SR-MPLS TE Policy Failover
SBFD for SR-MPLS TE Policy checks the connectivity of segment lists. If a segment list is faulty, an SR-MPLS TE Policy failover is triggered.
On the networks shown in Figure 1 and Figure 2, the headend and endpoint of SR-MPLS TE Policy 1 are PE1 and PE2, respectively. In addition, the headend and endpoint of SR-MPLS TE Policy 2 are PE1 and PE3, respectively. VPN FRR can be deployed for SR-MPLS TE Policy 1 and SR-MPLS TE Policy 2. Primary and HSB paths are established for SR-MPLS TE Policy 1. Segment list 1 contains node labels to P1, P2, and PE2. It can directly use all protection technologies of SR-MPLS, for example, TI-LFA.
In Figure 1:
- If point 1, 3, or 5 is faulty, TI-LFA local protection takes effect only on PE1, P1, or P2. If the SBFD session corresponding to segment list 1 on PE1 detects a fault before traffic is restored through local protection, SBFD automatically sets segment list 1 to down and instructs SR-MPLS TE Policy 1 to switch to segment list 2.
- If point 2 or 4 is faulty, no local protection is available. SBFD detects node faults, sets segment list 1 to down, and instructs SR-MPLS TE Policy 1 to switch to segment list 2.
- If PE2 is faulty and all the candidate paths of SR-MPLS TE Policy 1 are unavailable, SBFD can detect the fault, set SR-MPLS TE Policy 1 to down, and trigger a VPN FRR switchover to switch traffic to SR-MPLS TE Policy 2.