VPLS Research And Implementation

VPN has been used to provide cross-district network connection for entrepreneurial customers. Based on L2 VPN, VPLS(Virtual Private LAN Service) is a new resolution for setting up network connections among all the LANs of a company. Conbined with IP/MPLS protocol,VPN technology and Ethernet switching technology effectively, it provide multipoint to multipoint LAN connections for all the LANs distributed all over the world. These LANs belong to the same company. Judging by the connection manner of VPLS, it is a emulated LAN connection for entrepreneurial customers, making full use of the IP/MPLS core networks. But judging by network topology and the maintenance of service providers, VPLS service providers provide the same services just as VPN service providers does. The only difference between VPLS and VPN is: the service provider edge devices of VPLS use layer 2 bridging technolony and the counterparts make use of layer 3 routing technology.This paper introduces VPN technology, IP/MPLS protocol and VLAN technology at first, all of which is related to VPLS closely. Aftering formulating the operation and principle of VPLS, I give a basic resolution of VPLS. In order to improve its scalability, a hierarchical VPLS model is introduced. Aimed at the character of the hierarchical VPLS model, we solve the problem of the establishment and maintenance of PW in the hierarchical VPLS model. At the same time i analyze Dual Homing, Failure Recovery and scalability of VPLS. As Qos performance is important for VPLS customers, i research on the P2P Qos nd P2MP Qos of VPLS and educe the requirement of VPLS Qos. Then, some popular resolutions solving P2P Qos of VPLS are introduced. Finally, i propose a new on line distributed routing algorithm for supporting QoS bandwidth flow guarantees. The algorithm provides TE functionality over the P2MP VPLS connections in the core MPLS networks.