HP FlexNetwork HSR6600 Configuration Manual page 224

Figure 68 Network diagram
Configure BFD for LSPs or MPLS TE tunnels on PE 1 to detect the connectivity of the public tunnel
from PE 1 to PE 2. When the tunnel PE 1—PE 2 operates correctly, traffic from CE 1 to CE 2 goes
through the path CE 1—PE 1—PE 2—CE 2. When the tunnel fails, the traffic goes through the path
CE 1—PE 1—PE 3—CE 2.
In this scenario, PE 1 is responsible for primary link detection and traffic switchover.
For more information about BFD for LSPs or MPLS TE tunnels, see "Configuring MPLS OAM."
VPNv4 route backup for an IPv4 route
As shown in
VPN 1 as PE 3. When PE 2 receives an IPv4 route from CE 2 and a VPNv4 route from PE 3 (both
routes are destined for VPN 1 connected to CE 2), PE 2 uses the IPv4 route as the primary link, and
the VPNv4 route as the backup link.
Figure 69 Network diagram
PE 2 uses ARP or echo-mode BFD to detect the connectivity of the link from PE 2 to CE 2. When the
link operates correctly, traffic from CE 1 to CE 2 goes through the path CE 1—PE 1—PE 2—CE 2.
When the link fails, PE 2 switches traffic to the link PE 2—PE 3—CE 2, and traffic from CE 1 to CE 2
goes through the path CE 1—PE 1—PE 2—PE 3—CE 2. This avoids traffic interruption before route
convergence completes (switching to the link CE 1—PE 1—PE 3—CE 2).
In this scenario, PE 2 is responsible for primary link detection and traffic switchover.
IPv4 route backup for a VPNv4 route
As shown in
When PE 1 receives an IPv4 route from CE 2 and a VPNv4 route from PE 2 (both routes are destined
Figure 69, configure FRR on the egress node PE 2, and specify the backup next hop for
Figure 70, configure FRR on PE 1, and specify the backup next hop for VPN 1 as CE 2.
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