Performance Enhancement for TCP/IP on Wireless Links
J. Scott Stadler, Jay Gelman, Jeffery Howard · Kluwer Academic Publishers eBooks · 2005
The TCP/IP protocol suite that forms the basis of the Internet was designed to operate over an extremely large range of environments. Despite this robustness, degraded levels of performance may be experienced when the assumptions inherent in its algorithms are violated. For instance, the potentially high BER of a terrestrial wireless link or the high delay-bandwidth product of a satellite link result in a situation in which the link is not efficiently utilized and the TCP/IP performance (as perceived by an interactive user) may be poor.This paper will identify the reasons for the reduced levels of performance and describe two techniques for dramatically improving the performance (efficiency and perceived QoS) of TCP/IP in a wireless environment. The selected techniques possess the desirable properties of transparency, scalability, and backward compatibility. The first is a link layer protocol that uses a combination of fragmentation coupled with selective repeat ARQ at the link layer to improve TCP/IP performance. The second is a split connection approach that eliminates TCP from the wireless segment of the network. This allows protocols developed specifically for the wireless environment of interest to be used on the wireless segment of the network path. Both of these techniques have been prototyped and tested on the Wireless Networking Test-bed at Lincoln Laboratory. Test results show that nearly optimal performance may be obtained for many scenarios of interest.