Delay-based quality of service through intra-domain differentiated routing with optimised link weight setting

The wide range of applications that are supported on the Internet requires it to deliver a diverse set of classes of service. For example, network providers need to support both delay-sensitive multimedia services and less time-sensitive applications such as web browsing and peer-to-peer transfers. Differentiated routing is one approach to delivering these different classes of service. In this paper we use an evolutionary algorithm to set link weights for our previously described Intra-Domain Differentiated Routing algorithm (IDDR) so as to optimise the delay differentiation between two classes of flows. In order to provide good robustness, the link weight setting is based on multiple traffic matrices. Results demonstrate that the delay for high QoS traffic is typically less than 60% of the delay for best effort traffic, and that this can be achieved across a wide range of traffic matrices. We also show that the delay differentiation is achieved by sending high QoS flows along paths that have fewer links and that those links have in general lower delay.