Broadband integrated services digital network (BISDN) network architecture for local public serving areas is described. It is designed to offer end-users access to bandwidths up to 155 Mb/s. The BISDN protocols described support the simultaneous delivery of voice, data, image, and video services to business and residential customers. The objective of the broadband architecture described is to suggest designs that can evolve from today's base of narrowband equipment toward BISDN. It supports the use of fiber for narrowband services, in order to ensure that a broadband infrastructure is in place to serve as a platform from which broadband services can be offered. It also uses optional broadband modules on existing narrowband systems to facilitate evolutionary growth of broadband services and recognizes the metropolitan area network (MAN) protocol defined by IEEE 802.6 as a possible early implementation of BISDN.