The NRC-P controls the creation and the deletion of the PCE-initiated
LSP.
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 configurable maximum number of
retries.
The NSP can reject an instantiation request if it does not receive a PCRpt from
the PCC message within a configured timeframe.
When the PCEP session comes up and the LSP DB 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 DB 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-timeout timer.
The state-timeout 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-timeout timer must be
considerably larger than the maximum state timer on the PCC to give the PCC
time to clean up PCE-initiated LSPs and prevent PCInit requests for
duplicate LSPs.
If the PCEP session was re-established within that time, the NRC-P
reinitiates all PCE-initiated LSPs toward the PCC from which a PCRpt
remove with the special error code LSP_ERR_SYNC_DELETE was received
during the LSP DB synchronization with the PCC.
If the state-timeout timer expires, the NRC-P
releases the resources but does not delete the LSPs from the LSP DB. If
the PCEP session comes up subsequently, the NSP recomputes the path of
each LSP from which a PCRpt remove with the special error code
LSP_ERR_SYNC_DELETE was received during the LSP DB 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 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.