Which protocol is used for communication between the PCE and PCC?

ICMP is primarily used for diagnostic purposes and error reporting, not for the complex path computation requests and responses characteristic of PCE-PCC interaction.

The Path Computation Element Protocol (PCEP) is specifically designed for communication between a PCE and a PCC. It enables PCCs to request path computations from a PCE and allows PCEs to provide optimal paths, synchronize state, and update path information.

CEF is a high-speed packet forwarding mechanism used on Cisco routers, not a protocol for inter-component communication in MPLS-TE path computation.

POP (Post Office Protocol) is an application-layer protocol for retrieving email and is entirely unrelated to network path computation elements.