A PARALLEL MAC ARCHITECTURE FOR A GIGABITS S DQDB MAN SUITABLE FOR MULTIMEDIA APPLICATIONS/

Medium access control protocols based on a dual bus topology, such as the IEEE 802.6 Distributed Queue Dual Bus (DQDB), are usually consider ed to be highly satisfactory for high speed networks. But the DQDB can only partly support new sophisticated multimedia services, mainly bec ause the increase in the channel bit rate needed to meet the greater b andwidth requirements causes an increase in unfairness in the medium a ccess control of the nodes. In this paper the authors propose a Gigabi t/s Metropolitan Area Network (MAN) based on the IEEE 802.6 DQDB proto col and multichannel connectivity on optical fiber, by means of Wavele ngth Division Multiplexing (WDM). They present a parallel node archite cture in which N DQDB subnodes parallelly access N WDM channels. Chann el access at each node is regulated by N finite state machines operati ng independently and sharing a single MAC Convergence Functions (MCF) block for the segmentation and reassembly of user information. On the basis of the MAC architecture proposed, a network management structure is also presented, with particular reference to the Quality of Servic e monitoring processes. The proposed architecture is more modular than the DQDB standard; it provides greater fairness and better access del ay and allows efficient management of service classes with priority.