NSP procedures

The NRC-P controls the creation and the deletion of the PCE-initiated LSPs.
All LSP creation retries are performed by the NSP. If the PCC rejects an instantiation, the NSP can issue a new request for instantiation or give up and delete the LSP state locally after a configured maximum number of retries.
The NSP can reject an instantiation request if it does not receive a PCRpt message from the PCC message within a configured time frame.
When the PCEP session comes up and the LSP database synchronization from the PCC to PCE is complete, the NSP reinitiates the PCE-initiated LSPs that are missing from the PCC reports.
If a PCEP session goes down, the NSP stops sending any new or updated PCE-initiated LSP paths to that PCC; therefore, the LSP database on the NSP and PCC can go out of synchronization during that time.
If the PCEP session to a PCC goes down, the NSP marks all PCE-initiated and PCC-initiated LSPs for that PCC as stale but keeps their reservation for an amount of time equal to the state timer. The state timer applies to both PCE-initiated and PCC-initiated LSPs on the PCE and is set to a fixed value of 10 minutes.
Note: The state timer on the PCE must be considerably larger than the maximum state timer amomg all the PCCs (configurable via config>router>pcep>pcc>state-timer) to give the PCC time to clean up PCE-initiated LSPs and prevent PCInit requests for duplicate LSPs.
- If the PCEP session was reestablished within that time, the NRC-P reinitiates all PCE-initiated LSPs toward the PCC from which a PCRpt remove message with the special error code LSP_ERR_SYNC_DELETE was received during the LSP database synchronization with the PCC.
- If the state timer expires, the NRC-P releases the resources but does not delete the LSPs from the LSP database. If the PCEP session comes up subsequently, the NSP recomputes the path of each LSP from which a PCRpt message with the remove flag set in the LSP object and with the special error code LSP_ERR_SYNC_DELETE received during the LSP database synchronization with the PCC, and sends the PCC a PCInitiate message for each LSP.
If the NSP is informed by the VSR-NRC of a PCRpt message with the remove flag in the LSP object and SRP object set for each of them, it follows the same procedures for these LSPs as when the PCEP session goes down.