Design And Application Of The Transit Topology Of Qingdao Metro Cable TV Backone Network

Reconstruction and optimization of the metro cable TV backbone network becomes increasingly urgent as the tri-play network and the cable network keep moving ahead. In particular, network topology of the transit system plays a big role in network performance, functions, reliability, etc., and is drawing more and more attention from network designers in the industry. This file introduces the transit system topology design of the cable TV backbone network in Qingdao and its application in the city's backbone network reconstruction project.In the design process, the industrial rules and regulations are followed and existing topology design examples are referred to so that network performance and feasibility are guaranteed while in line with the urban construction planning of Qingdao, thus realizing harmonious development for both the cable TV network and the Qingdao city.The highlight of this design is the creation of a hierarchical network system as the metro backbone network is divided into three layers: core (internetworking of core equipment rooms), backbone (internetworking of all transit equipment rooms in the same district) and edge (internetworking of certain equipment rooms in different districts). The regional feature of network construction facilitates various regional and individual applications and maximizes the utilization of network resources. By replacing the existing"single ring network"with the"partial mesh network", we can solve the problems of the single ring network such as poor scalability, low flexibility and high transit costs, further meeting the needs of ATM value-added services, EPON broadband services and IP data exchange services.The paper falls into five parts. Part 1 introduces the metro cable TV backbone and its problems, and stresses the importance of topology design of its transit system. Part 2 discusses the common types of topology and their characteristics and elaborates on the optical link calculation and network reliability calculation which are used in topology design of optical networks. Part 3 details the design process, including the layout of the transit equipment room, the hierarchy of the cable transit system and the choice of topology. Part 4 compares the new design with the existing topology, explaining the advantages of the new topology. Part 5 sums up the significance of the project and gives some suggests of possible future developments .