Assignment of end-end transmission QoS in WAN environments

摘要

In an ATM-WAN linking ATM-LANs, it is very important to do traffic control across multilinks. Especially, when QoS of a call is required to be guaranteed, it is necessary to assign its requirement of QoS to each link from the source node to the destination node, and to calcualte QoS like transmission delay that each link can provide at the stage of call admission acceptance. After describing problems of existing QoS assignment schemes, this paper proposes a dynamic scheme that assigns end-end mean delay QoS to each link according to its traffic status. In our scheme, the concept of critical utilization factor of link is introduced to approximate the transmission delay the link can guarantee after a new call cccepted. For a simple network model with connections of three links, the call blocking rate and network utilization of the scheme were numerically analyzed and simualted. The numerical examples and simulation results show that the proposed scheme can hold down call blocking rate and promote the utilization of network resources.