The performance of the FDDI token ring and IEEE 802.6 DQDB protocols are compared using discrete event simulation models. A metropolitan area network (MAN) of 100 km and with 50 stations was modeled. A 100 Mbps channel is used for both networks with a traffic model with large (1 kbyte) low priority packets and smaller (100 byte) high priority packets. The delay and fairness characteristics of both networks are analyzed. The simulations show that FDDI has advantages in fairness and maximum capacity, while DQDB offers lower delay at all except very heavy loads and has a stronger priority mechanism.>

The author concentrate on the provision of isochronous services to users via the existing IEEE 802.6 framework using Q.931 as the signalling protocol for providing call control functions. They present possible scenarios of isochronous service provisioning via the IEEE 802.6 network. Real time performance for call setup procedures is simulated and analyzed with different priority schemes for transferring signalling messages. The results show that using a prioritized queue arbitrated (QA) bandwidth to send signalling messages greatly reduces call setup delay. Call setup delays are determined using both Poisson-type and bursty type data traffic models. The positioning of the bandwidth manager, the virtual channel identifier (VCI) server and the Q.931 signalling termination is shown to influence call setup performance.>

Two candidate protocols for the generic flow control of the broadband integrated services digital network (B-ISDN) are currently being considered by the Accredited Standards Committee T1 (ASC T1). One proposal advocates the use of a distributed queue dual bus (DQDB)-like mechanism with a three level priority scheme. The other proposal is based on a slotted ring with control terminal equipment (C-TE), assigning periodic credit authorizations to the transmitting stations. This paper analyzes the performance behavior of the two protocols according to traffic scenarios and boundary conditions defined by the International Telephone and Telegraph Consultative Committee (CCITT) and T1.>