Selected Papers by Farooq Anjum

Future telecommunications networks will consist of integrated packet-switched (IP and/or ATM), circuit-switched (PSTN) and wireless networks. Service providers will offer a wide portfolio of innovative applications over these integrated networks. Doing so rapidly and efficiently requires open network APIs, with a key API being that for call control as well as coordination and transactions. The JAIN community is defining an API for Java Call Control (JCC) and Java Coordination and Transactions (JCAT). The JCC API defines the interface for applications to initiate and manipulate calls, while JCAT defines the facilities for applications to be invoked and return results before or during calls. Note that in this context a call refers to a multimedia, multiparty, multi-protocol communications session. The JCC/JCAT Edit Group of JAIN is in the process of defining the first version of the JCC/JCAT API specification, which is expected to be released in early 2000.

This introductory paper describes the background and motivation for the design of the JCC/JCAT API. We briefly describe the AIN and JTAPI call models, upon which the JCC/JCAT API is based. We then describe the scope of JCC/JCAT and its relationship to other JAIN Edit Groups defining facilities for enabling service creation. Finally we describe the requirements and example service drivers for JCC/JCAT, as well as the initial proposed design and structure for JCC and JCAT.

We present the architecture, design and experimental research prototype implementation of ChaiTime, an open system architecture for the rapid development of advanced next-generation telephony services that overcomes some of the limitations of the current closed PSTN architecture and service model. ChaiTime allows communication sessions to be set up over the PSTN, the Internet, or a combination of both. Services can be provided by multiple cooperating distributed service providers, some of whom may use third-party software components which can be "plugged in" or even dynamically downloaded from the network as needed. This allows advanced services to be deployed and delivered to users rapidly, a crucial requirement in the increasingly competitive telecommunications services marketplace.

ChaiTime is built upon an object-oriented call model called Java Call Control (JCC) which we have defined as a small set of extensions to the standard Java Telephony API (JTAPI) call model that allows support for distributed providers as well as advanced services. JCC hides details of underlying call-state management, protocols and hardware from applications. In our prototype, we have designed a small set of extensions to SIP, called Extended SIP, for supporting advanced services. The ChaiTime prototype software is currently operational in our laboratory. We briefly describe its current implementation as well as future work to address issues such as fault tolerance.

In next-generation enterprises it will become increasingly important to retrieve information efficiently and rapidly from widely dispersed sites in a virtual enterprise, and the number of users who wish to do using wireless and portable devices will increase significantly. This paper considers the use of mobile agent technology rather than traditional client-server computing for information retrieval by mobile and wireless users in a virtual enterprise. We argue that to be successful mobile agent platforms must coexist with, and be presented to the applications programmer side-by-side with, traditional client-server middleware like CORBAand DCOM, and we sketch a middleware architecture for doing so. We then develop an analytical model that examines the claimed performance benefits of mobile agents over client-server computing for a mobile information retrieval scenario. Our evaluation of the model shows that mobile agents are not always better than client-server calls in terms of average response times; they are only beneficial if the space overhead of the mobile agent code is not too large or if the wireless link connecting the mobile user to the fixed servers of the virtual enterprise is error-prone.