Nokia 7705 SAR-W Series Manual page 99

MPLS Guide
Note: In order for the PCE to use the SRLG path diversity and admin-group constraints in
the path computation, the user must configure the SRLG and admin-group membership
against the MPLS interface and verify that the traffic-engineering option is enabled in the
IGP. This causes the IGP to flood the link SRLG and admin-group membership in its
participating area and for the PCE to learn it in its TE database.
10. The PE router sends a new PCRpt message to update the PCE with the Up state
11. If the user makes any configuration change to the PCE-computed or PCE-
Note: The above procedures are followed when the user performs a no shutdown on a
PCE-controlled or PCE-computed LSP. The starting point is an administratively down LSP
with no active paths.
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6. The PE router updates the CSM and the data path with the new path.
Up to this step, the PCC and PCE are using passive stateful PCE procedures.
The next steps synchronize the LSP database of the PCC and PCE for both
PCE-computed and PCE-controlled LSPs. They also initiate the active PCE
stateful procedures for the PCE-controlled LSP only.
7. The PE router sends a PCRpt message to update the PCE with the Up state and
the RRO as confirmation, including the LSP object with the unique PLSP-ID. For
a PCE-controlled LSP, the PE router also sets a delegation control flag to
delegate control to the PCE. The state of the LSP is now synchronized between
the router and the PCE.
8. Following a network event or reoptimization, the PCE computes a new path for
a PCE-controlled LSP and returns it in a path computation update (PCUpd)
message with the new ERO. It includes the LSP object with the same unique
PLSP-ID assigned by the PCC and the stateful request parameter (SRP) object
with a unique SRP-ID number to track error and state messages specific to this
new path.
9. The PE router updates the CSM and the data path with the new path.
and the RRO as confirmation. The state of the LSP is now synchronized
between the router and the PCE.
controlled LSP, MPLS requests the PCC to revoke delegation in a PCRpt
message (PCE-controlled only), and then MPLS and the PCC follow the above
steps to convey the changed constraint to the PCE, which will result in a new
path programmed into the data path, the LSP databases of the PCC and PCE
to be synchronized, and the delegation to be returned to the PCE.
For SR-TE LSPs, MBB is not supported. Therefore, the PCC first tears down the
LSP and sends a PCRpt message to the PCE with the remove flag set to 1
before following this configuration change procedure.
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MPLS and RSVP-TE
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