Intradomain QoS routing in IP networks: A feasibility and cost/benefit analysis

Constraint-based routing gradually becomes an essential enabling mechanism for a variety of emerging network services such as virtual private networki ng and QoS support. A number of recent works have recognized its significan ce and investigated many aspects of the operation of constraint-based routi ng and in particular its variant concerned with determining paths for reque sts with specific QoS requirements, known as QoS routing. In this work we b uild on previous results on the cost of QoS routing and investigate the per formance/cost trade-offs involved in the operation of a representative QoS routing architecture, elaborate on the constituents of this cost, and ident ify the main methods for containing the cost that QoS routing incurs on rou ters. Our results show that the cost of QoS routing is nor excessive and th at there indeed exist operational configurations, which can achieve reasona ble performance gains with only a minimal increase in processing cost when compared to conventional best-effort routing.