AURORA is one of five US testbeds charged with exploring applications of, and technologies necessary for, networks operating at gigabit per second or higher bandwidths. The authors provide an overview of the goals and methodologies employed in AURORA and report preliminary results from the first year of research. AURORA is an experiment in collaboration, where government support has spurred interaction among centers of excellence in industry, academia, and government. The emphasis of the AURORA testbed is research into the supporting technologies for gigabit networking. The targets include new software architectures, network abstractions, hardware technologies, and applications. The AURORA testbed will provide a platform in which researchers can explore business and scientific applications of gigabit networks, while evolving the network architecture to meet the needs of these emerging applications.>

Three directory schemes are investigated: the local cache (LC) scheme in which there is a cache at the network nodes to store the results of a previous query for a remote resource so that a subsequent query for that resource can be resolved locally, and two enhancements of this scheme, namely the regional cache server (RCS) scheme and the cooperating cache servers (CCS) scheme, in which the queries not resolved locally are funneled through designated nodes or servers to reduce multiple network searchers for a given resource. The performance of these schemes in terms of the network search rate is dependent on the cache sizes at the nodes and servers, the probability distribution for queuing resources, and the cache replacement policy used to displace resources from the cache to accommodate newly discovered ones. Two policies are investigated: A/sub 0/, which is the optimal policy for the LC scheme, and the least recently used policy, which is of practical importance.>

A design is presented for rerouting existing sessions (virtual circuits) under certain conditions to improve the routing performance. The authors call this mechanism selective load redistribution (SLRD). SLRD is a fully distributed algorithm which redistributes sessions in parallel at different nodes by carefully selecting the amount of traffic to be switched. The performance of the algorithm is evaluated by a simulation model. The results for several sample networks show that the algorithm performs very well even though the information available to the nodes for route computation may not be completely accurate.>

The authors develop distributed routing algorithms for large computer networks that provide virtual circuit connections to end users. One routing scheme in computer networks is to use a topology database maintained at each node that contains information about nodes and link cost. Using this information, each node finds shortest routes to other nodes. This scheme may be inefficient in large networks since the overhead associated with topology database update and shortest path computation may become large. One way of solving this problem is to partition the network into subnetworks or clusters. After partitioning, each node in a cluster only maintains a topology database of nodes and links in its own cluster and possibly marginal information about the entire network. For intracluster communication, shortest path routes are provided. For intercluster communication the source node collaborates with other nodes to find a path to the destination node. The authors propose two collaboration schemes that use simple protocols among network nodes. In one scheme, a broadcast search is used to find a path to the destination node in other clusters. In the other scheme each node maintains information about intercluster links on an up/down basis as well as complete topology database of its own cluster. Using this information, it finds a path to the destination node with the help of border nodes (nodes sharing intercluster links) in the intermediate clusters.>