METROPOLITAN ACCESS VIA TUNNEL TRANSPORTS

摘要

A method is provided of accessing a service network via a Layer 2 transport. The Layer 2 transport includes a customer facing and a core-facing device coupled to the service network. The method includes the steps of providing multi-protocol label switching (MPLS) label switched path between the customer-facing device and the core-facing device and establishing a Layer 2 tunneling protocol (L2TP) tunnel over the label switched path to transport traffic between the entity and the service network. The core-facing device includes module for an L2TP Network Server (LNS) functions that provides label swapping between the L2TP tunnel and an MPLS tunnel to the service network. The customer-facing device includes module for an L2TP Access Concentrator (LAC) function. The MPLS may be carried over an Ethernet network, such that the LAC and LNS are MPLS adjacent routes and use penultimate hop label stack popping to reduce the number of labels in the stack to a single label. The L2TP payload is also Ethernet and Layer 2 VPN services realized by the PE are one of LAN extension, Transparent LAN service, VLAN switched services and like Virtual Private Ethernet services.