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Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09
Chapter 34 MPLS Traffic Engineering - Fast Reroute Link Protection
How to Configure Traffic Engineering - Fast Reroute Link Protection
BFD
BFD is a detection protocol designed to provide fast forwarding link failure detection times for all media
types, encapsulations, topologies, and routing protocols. In addition to fast forwarding link failure
detection, BFD provides a consistent failure detection method for network administrators. Because the
network administrator can use BFD to detect forwarding link failures at a uniform rate, rather than the
variable rates for different routing protocol Hello mechanisms, network profiling and planning is easier,
and reconvergence time is consistent and predictable.
Fast Reroute
Fast Reroute is a mechanism for protecting MPLS TE LSPs from link failures by locally repairing the
LSPs at the point of failure. This allows the data to continue to flow on them while their headend routers
attempt to establish new end-to-end LSPs to replace them. FRR locally repairs the protected LSPs by
rerouting them over backup tunnels that bypass failed links.
Link Protection
Backup tunnels that bypass only a single link of the LSP’s path provide link protection. They protect
LSPs if a link along their path fails by rerouting the LSP’s traffic to the next hop (bypassing the failed
link). These are referred to as next-hop (NHOP) backup tunnels because they terminate at the LSP’s next
hop beyond the point of failure.
How to Configure Traffic Engineering - Fast Reroute Link
Protection
This section describes how to configure MPLS TE-FRR Link Protection feature:
• Enabling MPLS TE-FRR on an SVI Interface, page 34-5 (Required)
• Enabling MPLS TE-FRR for EoMPLS on a Global Interface, page 34-5 (Required)
• Enabling MPLS TE-FRR for EoMPLS on an Interface, page 34-7 (Required)
• Enabling MPLS TE-FRR for IS-IS, page 34-9 (Required)
• Configuring Primary One-hop Auto-Tunnels, page 34-11 (Required)
• Configuring Backup Auto-Tunnels, page 34-13 (Required)
• Enabling Targeted LDP session over Primary one-hop Auto-Tunnels, page 34-14 (Required)
• Enabling BFD Triggered FRR on an SVI Interface, page 34-15 (Required)
• Enabling BFD Triggered FRR on a Router, page 34-16 (Required)
• Verifying MPLS TE-FRR Configuration, page 34-17 (Optional)
• Verifying Primary One-hop Auto-Tunnels, page 34-19 (Optional)
• Verifying Backup Auto-Tunnels, page 34-19 (Optional)
• Verifying BFD Triggered FRR Configuration, page 34-20 (Optional)