Advantages of Using Autodiscovery for VPLS Multihoming

Virtual private LAN service (VPLS) provides a multipoint-to-multipoint Ethernet service that can span one or more metropolitan areas and provides connectivity between multiple sites as if these sites were attached to the same Ethernet LAN.

VPLS uses an IP and MPLS service provider infrastructure. From a service provider’s point of view, use of IP and MPLS routing protocols and procedures instead of the Spanning Tree Protocol (STP), and MPLS labels instead of VLAN IDs, significantly improves the scalability of the VPLS service.

It is frequently a requirement for a service provider to supply its customers with redundant connectivity to one or more sites. This capability is called multihoming.

VPLS multihoming enables you to connect a customer site to two or more PE routers to provide redundant connectivity. A redundant PE router can provide network service to the customer site as soon as a failure is detected. VPLS multihoming helps to maintain VPLS service and traffic forwarding to and from the multihomed site in the event of the following types of network failures:

• PE router to CE device link failure

• PE router failure

• MPLS-reachability failure between the local PE router and a remote PE router

The Junos® operating system (Junos OS) supports both forwarding equivalency class (FEC) 128 and FEC 129. FEC 128 requires manually configured pseudowires. FEC 129 uses VPLS autodiscovery to convey endpoint information. After PE routers are autodiscovered, pseudowires are created automatically.

VPLS multihoming with support for FEC 129 enables you to interoperate with other vendor’s auto-discovery for LDP-signaled VPLS. This interoperability allows you to select the vendor that offers the best value.