Implementing Link-state Update Policies for Quality of Service Routing

Abstract

This thesis describes the implementation of available bandwidth link-state update policies for Quality of Service routing. Periodic, threshold-based and class-based policies are described and implemented in a QoS router testbed, using Quagga and its OSPF-API for low-level communications. The implementation is thoroughly tested using unit tests and simulated traffic. A performance comparison of the link-state update policies is done, using two different scenarios. The results of this comparison show that determining the right parameters for the policy is more important than the kind of policy used. The performance of the policies is generally worse than in previous work, due to the absence of explicit flow admission control, which makes it impossible to account for traffic until after it has been sent. The results also indicate that the use of a moving average instead of a hold-down timer leads to less link-state updates, while not impacting performance.