Multiprotocol label switching of virtual private networks, or MPLS VPN, is a set of techniques for using MPLS to create various VPN’s. MPLS VPN routes different types of traffic with efficiency and versatility using an MPLS structure.
The three types of MPLS VPNs that are used are:
- Point-to-point, also known as Pseudowire
- Layer 2, aka VPLS
- Layer 3, aka VPRN
Point-to-point, or pseudowire, uses virtual leased lines, VLL, to deliver Layer 2 point-to-point connectivity between sites. VLLs are used to compress ATM, Ethernet, and TDM frames.
One example of the numerous uses of point-to-point VPNs is condensing TDM T1 circuits connected with Remote Terminal Units.
Layer 2 VPN
Virtual private LAN service, or VPLS for short, is a service with a “switch in the cloud.” Essentially, this means VPLS allows for expanding virtual local area networks, VLANs, between sites. Layer 2 VPNs typically channels video, voice, and AMI traffic to the substation and the data center.
Layer 3 VPN
Virtual private routed network, or VPRN, uses layer 3 virtual routing and forwarding, VRF, to partition routing tables for each user. The customer has a specified routing table, allowing peering between service the provider router and the exchange routes. Multiprotocol BGP, or MP-BGP, is a requirement in the cloud, which escalates intricacy of design and application. L3 VPNs are usually too complex to be used effectively by utility networks; conversely, an L3 VPN is utilized best to direct traffic between datacenters and corporate locations.