Metropolitan area networks: Standards, services and performance

Abstract The paper, after a general survey of Metropolitan Area Network (MAN) issues, in which the market demand and recent trends in MAN concepts (e.g. relationship with Broadband Integrated Services Digital Network, B‐ISDN) are considered, examines the ongoing MAN related activities inside standard‐setting bodies such as IEEE (Institute of Electrical and Electronic Engineers) and ETSI (European Telecommunications Standards Institute). Emerging trends in architecture, protocols and services are reviewed. A more detailed characterization of the bearer services MANs are required to provide (i.e. connectionless, non isochronous connection oriented and isochronous) is then given, emphasizing their broadband nature and the related applications; the functions providing these services within the Distributed Queue Dual Bus (DQDB) framework are briefly described. The last section is devoted to a discussion of MAN performance. specifically in terms of fairness, focusing again on the DQDB protocol, which appears to be the most promising solution for MANs, and on possible improvements of its characteristics.