Topology and survivability of future transport networks

The author discusses the issues surrounding physical and logical transport topology networks, as well as network survivability, and proposes an initial physical topology to support voice, data, and video services. Topology considerations for bursty and nonbursty information transfer are discussed for narrowband and broadband services. Factors influencing the choice of topology are cost, implementation difficulty, planning complexity, operational support, survivability, and routing capabilities. In addition, the author discusses implementation strategies where existing interoffice routes are mapped into high- and medium-density ring structures. During this same time, local loop fiber feeds would initially be mapped to campus and LAN/MAN (local/metropolitan area network) networks where a high density of workstations exist. A two-phase implementation strategy provides a transition from today´s interoffice metallic mesh networks by first establishing a fiber ring network on a link-by-link basis. Once the link-by-link fiber ring is established, a second phase will establish an integrated fiber ring by connecting the individual links together. A four-phase potential implementation strategy provides a transition from today´s local loop metallic tree networks to form a ring-on-ring, survivable distribution facility. This strategy establishes primary and secondary fiber routes and primary and secondary ring completions