The DQDB Network in the Presence of CBR Sources

概要

論文の詳細を見る
The increasing demand for services that deal with a multitude of different traffic types has shaped the design of many high-speed networks. The DQDB network is one of these proposals for the metropolitan area; it is also compatible with ATM in terms of cell size. The current adopted mechanism for isochronous services in DQDB is the use of PA slots[1]. These slots are Pre-assigned by the head-of-bus. Only users who have previously requested an isochronous channel can access these slots. In other words, a fixed portion of the bandwidth is assigned to isochronous channels. Of course, the unused part of this bandwidth is wasted. Recently, a proposal that utilizes the QA (queue-arbitrated) slots for isochronous traffic has been proposed[2] and studied[3]. This is referred to as Guaranteed bandwidth Protocol (GBW). In the present work, we give simulation results of the DQDB performance in the presence of constant bit rate (CBR) traffic, which are expected to be one of the major types of traffic to be supported by ATM networks[4]. The adopted performance measure is the interdeparture time of the P-segments (P for periodic)[4]. Also, motivated by [4] we propose a modified GBW (MOD-GBW), which is a simple variation of the GBW protocol. Simulations show that MOD-GBW is better than GBW.
一般社団法人電子情報通信学会の論文
1994-09-26