernel module, and the paper presents important performance results.