PNNI clustering under node mobility in ATM networks

This paper examines the issue of PNNI routing in the context of mobile ATM networks. For reasons of efficiency, the PNNI protocol has been invented in order to aggregate ATM switches into groups. In the context of PNNI, the formation of peer groups is an important issue. This paper presents an aggregation algorithm that produces an optimal node group arrangement by taking into consideration the physical constraints such as node distance, node affinity and maximum peer group size. Furthermore, the issue of node mobility and its impact on the peer group assignment are considered. As the position of nodes changes with time, the network hierarchy may no longer be optimal and, therefore, may need rearrangement. The focus of this paper is to develop the criteria used for deciding when to perform network rearrangements. A metric is introduced for assessing the relative difference between the current node assignment and the optimal one. The impact of the various parameters is investigated by both analytical and simulation means.