A Multiple Tree Approach for Fault Tolerance in MPLS Networks
This paper presents a new approach to provide fault tolerance in MPLS multicast networks. MPLS has been used to provide faster forwarding; combining with multicasting it further supports applications with improved service. Fault tolerance is therefore imp
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Abstract. This paper presents a new approach to provide fault tolerance in MPLS multicast networks. MPLS has been used to provide faster forwarding; combining with multicasting it further supports applications with improved service. Fault tolerance is therefore important for such networks. Our strategy for fault tolerance is to divide and encode the traffic into multiple disjoint trees using a modified (k,n) Threshold Sharing scheme. Our scheme can reconstruct the original traffic from any k out of n trees available. Therefore, in the event of node/link failure(s) of any (n-k ) trees, our approach provides fault tolerance without introducing any recovery delay and packet loss. Moreover, our objective is also to minimize bandwidth utilization for protection purposes.
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Introduction
Many service providers use MPLS technology [5] as a solution to address the problems faced by conventional IP networks (speed, scalability, quality-of-service (QoS), and traffic engineering). Several applications like web services, video/audio on demand services, and teleconferencing consume a large amount of network bandwidth. Multicasting is a useful operation for supporting such applications. Using multicasting services, data can be sent from one or more sources to several receivers at the same time. The data is distributed with the use of a multicast tree structure. The establishment and maintenance of multicast trees make multicast routing more challenging than unicast routing. Several approaches have been proposed to deploy multicasting over MPLS networks. Moreover, many approaches have been proposed to employ MPLS based failure recovery methods in multicast trees [1,2,3,4]. Most of these approaches satisfy only some of the quality of service requirements. The existing schemes can be grouped in two categories: pre-planned and on-demand. On-demand approaches do not need to compute backup routes beforehand, the computational and maintenance cost is therefore low. However, these schemes usually experience longer recovery delay. In contrast, preplanned failure restoration predefines the backup routes, which introduces a large amount of computational and maintenance cost when there are large number of groups ongoing in the network. The big advantage of this type of fault tolerance is the much shorter recovery delay. In this paper we propose a novel approach for fault tolerance for MPLS T. Janowski and H. Mohanty (Eds.): ICDCIT 2007, LNCS 4882, pp. 197–202, 2007. c Springer-Verlag Berlin Heidelberg 2007
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S. Alouneh, A. Agarwal, and A. En-Nouaary
network based on multiple trees. Our scheme falls in the category of preplanned protection, and is based on the Threshold Sharing Scheme (TSS) [6]. We show that our scheme introduces no recovery delay and handles packet loss or node failure in up to (n-k ) trees.
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Proposed Algorithm
We use a modified version of TSS to suit MPLS networking requirements such as bandwidth. Threshold sharing scheme is a very well known concept used to provide security. However, the idea to use the threshold sha
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