Mpls-based Vpn Technology

The MPLS (Multiprotocol Label Switching) technology is the latest evolutions in the integrate router/switching solution. It combined the flexibleness of router and the concision of switching. The basic idea of the technology is using a short fixed label to remark the data packet and transmitting the label with the data packet. The following network node will get the information of the destination address and the other properties and then accomplish transmitting the data packet according the information.The private network became the extreme important network. For the VPN is a new service, which can establish virtual networks for enterprise and client by utilizing the common network, it saves net recourse and makes it easy to maintain the net. That is why the technology is becoming more and more popular.The data of VPN client is translated by many tunnels, so the main technology of VPN is tunnel. VPN can be supported by MPLS for MPLS itself is a tunnel technology.There are two main methods to realize VPN in MPLS. The first one is Cisco's BGP VPN; the other one is Nortel's VR VPN. They both are using two labels to establish IP VPN: the bottom label represents VPN and the top label represents LSP The main difference of the two methods is that VR VPN using LDP protocol and BGP VPN using expanded BGP protocol. VR VPN can enlarge service and is administered easier than BGP VPN.To reduce facility's cost, many factories use ASIC to replace common 1C. In this paper, I described the design method of ASIC, and then described how to realize VPN which is based on MPLS in a ASIC .