A design of self-healing ATM networks based on backup virtual paths

Broadband network will support a variety of services such as voice, video, data and image with different traffic characteristics and different qualities of service in integrated environment. Asynchronous transfer mode (ATM) network techniques have been actively studied with the goal of realizing B-ISDN. ATM network will provide the infrastructure for B-ISDN and offer the benefit of enhanced flexibility when the virtual path (VP) concept is adopted. One of the most important issues in B-ISDN is the increased level of network survivability. The backup VP scheme prepares a preassigned backup VP before a failure occurs. A backup VP can be assigned between any pair of nodes on a VP route. The backup route is link disjoint from the original path to avoid the simultaneous failure of both the original and the backup VP. In this paper, a self-healing VP network design is considered to find the configuration of the backup VP such that the cost of required spare capacity is minimized. We propose a design of self-healing ATM virtual path (VP) networks based on backup VP. The backup VP is a preassigned virtual path to restore the traffic after a network failure. It is known that the self-healing scheme based on the backup VP is simple, fast and easy to implement. Given a set of bandwidth requirements and original routes for target demands, the design is to find the backup route of each traffic demand such that the cost of total spare bandwidth, which is required for each physical link to restore the services, is minimized. The problem is formulated as an integer linear program. Based on the property that a common backup VP of any two distinct traffic demands saves the required bandwidth, an initial and two improvement heuristics are proposed. Computational experiments show that the proposed procedure provides solutions the gap of which are less than 11% compared to optimal solutions.