Research And Implementation Of Terabit Routers Vpls

Based on MPLS, ISP can offer the user VPLS service which is to provide connectivity between geographical dispersed LANs of the customer, as if they were all connected to an Ethernet switch. For MPLS infrastructures are invisible from the customers, VPLS is also called Transparent LAN Service ( TLS) .ISP uses PEs which is at the edge of the MPLS network to provide VPLS . For the sake of simplifying the avoidance of looping packets in VPLS, PEs in a VPLS are full meshed by VC. However, it results in the great difficulty to configure VPLS, especially with numerous PEs. To simplify the configuration of VPLS, it's necessary to introduce Auto- Discovery mechanism in VPLS for PEs to automatically establish VC with all the other PEs. At present, there are two primary signaling protocols for VPLS, BGP and LDP. In BGP, we can use BGP Route Reflector to implement Auto-Discovery mechanism in VPLS. However, because of its complexity, we are apt to adopt LDP, which is relatively simple, as the signaling protocol of VPLS in Terabit Router. Unfortunately, at present, there isn't Auto-Discovering function defined in LDP.This paper is devoted to research on the Auto-Discovering function in LDP and after that, an effective Auto-Discovery mechanism will be proposed for LDP. Then according to the system structure of 863 Terabit router and other factors, we will present a scheme of implementing VPLS in Terabit router. The main work of this dissertation is as follows: Based on the analysis of LDP and the process of VC creation in LDP, the shortcoming about VC-creating process in current LDP will be pointed out and then we will bring forward an improved process which allows one to only configure a PE to establish VC with the other PE. This improved process is the basis of the Auto-Discovering mechanism proposed in this paper. With the improved VC creating process above, if a PE is aware of all the other PEs' Transport Address in a VPLS, it will automatically establish VC with each of these PEs. According to this, a newly way for a PE to discover other PE's Transport Address is newly brought in LDP and then a method is proposed in this paper for PE to automatically discover all other PEs' Transport Addresses and its feasibility is theoretically proved. This Auto-Discovery mechanism reduces the configuration complexity of VPLS fromO(n~2) to 0{ri). Finally, based on the forementioned analysis and according to the system structure of 863 Terabit router and other factors, a scheme of implementing VPLS in terabit router system is presented. It can remarkably simplify the configuration of VPLS. Also, it assures the independence of the different VPLS instances in a PE.