Point-to-Multipoint LSPs
A point-to-multipoint MPLS LSP is an RSVP LSP with multiple destinations. By taking advantage of the MPLS packet replication capability of the network, point-to-multipoint LSPs avoid unnecessary packet replication at the ingress router.
This process is illustrated in Figure 15. Router PE1 is configured with a point-to-multipoint LSP to routers PE2, PE3, and PE4. When router PE1 sends a packet on the point-to-multipoint LSP to routers P1 and P2, router P1 replicates the packet and forwards it to routers PE2 and PE3. Router P2 sends the packet to router PE4.
The following are some of the properties of point-to-multipoint LSPs:
- A point-to-multipoint LSP allows you to use MPLS for point-to-multipoint data distribution. This functionality is similar to that provided by IP multicast.
- You can add and remove sub-LSPs from a main point-to-multipoint LSP without disrupting traffic. The unaffected parts of the point-to-multipoint LSP continue to function normally.
- A node can be configured to be both a transit and an egress router for different sub-LSPs of the same point-to-multipoint LSP.
- You can configure paths statically.
For information on how to configure point-to-multipoint LSPs, see Configure Point-to-Multipoint LSPs.