The evolution of optical transmission media and laser technology has made bandwidth an abundant commodity rather than a scarce one. This factor has been clearly recognized by the communications community. As a result metropolitan area networks have been described by some as an extension of local area networks, with the major distinction being that MANs cover a larger distance than LANs. There are several limitations to the approach of simply extending LAN technology to the MAN environment. In this paper a new perspective on MAN architecture is provided that differs from the evolving LAN architecture. Copyright © 1988 John Wiley & Sons, Ltd.