Unicast vs. Multicast over Wireless: A Cross-Disciplinary Mindshare for Educational Application Researchers

Authors: Patrick Bristow - Microsoft Research

Complete Citation

• Bristow, P. 2006. Unicast vs. multicast over wireless: a cross-disciplinary mindshare for educational application researchers. ITICSE 2006, (Bologna, Italy, June 26 - 28, 2006). ITICSE '06. ACM Press, New York, NY, 242-244.

Abstract

As the state of learning technology advances, there is a pressing need to understand how we can best utilize and compensate for the bandwidth available to us over wireless networks. TCP traffic is ill-designed for an environment that subjects it to random packet loss, and because of which, it is plagued by congestion issues, unfairness, and insufficient bandwidth. While IP multicast traffic is not without its own burdens, such as lower overall throughput and “bursty” packet loss, we have found that it is often an appropriate and underutilized medium for data distribution in classroom-centric applications. We present the pros and cons of both unicast and multicast transmissions over wireless, follow with anecdotal evidence on what has worked in the past, and conclude with a discussion of the strategy we have taken and our future directions. This paper is intended to function as a means for distilling many years of work in understanding the properties of 802.11 wireless networks in the communications field, and transferring that knowledge to the field of computational technology for advancing CS education.

Annotations

This paper presents the issues associated with distributing multimedia to a classroom of students. This paper does not really solve any of the problems, just points out problems with the current approach. The author discusses two different means of transporting the data wirelessly to the students, TCP-unicast, and IP-multicast.

Related Work

• Fujisawa, H., Katsunori, A., Yamamoto, M., Yoshihiro, F. "Estimation of Multicast Packet Loss Characteristic due to Collision and Loss Recovery using REC on Distributed Infrastructure Wireless LANs." IEEE Wireless Communications and Networking Conference, 2004 (WCNC ’04) (21-25 March 2004), 399-404.

-- DavidSalyers - 13 Jun 2007