The effect of network hierarchy structure on performance of ATM PNNI hierarchical routing

Networks deploying hierarchical routine are recursively partitioned into sub-networks that oo not reveal the full details of their internal structure outside their domains. Instead, an aggregated view of certain parameters that are associated with traversal within such sub-networks between their border nodes in advertised. The ATM PNNI standard and the Internei Nimrod architecture both adopt this approach for routing. This paper studies the effectiveness of ATM hierarchical routing protocols on networks with different hierarchical structures by simulation. Our study shows that., in general, the hierarchical source routing performs well compared to the global routing strategy which imposes no hierarchy, while utilizing less storage and communication overhead. For certain networks and topologies, the hierarchical routing performs better than the global routing. Different hierarchies imposed on the same topologies have significantly different performance on the throughput and routing delay. This suggests the necessity of studying Me hierarchy design far communication networks using hierarchical routing.