R3303-HP HSR6800 Routers MPLS Configuration Guide

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Figure 19 FRR node protection
Deploying FRR
When configuring the bypass LSP, make sure the protected link or node is not on the bypass LSP.
As bypass LSPs are pre-established, FRR requires extra bandwidth. When network bandwidth is
insufficient, use FRR for crucial interfaces or links only.
DiffServ-aware TE
Diff-Serv is a model that provides differentiated QoS guarantees based on class of service.
MPLS TE is a traffic engineering solution that focuses on optimizing network resources allocation.
DiffServ-aware TE (DS-TE) combines them to optimize network resources allocation at a per-service class
level. For traffic trunks which are distinguished by class of service, this means varied bandwidth
constraints. Essentially, what DS-TE does is to map traffic trunks with LSPs, making each traffic trunk
traverse the constraints-compliant path.
The device supports these DS-TE modes:
• Prestandard mode—Implemented by using HP proprietary mechanisms
• IETF mode—Implemented according to RFC 4124, RFC 4125, and RFC 4127.
Basic concepts
• Class Type (CT)—A set of traffic trunks crossing a link that is governed by a specific set of bandwidth
constraints. DS-TE allocates link bandwidth, implements constraint-based routing, and performs
admission control for a traffic trunk according to the traffic trunk's CT. A given traffic trunk belongs
to the same CT on all links.
• Bandwidth Constraint (BC)—Restricts the bandwidth for one or more class types.
• Bandwidth constraint model—Algorithm for implementing bandwidth constraints on different CTs.
A BC model comprises two factors, the maximum number of Bandwidth Constraints (MaxBC) and
the mappings between BCs and CTs. DS-TE supports two BC models, Russian Dolls Model (RDM)
and Maximum Allocation Model (MAM).
• TE class—A pair consisting of a CT and a preemption priority for the CT. The setup priority or
holding priority of an LSP transporting a traffic trunk from that CT must be the preemption priority for
the CT.
Note the following about the DS-TE modes:
• The prestandard mode supports two CTs (CT 0 and CT 1), eight priorities, and up to 16 TE classes.
The IETF mode supports four CTs (CT 0 through CT 3), eight priorities, and up to eight TE classes.
• The prestandard mode supports only RDM. The IETF mode supports both RDM and MAM.