Research On Implementation Scheme Of Flattening Metropolitan Area Network For BRAS Sinking

With the rapid development of network communication technology,people have placed higher demands on the stability of the network and the quality of information.In particular,the information in the fields of voice and video is increasing in a massive way.For the core equipment carrying the user service,the user access should be guaranteed.At the same time,it is necessary to ensure the stability of the user Internet access and the perception of the information acquisition procedure.China Mobile(CMNET)metropolitan area network is a network composed of routers,broadband access servers,switches and other types of data network equipment at the city level,which is between the provincial backbone network and the local city access network.In the existing metropolitan area network structure,the service control layer devices are placed on two core nodes in a centralized manner,and the aggregation layer switches are all connected to the core nodes.Such networking has the following disadvantages:(1)The transmission link is long,and the points of failure are concentrated;(2)The number of users accessing a single device is high,and the pressure on devices and links is large;(3)The capacity expansion is weak,which is not suitable for long-term business development.Therefore,in the planning of the CMNET metropolitan area network,the network structure of the existing network must be modified according to the requirements of the integrated access area and the carrying capacity of the future network,and the centralized service access must be gradually transferred into the district and county.The sinking of the service control layer router BRAS(Broadband Remote Access Server),which is represented by the core area,can flatten the entire CMNET metropolitan area network.BRAS sinking can effectively achieve the nearest user access,reduce the point of failure,reduce the number of route hops,improve user perception,and reduce the access layer cost,which is conducive to large-bandwidth service access.In this thesis,the flattening implementation scheme of the metropolitan area network is investigated for the BRAS sinking.Firstly,the hardware of the BRAS device,the characteristics of the routing protocol,the protocol principle of various services and the implementation of the service are elaborated.Then,by using the home and enterprise customers as important analysis models and the number of users and traffic flow as the supported data,via Tableau,the visualization application tool,the business distribution,traffic model,and user number statistics of the existing network of the metropolitan area network are analyzed and predicted.On this basis,the flattening scheme of metropolitan area network for BRAS sinking is studied in depth,the goal of flattening and networking model are proposed,and the disadvantages and advantages before and after flattening are compared.Furthermore,the flattening adjustment scheme of the metropolitan area network for the BRAS sinking is given.With the help of various protocols and analysis of the traffic user model,a flattening adjustment scheme for the home customers,enterprise customers and wireless local area network service is proposed in detail,and the scheme is verified and optimized through practice.The practical results show that in the forwarding performance,the network nodes become small after flattening,and the network delay has been reduced.In the number of faults,the network element level in the network is reduced,and the fault point has been decreased.In the degree of traffic congestion,the link congested possibility has been reduced.