Global optimization is possible on the PCE also. Local optimization of a replication segment using PCEP is not supported. If the PCE calculates an optimized path for a candidate path, that instance is different from the current instance. The PCE has to download a new path instance with an LSP ID of 0 and the PLSP ID of the current candidate path. This behavior applies to replication segments only.
For any modification of the current path instance from the PCE to the PCC, the PCC-assigned LSP ID and PLSP ID are sent from the PCE to the PCC. This behavior ensures that the LSP ID of the replication segment for the existing path instances does not change.