Miroslav Zivkovic

Authentication across heterogeneous networks

In the beyond third-generation (3G) vision, the convergence of different access network technologies is realized and end-user devices are able to roam seamlessly among them. Seamless roaming requires authentication to a network, which may require interaction with an end user that results in the termination of ongoing service sessions and, therefore, inhibits seamless roaming. Furthermore, some access technologies may support a plethora of authentication protocols, making selection of the appropriate method(s) of authentication challenging for an end user. We propose a solution involving single sign-on authentication that allows the end user to roam between different administrative domains and access network technologies (e.g., wireline and wireless). Our solution integrates a number of authentication mechanisms and does not require any end-user interactions while roaming, thus enabling a seamless roaming experience. We describe a prototype implementation of this solution using General Packet Radio Service (GPRS)/Universal Mobile Telecommunications System (UMTS∗)/wireless local area network (WLAN) networks and present our conclusions using measurements on this prototype.

Supporting QoS in broadband wireless and wired access

Wireless local area network (WLAN), cable, and digital subscriber line (xDSL) are among the most popular broadband access technologies in use today. In all such technologies, the transport capacity provided at the level of the physical medium is non-deterministically shared by different traffic streams generated by a multitude of applications. These traffic streams may have different or even incompatible characteristics (e.g., one may contain bursty best-effort traffic generated by file transfer, another streaming quality of service [QoS] traffic generated by video-on-demand), and they may interfere with one another. To accommodate admitted QoS traffic in a fluctuating available bandwidth and to protect it from high-load statistical traffic patterns, traffic must be regulated. This paper describes a ∗∗∗bandwidth-distribution mechanism for broadband access technologies that uses real-time characteristics of both the active-medium-sensing and the feed-forward control mechanisms. To validate this mechanism, two prototypes are developed, one based on wireless, the other on wired shared media. These prototypes employ legacy network elements without intrinsic QoS capabilities. Finally, we present the results of tests run on these prototypes and draw conclusions from our work.