Recent advances in wireless networking technology and the increasing demand for ubiquitous, mobile connectivity demonstrate the importance of providing reliable systems for managing reconfiguration and disconnection of components. Design of such systems requires tools and techniques appropriate to the task. Many formal models of computation, including UNITY, are not adequate for expressing reconfiguration and disconnection and are therefore inappropriate vehicles for investigating the impact of mobility on the construction of modular and composable systems. Algebraic formalisms such as the pi-calculus have been proposed for modeling mobility.

No abstract

Mobile computing represents a major point of departure from the traditional distributedcomputing paradigm. The potentially very large number of independent computing units, a decoupled computing style, frequent disconnections, continuous position changes, and the location-dependent nature of the behavior and communication patterns present designers with unprecedented challenges in the areas of modularity and dependability. So far, the literature on mobile computing is dominated by concerns having to do with the development of protocols and services. This article complements this perspective by considering the nature of the underlying formal models that will enable us to specify and reason about such computations. The basic research goal is to characterize fundamental issues facing mobile computing. We want to achieve this in a manner analogous to the way concepts such as shared variables and message passing help us understand distributed computing. The pragmatic objective is to develop techniques that facilitate the verification and design of dependable mobile systems. Toward this goal we employ the methods of UNITY. To focus on what is essential, we center our study on ad hoc networks, whose singular nature is bound to reveal the ultimate impact of movement on the way one computes and communicates in a mobile environment. To understand interactions we start with the UNITY concepts of union and superposition and consider direct generalizations to transient interactions. The motivation behind the transient nature of the interactions comes from the fact that components can communicate with each other only when they are within a certain range. The notation we employ is a highly modular extension of the UNITY programming notation. Reasoning about mobile computations relies on extensions to the UNITY proof logic.

This document summarizes the requirements collected from those sources, separating requirements for authentication, authorization and accounting. Details on the requirements are available in the original documents. Aboba, et al.

The CDMA community, under the umbrella of the 3rd Generation Partnership Project 2, has embarked on a standardization effort for wireless data based on Mobile IP. Important issues addressed include the link layer interface to a Mobile IP foreign agent; how link-layer mobility interacts with IP-layer mobility; how virtual private network services will be supported; and how to provide authentication, authorization, and accounting in a cellular Mobile IP environment. Members of 3GPP2 are also active in the Internet Engineering Task Force's Mobile IP, ROAMOPS, and AAA working groups. Based on our experiences in this effort, this article gives an overview of the issues we have encountered in standardizing a Mobile-IP-based network architecture in a cellular telephony environment, including current points of contention, and gives a summary of the current state of the standards.