Vpls Signaling Software Implementation

The traditional layer 2 VPN shares one common characteristic: they provide only point-to-point connectivity. Virtual Private LAN service (VPLS), which is a new and enhanced layer 2 VPN, on the other hand, was built for multi-point connectivity and has broadcast capability like a common LAN. In contrast with the traditional Layer 2 VPN and Layer 3 VPN, VPLS has more advantages over them. VPLS can consolidate layer 2 VPN and layer 3 VPN into one network infrastructure. While in the past, layer 2 VPN can only provide point-to-point connectivity. To support layer 3 VPN, a separate network has to be built to meet for this demand. This will result in service providers having to maintain separate layer 2 VPN and layer 3 VPN network, which is very difficult and costly. Service providers and customers will benefit from this new technology. So it is necessary to develop VPLS software and to do so will make service providers increase profitability.At the same time, Ethernet has become the dominant technology for Local Area Network connectivity and is gaining acceptance as an access technology, specifically in Metropolitan and Wide Area Networks. And MPLS is a new forwarding technology and it has unparallel advantage over the traditional IP forwarding technology. VPLS provide connectivity between geographically Ethernet customers across service provider's MPLS backbone network, as if they are connected by a true common LAN.VPLS consists of two planes: control plane and forwarding plane. The control plane is the key component of VPLS. The control plane mainly facilities data plane, that is, control plane will tell data plane how to forward the data. In draft-Martini we use LDP (Label Distribution Protocol) as our signaling protocol in control plane. While in draft-Kompella, we use BGP (Border Gateway Protocol) as signaling protocol in VPLS. In our implementation we adopt draft-Martini scheme.Firstly, we compare VPLS with tradition Layer 2 VPN and Layer 3 VPN, introducing the advantages of VPLS. And some key technologies in VPLS are introduced. Then some of LDP's functions are demonstrated. Then we analyze the VPLS scheme based on draft-Martini and especially demonstrate some extended...