Ingress PE Redundancy Configuration Overview

In many network topologies, point-to-multipoint label-switched paths (LSPs) are used to distribute multicast traffic over a virtual private network (VPN). When traffic engineering is added to the provider edge (PE) routers, a popular deployment option has been to use traffic-engineered point-to-multipoint LSPs at the origin PE. In these network deployments, the PE is a single point of failure. Network operators have previously provided redundancy by broadcasting duplicate streams of multicast traffic from multiple PEs, a practice which at least doubles the bandwidth required for each stream.

Ingress PE redundancy eliminates the bandwidth duplication requirement by configuring one or more ingress PEs as a group. Within a group, one PE is designated as the primary PE and one or more others become backup PEs for the configured traffic stream. The solution depends on a full mesh of point-to-point (P2P) LSPs among the primary and backup PEs. Also, you must configure a full set of point-to-multipoint LSPs at the backup PEs, even though these point-to-multipoint LSPs at the backup PEs are not sending any traffic or using any bandwidth. The P2P LSPs are configured with bidirectional forwarding detection (BFD). When BFD detects a failure on the primary PE, a new designated forwarder is elected for the stream.

For more information about traffic engineering, LSPs, and BFD, see the Junos MPLS Applications Configuration Guide.