Pce-Controlled Lsps - Nokia 7705 SAR-W Series Manual

MPLS Guide
4.5.3.3
The LSP MBB procedures for a PCE-controlled LSP (pce-control enabled) are as
follows.
Note: Items
resignal, and auto-bandwidth MBB types. The delayed retry MBB type used with the SRLG
on secondary standby LSP feature is not supported with a PCE-controlled LSP. See
Behavior of Secondary LSP Paths
LSP feature.
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2. If the PCE returns a path, the PCC signals the LSP with the RSVP control plane
and moves traffic to the new MBB path. If pce-report is enabled for this LSP,
the PCC sends a PCRpt message with the delegation D-bit clear to retain control
and containing the RRO and LSP objects, with the LSP-IDENTIFIERS TLV
containing the LSP-ID of the new MBB path. The message includes the metric,
LSPA, and bandwidth objects where the P-flag is clear, which indicates the
operational values of these parameters. Unless the user disables the report-
path-constraints option under the pcc context, the PCC also includes a second
set of metric, LSPA, and bandwidth objects with the P-flag set to convey to the
PCE the constraints of the path.
3. If the PCE returns no path or the RSVP-TE signaling of the returned path fails,
MPLS puts the LSP into retry mode and sends a request to PCE every retry-
timer seconds and up to the value of retry-count.
4. When the pce-report is enabled for the LSP and the FRR global revertive MBB
is triggered following a bypass LSP activation by a PLR in the network, the PCC
issues an updated PCRpt message with the new RRO reflecting the PLR and
RRO hops. The PCE releases the bandwidth on the links that are no longer used
by the LSP path.
5. If the user changes the RSVP-TE LSP configuration from pce-computation to
no pce-computation, MBB procedures are not supported. In this case, the LSP
path is torn down and is put into retry mode to compute a new path from the local
CSPF on the router to signal the LSP.

PCE-Controlled LSPs

1 through 5 of the following procedure apply to the config change, manual
1. The PCC temporarily removes delegation by sending a PCRpt message for the
corresponding path LSP-ID (PLSP-ID) with the delegation D-bit clear.
2. For an LSP with pce-computation disabled, MPLS submits a path request to
the local CSPF, which includes the updated path constraints.
3. For an LSP with pce-computation enabled, the PCC issues a PCReq for the
same PLSP-ID and includes the updated constraints in the metric, LSPA, or
bandwidth objects.
Use subject to Terms available at: www.nokia.com
for information about the SRLG on secondary standby
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