Cellular digital packet data

In a Personal Communication Services (PCS) network, mobile hosts communicate with other mobile hosts through base stations over a wired network. The mobile hosts connect to different base stations through wireless links and the base stations to which mobile hosts are connected change depending on the current location of the mobile hosts. In this environment , the problem of efficiently delivering a multicast message from one mobile host to a group of other mobile hosts becomes challenging. This paper presents a multicast protocol that delivers multicast messages from a mobile host to a group of other mobile hosts without flooding the wired network. Three user location strategies are discussed in this paper, upon which the multicast protocol is built. The basic multicast protocol proposed guarantees exactly-once message delivery to all mobile hosts in the multicast group and also ensures that multicast messages are delivered in FIFO order from the point of view of the base station that originates the multicast message (referred to as BS-FIFO). Additionally, an extension of the basic protocol is provided that, unlike earlier work delivers multicast messages in FIFO order from the point of view of the mobile host that initiates the multicast message (referred to as MH-FIFO). The modifications to be made to the multicast protocol to accommodate each of the three models of user location is also described. Interoperability requires that communicating systems support compatible protocols, which remains as a major problem in heterogeneous networks, especially in a wireless infrastructure where hosts can move from one protocol environment to another. It is possible to improve the flexibility of a communication network's operation by deploying systems capable of supporting multiple protocols. These multiprotocol systems require support mechanisms that enable users to effectively access the different protocols. Of particular importance is the need to determine which of several protocols to use for a given communication task. This article proposes an architecture for a protocol discovery system that uses directory services and protocol feedback mechanisms to determine which protocols are supported. The issues related to protocol discovery and present protocol features necessary to support multiprotocol systems are also described. This paper addresses two critical issues in mobile networking , namely location management and handoff in the content of wireless ATM. It introduces a wireless ATM network architecture that integrates location management and handoff within ATM signaling and control framework. The architecture assumes an out-band signaling is employed …