LDP over MPLS TE

As shown in Figure 15, in a layered network, MPLS TE is deployed in the core layer, and the distribution layer uses LDP as the label distribution protocol. To set up an LDP LSP across the core layer, you can establish the LDP LSP over the existing MPLS TE tunnel to simplify configuration. You only need to enable LDP on the tunnel interfaces of the ingress and egress nodes for the MPLS TE tunnel. An LDP session will be established between the tunnel ingress and egress. Label Mapping messages are advertised through the session and an LDP LSP is established. The LDP LSP is carried on the MPLS TE LSP, creating a hierarchical LSP. For more information about MPLS TE tunnels, see "Configuring MPLS TE."