Using Frr To Protect P2Mp Te Links - Cisco ASR 920 Series Configuration

Using FRR to Protect P2MP TE Links

• Tunnel bandwidth is configured the same way in both P2P and P2MP tunnels. In P2MP TE tunnels, any
• Tunnel setup and hold priorities, attributes flags, affinity and mask, and administrative weight parameters
• FRR-enabled P2MP sub-LSPs coexist with FRR-enabled P2P LSPs in a network. For P2P TE, node,
• The method of computing the path dynamically through CSPF is the same for P2P and P2MP TE.
• Auto-tunnel backup behaves slightly different with P2P and P2MP tunnels. With P2P tunnels, auto-tunnel
If P2MP sub-LSPs are signaled from R1->R2->R3 and a P2P tunnel is signaled from R3->R2->R1, then
Note
issue the command on R3 in IGP configuration mode under router OSPF or IS-IS to ensure to accommodate
multicast traffic for R3's sub-LSPs.
Using FRR to Protect P2MP TE Links
FRR applies to P2P LSPs and P2MP sub-LSPs in the same manner. No new protocol extensions are needed
to support P2MP.
For P2MP TE FRR protection, issue the command on every penultimate hop router. Otherwise, the router
Note
can lose up to 6 seconds worth of traffic during a FRR cutover event.
FRR minimizes interruptions in traffic delivery as a result of link failure. FRR temporarily fast switches LSP
traffic to a backup path around a network failure until the headend router signals a new end-to-end LSP.
FRR-enabled P2MP sub-LSPs coexist with FRR-enabled P2P LSPs in a network. For P2MP TE, only link
protection is supported. .
You can configure P2P explicit backup tunnels on point of local repair (PLR) nodes for link protection of
P2MP sub-LSPs, similar to LSPs for P2P TE tunnels. You can also enable automatic creation of backup
tunnels using the Auto-tunnel Backup feature for P2P TE tunnels. All sibling sub-LSPs that share the same
outgoing link are protected by the same backup tunnel. All cousin sub-LSPs that share the same outgoing link
can be protected by multiple P2P backup tunnels.
Link protection for a P2MP TE tunnel is illustrated in the figure below, which shows PE1 as the tunnel headend
router and PE2, PE3, and PE4 as tunnel tailend routers. The following sub-LSPs are signaled from PE1 in the
network:
• From PE1 to PE2, the sub-LSP travels the following path: PE1 -> P01 -> P02 -> PE2
MPLS Traffic Engineering Path Calculation and Setup Configuration Guide, Cisco IOS XE Release 3S (Cisco
ASR 920 Series)
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bandwidth parameters you configure are applied to all the destination routers. That is, the bandwidth
parameters apply to all sub-LSPs. Both P2P and P2MP TE tunnels use the same IGP extension to flood
link bandwidth information throughout the network.
are configured the same way for P2P and P2MP TE tunnels. P2MP TE tunnel parameters apply to all
sub-LSPs.
link, and bandwidth protection is supported.
backup creates two backup tunnels: one for the node protection and one for the link protection. The node
protection backup is preferred for P2P LSP protection. With P2MP tunnels, auto-tunnel backup creates
one backup tunnel, which is the link protection. Only the link protection backup can be used for P2MP
sub-LSPs. The P2P and P2MP tunnels can coexist and be protected.
MPLS Point-to-Multipoint Traffic Engineering