QoS provisioning via disseminated information on Differentiated Services class utilization

In a red/black dynamic network environment, differentiated services (DiffServ) classes are used to satisfy quality of service (QoS) requirements for the flows from the edge networks that are traversing the black core domain. In order to progress from using only local information to using domain-wide information in making QoS decisions such as admission control and preemption, hosts in an edge network need more information than they have locally. We describe a technique to determine the capacity and load of differentiated services classes along a path within a black core domain. The technique uses the same mechanism that RSVP uses to send a PATH message hop-by-hop along a route from a source to a destination. The information within the message is updated with local information at each node along the route until it reaches its destination. The results are returned to the source and sent through a one-way guard to the ingress router of the edge network, where they are placed in a hierarchy of information that is used for admission control. The hierarchy also includes local information and bandwidth and capacity estimates that we have described in our prior published work. We also describe an extension of the technique to the inter-domain case. Finally we describe the implementation of the technique in our QoS testbed and discuss plans for future work.