ts) ISO 8823, IPS - OSI - Connection Oriented Presentation Protocol ISO 9545, IT - OSI - Application Layer Structure Specification ISO 9579, IT - Database Languages - Remote Database Access - ISO 8824, IT - OSI - Specification of Abstract Syntax Notation (2 parts) One (ASN.1) ISO 8825, IT - OSI - Specification of Basic Encoding Rules for ISO 9804, IT - OSI - Service Definition for the Commitment, Abstract Syntax Notation One (ASN.1) Concurrency and Recovery Service Element ISO 8886, IPS - Data Communication - Data Link Service Defini- ISO 9805, IT - OSI - Protocol Specification for the Commitment, tion for OSI Concurrency and Recovery Service Element ISO 9040, IT - OSI - Virtual Terminal Basic Class Service ISO 10022, IT - OSI - Physical Service Definition ISO 9041, IT - OSI - Virtual Terminal Basic Class Protocol - (2 ISO 10026, IT - OSI - Distributed Transaction Processing - (5 parts) parts) This page intentionally left blank Multiple access techniques Fraidoon Mazda MPhil DFH DMS MBIM CEng FIEE Northern Telecom Contents Introduction 13/3 Queuing theory 13/3 13.3 Performance parameters 13/4 13.4 Classification of multiple access techniques 13/5 Pure contention systems 13/5 13.6 Contention minimisation systems 13/8 13.7 Non-contention systems 13/13 13.8 References 13/21 This page intentionally left blank Introduction 13/3 13.1 Introduction used forms. The star network is usually seen in configurations such as lines terminating within a central controller or switch. It is well Communication bandwidth is a scarce commodity, whether it be suited to carry out a polling mechanism from the central location to carried on copper wire, fibre optic cable or by the air waves. The outlying nodes, for multiple access. need to share this bandwidth fairly and efficiently between multiple Ring topologies are often preferred since they are not dependent users is therefore crucial. Many techniques have been developed to on a single control site, and can generate traffic in either direction enable multi-users to share, and especia