Unified transport layer support for data striping and host mobility

Data striping across multiple network interfaces and its applications to mobile environments was recently investigated (Phatak and Goff, 2002). Therein, a network-layer Internet protocol (IP)-in-IP encapsulation mechanism was proposed to aggregate the bandwidth of multiple network paths by striping a single transport layer [transmission control protocol (TCP)] connection across them. The analysis and experimental results from that study demonstrated fundamental limitations to TCPs performance in such scenarios. In this paper, we therefore propose a method of overcoming these limitations by striping data at the transport layer. For a proof-of-concept demonstration we use a substantially enhanced version of the stream control transmission protocol (SCTP). Our analytical results and experimental data illustrate that there are significant advantages to using a transport protocol with native support for the simultaneous use of multiple network interfaces, as opposed to stretching TCP to a point where it is no longer effective. This work naturally leads to another fundamental issue of end-to-end support for host mobility at the transport layer. Our analysis and results demonstrate that transport layer support for multiple network (IP) interfaces, together with the capability to dynamically add or delete IP addresses can yield the following advantages: higher bandwidth, load balancing, and increased fairness, enhanced reliability, and end-to-end support for host mobility. This is independent of the underlying network-layer and, hence, is applicable to static/wired, as well as wireless/ad hoc environments. The proposed protocol offers a unified solution to both data striping across multiple networks interfaces, as well as end-to-end mobility support.