Kenneth J. Crisler

Wireless network extension using Mobile IP

The development of distributed computing systems, with the associated focus on the interconnecting network, and mobile computing platforms has generated much interest in mobile data network access. Wide-area wireless communication systems are particularly of interest. This paper attempts to describe some of the challenges and potential solutions to providing wireless network access for mobile computing users. We present a set of characteristics and requirements for practical wireless access, many of which are not addressed well, if at all, by current wireless data systems. The paper then describes a new Internet technology, Mobile IP, which provides a foundation for addressing many of the cited requirements. The paper concludes with a description of how this technology is being applied in the development of advanced new data services for the integrated dispatch enhanced network (iDEN).

Wireless network extension using mobile IP

Over the last two decades, we have seen a dramatic shift in computing systems, away from the monolithic mainframe and toward increasingly distributed, client-server systems. One of the key elements enabling the success of the distributed computing environment was the interconnecting network technology. High-speed, reliable network hardware and protocols evolved to support client-server applications. Network technology has now progressed to the point that applications are being written to specifically exploit the capabilities of the network. The explosion of World Wide Web applications is the latest example of the fact that the network is now the focus of the distributed computing environment. In a concurrent development, personal computing platforms placed increasingly powerful systems in ever smaller form factors. Users have embraced these advances: Mobile computers, in the form of laptops, palmtops, and personal digital assistants (PDAs), are a significant element of the current computing environment. However, to be fully productive, the mobile computer user requires access to the network. Further, access to a network is not sufficient. Mobile users need access to the same network-the same resources and services and communications capabilities-that they would if they were at their desktops. We refer to this concept of providing home network access to the mobile user as network extension. Addressing many requirements for practical wireless access, this Internet technology aids the development of advanced data services for wireless networks, including the integrated dispatch enhanced network.

A wireless packet data link protocol with performance enhancements

A packet data protocol is described which provides connectionless packet data services for wireless and mobile radio data systems. Features of the protocol such as selective automatic repeat-request (S-ARQ) and multi-packet streaming allow efficient operation with error-prone channels and radio units limited to half-duplex operation. A detailed analytical model of the protocol is described, and protocol performance results are obtained.