Mpls Traffic Engineering Interarea Tunneling; Interarea Support; Multiarea Support - Cisco CRS Configuration Manual

Implementing MPLS Traffic Engineering

MPLS Traffic Engineering Interarea Tunneling

These topics describe the following new extensions of MPLS-TE:
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Interarea Support

The MPLS-TE interarea tunneling feature allows you to establish P2P and P2MP TE tunnels spanning multiple
Interior Gateway Protocol (IGP) areas and levels, thereby eliminating the requirement that headend and tailend
routers reside in a single area.
Interarea support allows the configuration of a TE LSP that spans multiple areas, where its headend and tailend
label switched routers (LSRs) reside in different IGP areas.
Multiarea and Interarea TE are required by the customers running multiple IGP area backbones (primarily
for scalability reasons). This lets you limit the amount of flooded information, reduces the SPF duration, and
lessens the impact of a link or node failure within an area, particularly with large WAN backbones split in
multiple areas.
This figure shows a typical interarea TE network.
Figure 13: Interarea (OSPF) TE Network Diagram

Multiarea Support

Multiarea support allows an area border router (ABR) LSR to support MPLS-TE in more than one IGP area.
A TE LSP is still confined to a single area.
Multiarea and Interarea TE are required when you run multiple IGP area backbones. The Multiarea and
Interarea TE allows you to:
• Limit the volume of flooded information.
Interarea Support, on page 181
Multiarea Support, on page 181
Loose Hop Expansion, on page 182
Loose Hop Reoptimization, on page 183
Fast Reroute Node Protection, on page 183
Cisco IOS XR MPLS Configuration Guide for the Cisco CRS Router, Release 5.1.x
MPLS Traffic Engineering Interarea Tunneling
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