Analysis And Design Of Router-type Broad Band Metro Aero Network

With the network scale and customer scale extending of Broad Band Metro Aero network,the critical question of the network is the efficiency and reliability, so the optimization of the Metro Aero Network is urgent. The paper based on the MAN (Metro Aero Network). rebuilding of Hunan telecom company, designs a network structure suiting MAN development and puts forward the solution of increase in value the business in MAN.First, the paper analyzes the current situation of the MAN. In the integral view of the network, the structure of the network is not clear enough, which causes the interconnection of the equipments is more than necessary. On the other hand, the ability of the network to support new service is not able to meet the requirement. It is because the network management and service control is not concentrated. The third problem is the lack of standard specifications on equipments, causing the non-unified performance of different equipments.Second,the paper proposes the structure model of the MAN based on the characteristic of the telecom companies. The model displays the multi-in of broad band and differentia services of user, proposes QoS and VPN technologies and makes the target network structure of the router-type Metro Area network. The above network has achieved several aimes such as the network levels are clear; its structure is flat and realizes the service for MAN differentia.Then,the paper designs the optimization proposal for the MAN network structure and the service structure in order to realize the requirements for the MAN transporting network as more aureola than straight-link and more single modules than multi modules. which is able to solve the bottleneck of broad band network and some problems in router protection. The network will be evolved from switch-type to router-type in steps, realize direct router for service access point control equipment and replace the 3-tier switches. The centralized management of the MAN is based on the strategy as central management, central charging and flexible identity. MAN will use QoS based on Diff-Serv, using the compatible DSCP and IP Precedence. The service access control point equipment will support the categorization, identification and band control of the services. The MAN backbone will do IP package transformation according to the sequence of DSCP class identity. MPLS is applied for large city, providing 2/3 tiers VPN connected to CN2 VPN by PE-ASBR, where the VPN is based on MPLS. The middle and small cities will use some pure IP core method such as L2TPv3+MPLS orVR to support the VPN service, and offer the customer with personalized and various service by 'technology combination'.After optimization and testing, we attain three goals: the network is more executable, maintainable and manageable. Combinations are formed, including Broad Band and Base Band, IP network and basic data network, voice data and multi-media business.