End-to-end Performance During Mobile IP Handovers

Abstract

The traditional Internet and its protocols was designed for a static environment. Computers where located at fixed locations, and network connections where enabled physically trough wired cables. There where no means by which mobile workers could bring their computers around while maintaining network connection. Recent developments within portable computers such as laptops and PDAs, and wireless networking such as WLANs and GPRS have made it possible to have wireless networking wherever you are. The major drawback has been that since existing Internet protocols was designed for a wired and static network, full utilization of the wireless possibilities has not been feasable.

The main resistance has been in the fact that a network connection is identified by its two end-points, represented by the IP-address and the respective port number. When a computer changes network location or access technology, these values are changed, hence all current network connections must be shutdown and then reinitialized. This makes seamless roaming impossible. Mobile IP is an extension to the basic IP protocol which provides infrastructure and signaling to enable transparent mobility for terminals as the user is moving between networks

A critical phase in Mobile IP operation is the switch from one location or access technology to another. This process is known as a handover. A handover is not possible to perform in zero-time, hence some data packets in transmission are likely to get lost during the handover process.

In this thesis a performance evaluation of Mobile IP handover is presented. A dedicated testlab has been set up where the experiements have been preformed. The performance evaluation is based on both protocol and application levels, from actual packet loss and latency to user experience.

The performance evaluation has shown that traditional network applications performs quite well during Mobile IP handovers, while next generation applications, such as real-time services, are more exposed to experience quality degradation. An improvement to the transparent Mobile IP behaviour is proposed to enhance mobility perfomance also for such delay-sensitive applications.