PCEP
322
MPLS Guide
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Step 6. The PE router updates the CPM and the data path with the new path.
Up to this point, the PCC and PCE are using passive stateful PCE
procedures. The next steps will synchronize the LSP database of the PCC
and PCE for both PCE-computed and PCE-controlled LSPs. They will also
initiate the active PCE stateful procedures for the PCE-controlled LSP only.
Step 7. The PE router sends a PCRpt message to update the PCE with an Up
state, and also sends the RRO as confirmation. It now includes the LSP
object with the unique PLSP-ID. For a PCE-controlled LSP, the PE router
also sets the delegation control flag to delegate control to the PCE. The
state of the LSP is now synchronized between the router and the PCE.
Step 8. Following a network event or a reoptimization, the PCE computes a new
path for a PCE-controlled LSP and returns it in a PCUpd message with the
new ERO. It will include the LSP object with the same unique PLSP-ID
assigned by the PCC, as well as the Stateful Request Parameter (SRP)
object with a unique SRP-ID-number to track error and state messages
specific to this new path.
Step 9. The PE router updates the CPM and the data path with the new path.
Step 10. The PE router sends a PCRpt message to inform the PCE that the older
path is deleted. It includes the unique PLSP-ID value in the LSP object and
the R (Remove) bit set.
Step 11. The PE router sends a new PCRpt message to update PCE with an Up
state, and also sends the RRO to confirm the new path. The state of the
LSP is now synchronized between the router and the PCE.
Step 12. If PCE owns the delegation of the LSP and is making a path update, MPLS
will initiate the LSP and update the operational value of the changed
parameters while the configured administrative values will not change.
Both the administrative and operational values are shown in the details of
the LSP path in MPLS.
Step 13. If the user makes any configuration change to the PCE-computed or
PCE-controlled LSP, MPLS requests that the PCC first revoke delegation
in a PCRpt message (PCE-controlled only), and then MPLS and PCC
follow the above steps to convey the changed constraint to PCE which will
result in the programming of a new path into the data path, the
synchronization of the PCC and PCE LSP databases, and the return of
delegation to PCE.
The above procedure is followed when the user performs a no shutdown command
on a PCE-controlled or PCE-computed LSP. The starting point is an LSP which is
administratively down with no active path. For an LSP with an active path, the
following items may apply:
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