The latest in VPNs: Part II
Chris Metz · IEEE Internet Computing · 2004
We describe the lastest in VPN. Virtual private networks (VPNs) can be configured and operated across a network provider's shared network infrastructure. The layer-2 VPN (L2VPN) is generating much interest and activity in the industry; it's defined as a VPN that transports native L2 frames across a shared IP network. Network providers will be able to reduce infrastructure and operation costs by taking traffic from L2-specific networks and running it over L2VPNs. An L2VPN transports native L2 frames across a shared IP or multiprotocol label-switching (MPLS) packet-switch network (PSN). The L2 frames can be frame-relay (FR) protocol data units, ATM cells, or even Ethernet frames; they're carried across the PSN using one of several different tunnel-encapsulation schemes. An L2VPN essentially provides the same set of services that native L2 LAN and WAN infrastructures support. We also discuss L2VPNs architecture and components.