Master Thesis - 2001

In the future IP networks, various kinds of traffic will co-exist and rapidly increase their volume. Thus, it is the main technical problem to guarantee various QoS to each flow. However, it has been reported that typical congestion control scheme, RED (Random Early Detection), causes unfairness per flow especially for the TCP flows. Also, Diff-Serv (Differentiated Services) has been paid attention. Since it is the class-based control mechanism, unfairness per flow remains within the class. Moreover, to guarantee flexible QoS, routers must require flow-based control scheme.

The performance of DRED is evaluated by simulation, and performance improvement is shown. Also, it is confirmed that DRED is not influenced by set-up parameters greatly. This insensitiveness leads to high scalability.