Guaranteeing Fair Access For Multimedia Traffic Using the Smart Algorithm for Multicast ATM Connections

The cornerstone of the U.S. Navys implementation of network centric warfare is the Information Technology for the 21st Century IT-21 Intranet. The IT-21 Intranet relies on Asynchronous Transfer Mode ATM backbones for data transfer. An essential service provided by the IT-21 Intranet is video teleconferencing VTC. However, the current ATM standard does not support the multipoint-to-multipoint multicast requirements for robust VTC applications. This work builds upon the SMART algorithm, an existing protocol that provides support for ATM multipoint-to-multipoint multicast over a single virtual channel VCC, and modifies it to ensure that each source has fair access to the VCC. Fair access is ensured to multiple sources through the use of a metric that takes into account the relative magnitude of each sources queue size and cell age. The improved SMART algorithm is modeled using the MIL3s Optimized Network Engineering Tool OPNET. Fair access to each source is shown using both audio and video source models. VCC utilization is examined and shown to improve for the video case as the number of sources increase. The increased overhead due to the use of Resource Management RM cells is also examined.