A number of wide-area mobile data networking technologies are in use or emerging. This paper addresses the issue of provisioning Internet access services seamlessly over different mobile networking technologies. To this end, an architecture based on the interworking of mobile-IP with existing and emerging mobile data services is presented. As a specific example, the interworking of mobile-IP with wireless ATM networking technology is examined.

There is an emerging interest in integrating mobile wireless communication with Broadband ISDN based on the ATM technology. Many issues arise when such integration is attempted. This paper addresses the problem of mobility management, i.e., that of tracking the current ATM addresses of mobile terminals and sustaining active ATM connections as mobiles move. The paper presents some architectural options for integrating wireless access to ATM networks and highlights an architecture based oninterworking devices to provide transparent mobility support in existing ATM networks. Location management and handoff solutions for this architecture are then presented. Also, how procedures for multiprotocol transport over ATM networks may be adopted to perform location management is described.

The efficiency with which multicast communication can take place is largely determined by the network level support available for such communication. Two factors contribute to the complexity of supporting current multicast applications: the lack of reliable multicast transport mechanisms at the network level and the lack of network support for large scale multicast communication. In this paper, we examine the issues pertinent to eliminating these shortcomings. We first show that internet multicasting algorithms based on reverse path forwarding are inherently unreliable and present a source-tree-based reliable multicasting scheme. The new scheme makes use of simple inter-gateway protocols and works on top of previously developed distance vector and link state internet routing schemes. Next, to support large scale applications, we present a scheme for partial multicasting and introduce a new network level operation, called gather. The partial multicasting mechanism allows messages to be delivered to subsets of multicast destinations, while the gather operation aids gateways in selectively suppressing redundant messages, thus reducing the message complexity. Using simulations, we investigate the efficacy of our schemes in supporting a sample application based on multicast communication.

A new transparent bridging scheme, called the source dependent spanning tree (SDS), is presented in which bridges observe broadcast packets from active hosts to create the shortest path trees for these hosts dynamically. Issues related to packet forwarding in the presence of multiple trees are identified and algorithms for addressing these issues are presented. Some important properties of SDS, such as correctness, are described, and it is compared with previously proposed schemes. Under standard traffic assumptions, it is shown that SDS can achieve load sharing and shortest-path routing without incurring excessive storage and communication overheads.>

Distributed shortest-path routing algorithms based on the Ford-Fulkerson method are simple to implement but they suffer from the cost-dependent looping problem: when link costs increase, routing table loops may form and convergence to correct paths may be too slow, depending on link costs. This problem can be eliminated if constraints are imposed on the order in which routing tables are updated at different nodes but the resulting internode protocols tend to be relatively complex. Furthermore, update constraints may restrict a node's ability to obtain alternate paths quickly in an environment where topology changes are frequent. In this paper, a new distributed shortest-path routing scheme based on the Ford-Fulkerson method is presented. Under the new scheme, each node uses partial topology information to eliminate the cost-dependent looping problem. No update constraints are imposed and no assumptions are made regarding link costs. In the worst case, the new scheme responds to link cost changes in O(D) update steps, where D is the diameter of the network after the occurrence of the changes.