An end-connected dual bus topology for metropolitan area networks

We propose a new topology and the associated medium access protocol for Met ropolitan Area Networks (MAN's). The network uses a dual bus with connected ends as the topology. The protocol uses a token passing scheme with destin ation stripping as the access mechanism. Additional transmissions, referred here as restricted transmissions are also included in the protocol. These transmissions are made possible by the end-connected topology. Using this s cheme, a station can make use of even a reserved slot for transmission up t o the reserving station on the bus. This mechanism considerably improves th e network utilization over those of the conventional Distributed Queue Dual Bus (DQDB) and the Destination Stripping Dual Ring (DSDR) protocols. We ca rried out simulations to study the utilization and the delay characteristic s of the proposed protocol under various network conditions. We demonstrate that the performance of the proposed protocol is much better than that of the DQDB with slot reuse. (C) 1999 Elsevier Science B.V. All rights reserve d.