Of the proposed techniques, some allow the development of topological designs for interconnecting ATM switches in order to provide QoS guarantees for projected traffic loads. We are working on extensions that allow us to accommodate multipoint connections. In particular, we consider QoS-based routing techniques for multipoint connections under assumptions of large scale networks and multipoint groups, and of interactive applications with rather stringent QoS demands. The development of design techniques for routers and switches at an architectural level is also in progress. This work is based on characterizing the performance of current routing and forwarding algorithms on a range of simulated platforms in order to characterize where they are applicable.
Packet scheduling is a basic component of many routers and switches.
We are examining scheduling for multimedia latency-critical traffic, and are currently developing an experimental testbed to evaluate schedulers which can cope with traffic bursts imposed on a stream as it transits a network. The analysis of the upper bound on delay for one such scheduler is currently being worked out. The algorithm is currently being extended to account for the service of multiple recipients connected over heterogeneous links. Efficient traffic descriptors and call admission controls for VBR traffic which are independent of the encoding technique are currently being developed. We simulate mobility effects in order to model new protocols for the proper and efficient integration of services for mobile users with those supplied by fixed, reliable networks.