Partial optimization method of topology aggregation for hierarchical QoS routing

To support various services in the current Internet, QoS routing was proposed. QoS routing finds a path to meet the requested QoS specification for a user, reserves network resource, thereby guaranteeing the QoS for the user. Much work has been done for QoS routing in an autonomous system (AS) to make it feasible in large networks. For a large network, hierarchical QoS routing is promising candidate because it is scalable. It divides the network into several levels and routing is performed at each level. The most important factor in hierarchical QoS routing is topology aggregation, which makes lower level nodes send simplified and aggregated network topology information to upper level nodes. Therefore the topology aggregation enables QoS routing to be run in large networks while it causes some errors during the aggregation process. In this paper, we introduce a way to optimize the topology aggregation to improve the performance of QoS routing in terms of exactness. Our scheme uses the partial optimization technique instead of whole topology optimization, which is general enough to be used with other existing schemes.