Simulation study of ATN-DQDB interworking including connection-oriented variable bit rate service

The performance of a DQDB MAN supporting both connection oriented (CO) and connectionless (CL) services as observed at the point of attachment to an ATM network is the subject of this paper. The overall quality of service (QoS) preserved in the ATM-DATM-DQDB interworking is reflected in the traffic statistics of the multiplexed stream exiting the ATM- DQDB interworking unit (IWU). For the purpose of accurately generating this stream a simulation model is developed. This incorporates several source node traffic models for CO and CL services, the DQDB and IWU protocols as well as the signalling and metasignalling procedures activated for the establishment of end-to-end connections among communicating users. Through numerical evaluation of several access priority rules and protocol architectures we identify all those factors that are essential for the design of both the CO DQDB functions and the ATM-DQDB interworking components.