A Hybrid Spanning Tree algorithm for efficient topology distribution in PNNI

The ATM Forum's PNNI standard specifies a flooding mechanism to distribute topological state information amongst nodes participating in a PNNI network . While the flooding mechanism provides robust topology distribution, we sh ow by simulation that it can disproportionately overload lower-bandwidth li nks and, due to its inherent redundancy, can generate considerable computat ional overhead due to the processing of redundant topology updates. To addr ess these issues, we introduce the Hybrid Spanning Tree algorithm, a spanni ng tree-based topology distribution mechanism that has low computational ma intenance and can support policy that restricts topology distribution contr ol traffic from being carried over lower-bandwidth links. Unlike other span ning tree proposals, the Hybrid Spanning Tree algorithm provides a simple a nd practical migration path to smoothly transition PNNI nodes executing the flooding algorithm to those of the Hybrid Spanning Tree algorithm.