Aggregated priority queueing as an efficient queueing mechanism to overcome effects of self-similarity

Differentiated Services (DiffServ) architecture is based on aggregation of traffic and, unlike the Integrated Services (lntServ) the resources are not reserved on a per flow basis. One of the current research issues is the provision of Quality of Service (QoS) guarantees to real time traffic in the DiffServ environment. The idea here is to achieve these guarantees without per flow resource allocation while safeguarding the best effort traffic from extremely high delays. The self-similar nature of Internet traffic that results in burstiness and very high delays has been identified in the recent past. The problem at hand is, what packet-scheduling scheme can be used to minimise delay to reasonable limits and the levels of control to be applied on the aggregated traffic to achieve such limits. We propose a class based aggregated Priority Queue with Lower Real time Traffic Utilisation (PQ-LRTU) as a packet-scheduling scheme that is capable of providing statistical delay guarantees for DiffServ networks. Since only a real time traffic utilization threshold is maintained at the entrance to the network to control traffic, it provides a simple mechanism. Overall queue efficiency is achieved by using different levels of delay tolerable lower priority traffic.