Route Pinning; Tunnel Reoptimization - HP MSR2000 Configuration Manual

CRLSPs separately. The make-before-break mechanism uses the SE resource reservation style to address
this problem.
The resource reservation style refers to the style in which RSVP-TE reserves bandwidth resources during
CRLSP establishment. The resource reservation style used by an MPLS TE tunnel is determined by the
ingress node, and is advertised to other nodes through RSVP.
The device supports the following resource reservation styles:
• FF—Fixed-filter, where resources are reserved for individual senders and cannot be shared among
senders on the same session.
SE—Shared-explicit, where resources are reserved for senders on the same session and shared
•
among them. SE is mainly used for make-before-break.
Figure 22 Diagram for make-before-break
As shown in
D through the path Router A—Router B—Router C—Router D.
To increase the reserved bandwidth to 40 M, a new CRLSP must be set up through the path Router A—
—Router E—Router C—Router D. To achieve this purpose, RSVP-TE needs to reserve 30 M bandwidth for
the old CRLSP and 40 M bandwidth for the new CRLSP on the link Router C—Router D. However, there
is not enough bandwidth.
Using the make-before-break mechanism, the new CRLSP can share the bandwidth reserved for the old
CRLSP. After the new CRLSP is set up, traffic is switched to the new CRLSP without service interruption, and
then the old CRLSP is removed.

Route pinning

Route pinning enables CRLSPs to always use the original optimal path even if a new optimal route has
been learned.
On a network where route changes frequently occur, you can use route pinning to avoid reestablishing
CRLSPs upon route changes.

Tunnel reoptimization

Tunnel reoptimization allows you to manually or dynamically trigger the ingress node to recalculate a
path. If the ingress node recalculates a better path, it creates a new CRLSP, switches traffic from the old
CRLSP to the new, and then deletes the old CRLSP.
MPLS TE uses the tunnel reoptimization function to implement dynamic CRLSP optimization. For example,
when MPLS TE sets up a tunnel, if a link on the optimal path does not have enough reservable bandwidth,
Figure 22, a CRLSP with 30 M reserved bandwidth has been set up from Router A to Router
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