LDP (Label Distribution Protocol) and RSVP (Resource Reservation Protocol) are two key protocols that operate in the control plane of P routers across the MPLS (Multiprotocol Label Switching) cloud. LDP is used for the distribution of label mappings between routers, facilitating the establishment of label-switched paths (LSPs). RSVP, on the other hand, is used for reserving resources along a specified path, enabling the creation of LSPs with specific quality of service (QoS) characteristics. These protocols are essential for the proper functioning and management of the MPLS network control plane.