Balancing loads on SONET rings

Abstract

Recently, restoration techniques in telecommunication networks are developed to implement a survivable network for service assurance. Restoration techniques that use dedicated facilities for protection include automatic protection, dual homing and Self Healing Rings (SHR). SHR is a ring network that provides redundant bandwidth in which disrupted services can be automatically restored following network failures. SHR is one of the most intriguing schemes which provide survivability for telecommunication networks. To design a cost effective SONET ring it is necessary to consider load balancing problems by which the link capacity is determined. In chapter 2, we consider the load balancing problem in SONET ring when demand splitting is allowed only by integer. A bounded approximation to the optimal solution is presented and proved by employing the arc-demand matrix which represents the amount of demand routed on each arc. A very efficient algorithm is provided which always satisfies the condition at termination. The algorithm iteratively decreases the maximum load by considering counter-clockwise routing of a demand which passes through the arc with maximum load. Justification of the algorithm is also provided. The load balancing problem in SONET ring when demand splitting is not allowed is considered in chapter 3. It is proven to be NP-complete. An algorithm is presented and compared to dual-ascent approach which has good computational results than other heuristics.