MOMBASA: Mobility Support – A Multicast-based Approach

In general IP multicast supports location-independent addressing and routing for a group of hosts. This ability is similar to the requirement for mobility support in IP-based networks though in a different context. MOMBASA stands for “MObility support – a Multicast BASed Approach”. It is intended to utilise multicast in order to support network level mobility. The basic mechanism of a multicast-based handover can be composed of a multicast joinand leave-operation of the new and old multicast router, respectively. Additionally to the basic mechanism, MOMBASA investigates extended multicast functionalities which improves the handover in terms of the handover latency, the management of the multicast group and adaptation of the multicast data traffic to the wireless transmission capabilities. In particular the extended multicast functionalities are useful for vertical handover. Unfortunately today’s IP multicast suffers from scalability problems and is not generally available. Nevertheless it is commonly expected that the future Internet will provide an optimised multicast. MOMBASA works out the requirements of handover on future multicast protocols and investigates alternate IP-style multicast protocols. As a first approach a multicast protocol is considered which realises a dynamic multipoint-to-multipoint communication in switched networks. An experimental handover testbed is set up which proofs the basic approach and provides extended multicast functionalities. The testbed is described and performance results are given. Other IP-style multicast protocol will be investigated in further steps.