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
we show by simulation, that it can disproportionately
overload lower-bandwidth links and, due to its
inherent redundancy, can generate considerable
computational overhead due to the processing of redundant
topology updates. To address these issues, we introduce
the Hybrid Spanning Tree algorithm,
a spanning tree-based
topology distribution mechanism that has low
computational maintenance and can support policy that
restricts topology distribution control traffic from being
carried over lower-bandwidth links. Unlike other
spanning tree proposals, the Hybrid Spanning Tree algorithm
provides a simple and practical migration path to
smoothly transition PNNI nodes executing the flooding
algorithm to that of the Hybrid Spanning Tree algorithm.

By: Erol Basturk, Paul Stirpe

Published in: RC20922 in 1997


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