REGIONAL AWARE FOREIGN AGENTS FOR MOBILE-IP

Abstract

The base IETF Mobile-IP [I] allows transparent routing of IP datagrams to mobile nodes in the Internet. However, the distant registration, handoff latency, and key management problems [2,3,4] among mobility agents hinders its widespread deployment. In this thesis, we propose a regional aware foreign agent (RAF A) [21] model that is interoperable with the base IETF Mobile-IP to solve the above problems. We also extend Mobile-IP to facilitate support of wireless Internet telephony and video conferencing. Our model allows handoff processing to be restricted to the vicinity of a mobile node, and reduces the number of trusted entities in the network to minimise the key management problem. The proposed enhanced local handoff protocol for the mobile node as an extension to our regional aware foreign agent model also reduces the handoff latency due to the handoff operational procedure of Mobile-IP. It allows smooth handoff to support even the stringent demands of interactive video or audio applications. In our model, we introduce two new entities - regional aware foreign agent and local foreign agent. Through a registration process between the regional aware foreign agent and the local foreign agents, a home agent has incomplete knowledge the mobile node's true point of attachment. It enables the mobile node to inform only the local mobility agent each time it moves compared to Mobile-IP which requires it to inform the home agent that may be far away. The immediate registration mechanism combined with the new simultaneous bindings at the regional aware foreign agent for local registration also results in a low handoff latency leading to a significant improvement in TCP throughput during handoff. We present our experience of a practical implementation of the proposed regional aware foreign agent model using Linux's [5,6] kernel programming. We also present experimental results to compare the performance of the regional aware foreign agent model and the base Mobile-IP protocol. We show that the regional aware foreign agent model not only solves the problems of the base protocol, it also provides much better throughput performance during handoff than the base protocol, and is able to extend Mobile-IP to facilitate support of wireless Internet telephony and video conferencing applications which demand little network latency.