BFC heuristic approach for constraint-based path selection in QoS routing

In DiffServ networks QoS-based routing for only one QoS measure (e.g. constrained bandwidth) is known as the restricted shortest path (RSP) problem. It can be treated as the minimum cost network flow problem in the multicommodity single source multiple destination network. For constrained-based path selection in QoS routing with N quality of service levels in function to serve predicted traffic demands, an efficient heuristic algorithm is being developed. The algorithm approach is of BFH (backward-forward heuristic) type. The optimal flow theory enables separation of these extreme flows which can be a part of an optimal expansion solution from those which cannot be. Algorithm is compared with algorithm based on exact approach. In all numerical test-examples the best possible result is achieved, but with significant reduction of complexity and computation savings.