Self-Stabilizing Computation and Preservation of Knowledge of Neighbor Clusters

Abstract

Abstract-The area of self-stabilization in large scale networks has been received increasing attention among researchers, since self-stabilization provides a foundation for self-properties, including self-healing, self-organizing and self-adaptive. This paper makes contributions in two areas. First, we describe a new extended approach of selfstabilization, called self-stabilization with service guarantee. Second, we propose a self-stabilizing protocol computing and preserving the knowledge of neighbor clusters, called CNK. A cluster-head maintains about each neighbor cluster: the identity of its head, paths leading to it, and the list of members. The most interesting property of CNK is the service guarantee during the stabilization phase. CNK quickly provides, in at most 4 rounds, the following minimal useful service: "each cluster-head knows valid paths leading to heads of all its neighbor clusters". CNK protocol preserves the minimal service despite changes in the clustering structure (creation of new clusters, restructuring or crumbling of existing clusters). The knowledge of neighbor clusters is thus highly available. This knowledge is enough to allow the continuity functioning of hierarchical protocols as hierarchical routing protocols.

From Self- to Self-stabilizing with Service Guarantee 1-hop Weight-Based Clustering

“…Ready allows just the control of T P actions by UHP in order to ensure the service guarantee of UHP protocol. For example, UHP can be the knowledge of neighbor clusters protocol proposed in [18], where the minimal service is "the permanent availability of paths leading to the head of each neighbor cluster". Ready is thus an interface that enables the implantation of self-stabilizing with service guarantee protocols on the top of T P protocol, as hierarchical routing protocols.…”

“…To overcome these drawbacks, the paradigm selfstabilization with service guarantee has been recently introduced in [17,20,18]. A protocol P is self-stabilizing with service guarantee if: (1) P is self-stabilizing; (2) from an arbitrary configuration, P quickly reaches a safe configuration, where a safety property is satisfied, so a minimal service is provided; (3) the safety property (minimal service) holds during progress of P towards the optimum service (i.e., during stabilization despite actions of P) and, (4) the safety property (minimal service) is also maintained despite the occurrences of some specific external disruptions, called highly tolerated disruptions, denoted HT D.…”

“…However, external disruptions are not handled in safe convergence. Let us study the self-stabilizing with service guarantee protocol [18] building the knowledge of 1-hop neighbor clusters. The stabilization time of this protocol is 4 rounds as the time to reach a safe configuration.…”

“…In this case, the safe convergence contributes nothing compared to the self-stabilization (they become equivalents). The main specifity of [18] is the maintain of safety property in spite of disruptions made by clustering protocol (i.e., reconstruction of clusters). A super-stabilizing protocol guarantees that (1) starting from a legitimate configuration, a safety property is preserved after only one specific topology change (of a set HT D), and (2) the safety property is maintained during recovering to a legitimate configuration assuming that no more topology change occurs during stabilization phase.…”