Implementation of Traffic Conditioning and PHB mechanisms in OPNET
Abstract: Differentiated Service Model (DiffServ) is currently a popular research topic as a low-cost method to bring QoS to today’s Internet, especially in the backbone. The DiffServ architecture consists of two key components: traffic conditioning at the edge and Per Hop Behavior (PHB) at the edge and the core. Traffic Conditioners contain various elements such as classifier, meter, marker, shaper and dropper. The PHB mechanisms include the queue management and the scheduling. This paper addresses the impact of traffic conditioning and PHB mechanisms implemented in routers (edge) on the overall performance in Differentiated Services architecture, by using OPNET as the simulation tool. We have implemented the single and dual Token Bucket algorithms, the WRED/RIO queuing schemes with two sets of parameters (min, max, maxp), the RED dropping schemes, and the packet schedulers First In First Out (FIFO) and Weighted Fair Queuing (WFQ). A number of different Network Services has implemented,each one using a different traffic class. Each traffic class uses a different traffic profile and output queue. We investigate the effect of network transient, as expressed by changes in traffic load, on the performance of the scheduling algorithms and queuing/dropping schemes, in terms of both packet delay and queue size requirements.The simulation results are relative with the utilization on the backbone interface.