A head-of-line approximation to delay-dependent scheduling in integrated packet-switched networks

The chief cause of packet loss is the variability of end-to-end delay due to queuing at intermediate nodes. The queuing discipline used within the network directly affects this delay variance. In an integrated environment, scheduling must provide adequate performance for all classes. Simulation was used to compare the performance of several queuing disciplines for trunk scheduling at a packet switch with only voice traffic. A delay-dependent priority scheme, the budgeted residual-life-dependent discipline (BURD), resulted in the lowest packet loss rate at the node. BURD and a head-of-line discipline were then used to construct scheduling policies for networks with integrated traffic. It was found possible to approximate the performance of the delay-dependent priority schemes using more easily implemented head-of-line schemes and still provide adequate service for data traffic.<>