For static LSPs, the path and the label mappings and actions configured at each hop must be specified manually. RSVP-TE or LDP is not required for static LSPs.
For dynamic LSPs, RSVP-TE or LDP must be turned on. See RSVP and RSVP-TE or Label Distribution Protocol.
To implement dynamic pseudowire/VLL labels, entities must be enabled as follows:
MPLS must be enabled on all routers that are part of a static LSP
LDP must be enabled on the ingress and egress LERs
When MPLS is enabled and either RSVP-TE or LDP is also enabled, MPLS uses RSVP-TE or LDP to set up the configured LSPs. For example, when you configure an LSP with both MPLS and RSVP-TE running, RSVP-TE initiates a session to create the LSP. RSVP-TE uses the local router as the RSVP-TE session sender and the LSP destination as the RSVP-TE session receiver. Once the RSVP-TE session is created, the LSP is set up on the path created by the session. If the session is not successfully created, RSVP-TE notifies MPLS; MPLS can then either initiate backup paths or retry the initial path.