Impact of Gateway Discovery on Tcp-connections in Manets

Mobile ad hoc networks (MANET) can be formed in scenarios where the access to the Internet is demanded. Most of the Internet traffic could be supported by TCP traffic (e.g. HTTP traffic). However, TCP technology needs to be adapted to cope with the different features of the wireless (the MANET node) and the wired (Internet host) mediums. The functionalities for this adaptation could be implemented in the Gateway as it is proposed by TCP-GAP. This new version of TCP is specially designed for MANETs connected to the Internet. Although the evaluation results seem promising, this new technology has been exclusively evaluated in static scenarios. This kind of scenarios represents a simplification of real MANETs where terminals can freely move. Furthermore, static scenarios do not deal with the problem of acquiring or updating the route to the Gateway which connects to the Internet. Our paper focuses on the evaluation of TCP-GAP in mobile environments. In particular, it analyzes the impact of the gateway discovery procedure on the TCP performance by means of simulations. As the simulations show, the gateway discovery procedures, by which mobile nodes update the route to the Gateway, have a significant effect on the asymmetry of the TCP-flows.