Bay Area Research Wireless Access Network (BARWAN)

Technical Approach Overview

• Seamless Integration of Overlay Networks: No general network management architecture exists for effectively integrating multiple overlay networks. Mobile applications roaming across overlays requires network intelligence to determine that the mobile has moved from acceptable coverage in one network to better coverage in another. But a global network management algorithm is stilled needed to control handoffs across overlays based on current mobile connectivity. Link quality is only one metric that determines handover; priority of access, applications needs, and relative cost are equally important. Since overlays may not cooperate with one another to render such decisions, we will demonstrate mobile assisted handoff in which the mobile host must be an active participant in handoff processing.

• Support Services for Mobile Applications: Handover across overlays will change an application's network bandwidth and latency. We will design a new applications interface to the network management layers to allow them to initiate handovers, to determine changes in their current network capabilities, and to gracefully adapt their communications demands. We will better integrate mobile applications and scalable wireline processing and storage capabilities through an agent processing architecture that exploits data type specific transmissions to manage the communications demands over dynamically varying wireless links.

• Managing Mobile Connections to Support Latency-Sensitive Applications: Handoffs must be executed with lower latency than is now possible if (near) real-time multimedia applications are to be well supported. One strategy moves the routing and resource allocations to local subnets. For example, roaming authentications can be cached locally to avoid repeated remote, latency-intensive transactions. We will develop algorithms that exploit information about the location of mobile devices, the geographical adjacency of cells, and the likely routes devices might take, to improve handoff processing. End-to-end strategies like Mobile IP provide routing, but fall far short for latency-sensitive connection-oriented services. More hierarchical approaches, which localize information collection to the region or the subnet containing the users, are more scalable.

• Load Balancing for Scalable Mobile Processing: Repositioning within future wireless networks will be a common event. Traffic patterns will not be uniform, with high correlations between mobile host location, their repositionings, and their requests for service. We are developing network management architectures that build on decentralized algorithms to allocate network and processing resources on demand, avoiding the static and centralized schemes of the past. Furthermore, overlay networks provide an opportunity to share bandwidth and processing across networks; current network load is one reason to initiate internetwork handoff.