A Novel Dynamic Fault Restoration Mechanism Using a Multiple Ring Approach in WDM Mesh Networks

Abstract

This work describes a distributed fault restoration algorithm, called the Dynamic Multiple Ring Algorithm (DMRA), for application in WDM mesh networks. This study explores the choice of restoration paths and the assignment of fault-tolerant bandwidth when a link, node, or channel failure occurs according to the change in traffic load, number of nodes, and transmission delay including propagation and switching delays. Accordingly, the primary aim of this work is to use networking segments near faults to share the restoration load throughout a mesh network. Each node searches for restoration paths in their near environment using the proposed DMRA. Nodes use distributed control to search for neighboring nodes and to establish the relationship between them to build numerous logical rings. Nodes can also locate faults in the logical rings. These rings establish the restoration paths. The traffic load over failed links or nodes can be diverted to other paths in the networking segments. The cost of the restoration paths is computed at each node based on both the current capacity and the transmission delay. The selected restoration paths are suitable transmission routes in the network neighborhood. Hence, restoration paths can be identified and wavelength assigned quickly according to network bandwidth and traffic load. Simulation results reveal that the proposed method works extremely quickly and has a high success rate. Consequently, it is very useful for applications in real WDM networks, where the status varies from minute to minute.

Guaranteed Quality of Recovery in WDM Mesh Networks

“…If a route is completely established, all nodes along the working and backup paths will obtain the path information, and then the path information will be stored in the database called Recovery Table in each node. Moreover, the GQoR mechanism will be further explained in this paper, since only the concepts are addressed in the authors' previous works such as implementation of distributed control for overlapped and non-overlapped segment protection algorithms (OSP and NOSP) [12] and Dynamic Multiple Ring Algorithm (DMRA) [13]. The proposed GQoR mechanism which is divided into four levels is shown in Table 1, and the definition of GQoR levels is addressed in details as follows.…”

“…The benefit of the NOSP method is simple and economic, but it is less protection ability if a beginning node of any backup path fails in the working path [16]. not apply to the pre-calculated protection path, instead the restoration mechanism of DMRA [13] to recover from the failure. For brief address of DMRA, the nodes can use distributed control to find neighbouring nodes and establish relationships between nodes to construct several logical rings.…”

“…Figure 8 shows the flowchart of subroutine -execute Segment Restoration. In this subroutine, the DMRA mechanism [13] is used to find the adaptive segment restoration path. If some level 4 paths occupy the resources, the subroutine will try to tear down these paths and find the restoration path again.…”

“…Therefore, the GQoR mechanism jumps to the level 3 Segment Restoration mechanism to avoid this problem. In level 3, the DMRA [13] algorithm can immediately build the new network topology and find an adaptive restoration path. For level 4 Reroute, a new route and the backup paths will be created if the resources are enough.…”

A novel dynamic Multiple Ring-based Local Restoration for point-to-multipoint multicast traffic in WDM mesh networks

“…The p-cycle is a well-known ring-based solution, but it is a NP-hard problem to find one minimum cost ring to cover all multicast member nodes and it is not scalable. An approximate method, the dynamic multiple ring approach (DMRA) in our previous work [15][16][17], uses multiple rings to recover failures for unicast traffic. The advantages of multiple rings is to search for restoration path dynamically and scalable to any sizes of network topology.…”