Supported Platforms
Related Documentation
Pseudowire Subscriber Logical Interfaces Overview
Subscriber management supports the creation of subscriber interfaces over point-to-point MPLS pseudowires. The pseudowire subscriber interface capability enables service providers to extend an MPLS domain from the access-aggregation network to the service edge, where subscriber management is performed. Service providers can take advantage of MPLS capabilities such as failover, rerouting, and uniform MPLS label provisioning, while using a single pseudowire to service a large number of DHCP and PPPoE subscribers in the service network.
The pseudowire is a tunnel that is either an MPLS-based Layer 2 VPN or Layer 2 circuit. The pseudowire tunnel transports Ethernet encapsulated traffic from an access node (for example, a DSLAM or other aggregation device) to the MX Series router that hosts the subscriber management services. The termination of the pseudowire tunnel on the MX Series router is similar to a physical Ethernet termination, and is the point at which subscriber management functions are performed. A service provider can configure multiple pseudowires on a per-DSLAM basis and then provision support for a large number of subscribers on a specific pseudowire. Figure 1 shows an MPLS network that provides subscriber management support.
At the access node end of the pseudowire, the subscriber traffic can be groomed into the pseudowire in a variety of ways, limited only by the number and types of interfaces that can be stacked on the pseudowire. You specify an anchor point, which identifies the logical tunnel interface that terminates the pseudowire tunnel at the access node.
Figure 1: MPLS Access Network with Subscriber Management Support
 | Note: Subscriber interfaces over MPLS pseudowires are supported on MX Series routers with MPCs. |
Figure 2 shows the protocol stack for a pseudowire subscriber logical interface. The pseudowire is a virtual device that is stacked above the logical tunnel anchor point on the physical interface (the IFD), and supports a circuit-oriented Layer 2 protocol (either Layer 2 VPN or Layer 2 circuit). The Layer 2 protocol provides the transport and service logical interfaces, and supports the protocol family (IPv4, IPv6, or PPPoE).
Figure 2: Pseudowire Subscriber Interface Protocol Stack
The pseudowire configuration is transparent to the subscriber management applications and has no impact on the packet payloads that are used for subscriber management. Subscriber applications such as DHCP and PPPoE can be stacked over Layer 2 similar to the way in which they are stacked over a physical interface.
