Advertising the Forwarding Adjacency with OSPF
Once a forwarding adjacency LSP and the corresponding traffic engineering link you have configured, you can configure OSPF to advertise the forwarding adjacency. Unlike regular traffic engineering links, OSPF hellos are not exchanged between the forwarding adjacency LSP endpoints and therefore no routing adjacency is created between the forwarding adjacency endpoints. If you issue a show ospf neighbor command on an ingress forwarding adjacency, the command displays the egress router of the forwarding adjacency LSP as a neighbor. However, no real OSPF adjacency is established (no OSPF hellos are exchanged) between the ingress and egress routers. For display purposes only, OSPF creates a pseudo-neighbor corresponding to the peer.
You can configure forwarding adjacencies over existing MPLS networks. A forwarding adjacency LSP is signaled as a regular MPLS LSP without generalized MPLS (GMPLS) extensions. When the forwarding adjacency LSP is advertised as a traffic engineering link in OSPF, the corresponding traffic engineering link in OSPF is also advertised as a regular MPLS traffic engineering link without GMPLS extensions.
