Optimal Guaranteed Services Timed Token (OGSTT) Media Access Control (MAC) Protocol for Networks That Support Hard Real-Time and Non Real-Time Traffic

Abstract

In networks that support real-time traffic and non-real-time traffic over the same physical infrastructure, the challenge to the Media Access Control (MAC) protocol of such network is the ability to support  the different traffic without compromising quality of service (QoS) for any of them. Generally, timed-token MAC protocols group the diverse real-time traffic into one category and then dedicate certain portion of the available bandwidth to them. At the same time, some bandwidth are left unassigned but available to the non real-time traffic. The unassigned bandwidth, and in some cases, the unused bandwidth left by the real-time traffic are assigned to the non-real-time traffic on best effort basis. In this paper, Optimal Guaranteed Services Timed Token (OGSTT) MAC protocol is developed and analyzed. In order to provide better support for both real-time traffic and non-real-time on the same local area network, OGSTT employs the timed-token mechanisms in the Timely-Token protocol along with that of Budget Sharing Token (BuST) protocol. Some bounds on the behavior of OGSTT protocol are discussed along with the ability of OGSTT protocol to support real-time and non-real time traffic. In particular, the paper demonstrated that the performance achieved by OGSTT is better than the Timely-Token and BuST. Furthermore, OGSTT protocol can be incorporated into the Ethernet network to provide real-time performance guarantees to multimedia applications and hard and soft real-time traffic.