Evaluation of replacement protocols and modifications to TCP to enhance ASC Wide Area Network performance.

Abstract

Historically, TCP/IP has been the protocol suite used to transfer data throughout the Advanced Simulation and Computing (ASC) community. However, TCP was developed many years ago for an environment very different from the ASC Wide Area Network (WAN) of today. There have been numerous publications that hint of better performance if modifications were made to the TCP algorithms or a different protocol was used to transfer data across a high bandwidth, high delay WAN. Since Sandia National Laboratories wants to maximize the ASC WAN performance to support the Thor's Hammer supercomputer, there is strong interest in evaluating modifications to the TCP protocol and in evaluating alternatives to TCP, such as SCTP, to determine if they provide improved performance. Therefore, the goal of this project is to test, evaluate, compare, and report protocol technologies that enhance the performance of the ASC WAN.

Network protocol changes can improve DisCom WAN performance : evaluating TCP modifications and SCTP in the ASC tri-lab environment.

“…The figures below, extracted from previous works [1,2], show that the increased (best case of 12%-to 5%) from standard TCP currently does not warrant the modification to the TCP stack. …”

“…However, none of these proposals has been adopted into the main stream TCP implementations. A laboratory version of the DisCom WAN was created so that Sandia could investigate these modifications, evaluate them in great detail and report their performance [1,2]. In addition to modifications to TCP a new protocol, the Stream Control Transmission Protocol (SCTP), had been developed and become part of the Linux operating system environment.…”