Time Properties of the BuST Protocol under the NPA Budget Allocation Scheme

Token passing is a channel access technique used in several communication networks. Among them, one of the most effective solution for supporting both real-time traffic (synchronous messages) and non real-time traffic (asynchronous messages), is the so-called timed-token protocol. Recently, a new token passing protocol, called budget sharing token protocol (BuST), was proposed to improve the existing timed-token approaches in terms of synchronous bandwidth guarantee, while guaranteeing a minimum throughput for the asynchronous traffic. This paper analyzes the ability of BuST to manage realtime and non real-time traffic in comparison with the classic timed-token protocol and its modified version, under the normalized proportional allocation (NPA) scheme. We will show that BuST achieves higher guaranteed realtime bandwidth than the original timed-token protocol, and improves the service for the non real-time traffic respect to its modified version.