An improved scheme for self-healing in ATM networks

Broadband networks based on ATM technology can carry a large volume of data and can support diverse services Like audio, video, and data uniformly. Th e reliability and availability levels provided by such networks should be v ery high. Self-healing is an elegant concept in this direction to provide h ighly reliable networks. A self-healing network can detect failures such as link/node failures and reroute the failed connections automatically using distributed control mechanisms. In this paper, we consider link and node fa ilures including the VP terminating nodes unlike Kawamura and Tokizawa (Sel f-healing in ATM networks based on virtual path concept, IEEE Journal on Se lected Areas in Communications 12 (1) (1994) 120-127). We present here an i mproved scheme for self-healing in ATM networks based on the concept of bac kup VPs. The problems we address are. (i) self-healing scheme; and (ii) bac kup VP routing. Two issues are addressed in the self-healing scheme: (i) ba ckup VP activation protocol; and (ii) dynamic backup VP routing. We propose a new backup VP activation protocol which uses a VC packing strategy which allows the fast and prioritized restoration of critical VCs that were carr ied by failed VPs. We also propose a distributed dynamic backup VP routing algorithm which reduces the resource contention that may occur when multipl e source-destination pairs contend for the routes simultaneously. The objec tive of the backup VP routing problem is to find a backup VP for each of th e working VPs so that the cost of providing the backup is minimized. We pro pose a heuristic based solution for the backup VP routing problem using the concept of minimum cost shortest paths. We conducted simulation experiment s to evaluate the performance of the proposed schemes. The results show tha t the proposed schemes are effective. Comparison of the results with these of the earlier schemes (R. Kawamura, I. Tokizawa, Self-healing in ATM netwo rks based on virtual path concept, IEEE Journal on Selected Areas in Commun ications 12 (1) (1993) 120-127; C.J. Hou, Design of a fast restoration mech anism for virtual path-based ATM networks, Proceedings of IEEE INFOCOM'97, Kobe, Japan, April 1997) shows that the proposed schemes perform better. (C ) 1999 Elsevier Science B.V. All rights reserved.