Virtual trees routing protocol for a wireless ATM LAN

This paper presents a new routing algorithm for a wireless ATM (asynchronous transfer mode) LAN (local area network). The LAN combines positive aspects of connection-oriented and datagram communications schemes in its usage of the ATM VP/VC (virtual path/virtual channel) concept. In this scheme, a set of VPI (virtual path identifier) trees, rooted at each node in the LAN, are preestablished. This has the effect of emulating “connectionless” networking which simplifies handoffs and other mobility management tasks. Given that the VPI sink trees are preestablished, there is a need for a procedure to compute and update the routes of these VPI trees with changing conditions in the LAN. We first propose an off-line procedure to compute the initial VPI trees. Since traffic conditions are likely to change rapidly in mobile networks, we propose a distributed scheme called VTRP (virtual trees routing protocol) to dynamically update the routes of VPI trees in response to repeated congestion and/or topological changes in the network