HP FlexNetwork 10500 Series Configuration Manual page 209

VPNv4 route backup for an IPv4 route
Figure 61 Network diagram
VPN 1
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.
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
Figure 62 Network diagram
VPN 1
As shown in
VPN 1 as CE 2. 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 VPNv4 route as the primary link,
and the IPv4 route as the backup link.
Configure BFD for LSPs or MPLS TE tunnels on PE 2 to detect the connectivity of the public tunnel
from PE 2 to PE 3. When the tunnel operates correctly, traffic from CE 1 to CE 2 goes through the
path CE 1—PE 1—PE 2—PE 3—CE 2. When the tunnel fails, the traffic goes through the path CE
1—PE 1—PE 2—CE 2.
In this scenario, PE 2 is responsible for primary link detection and traffic switchover.
PE 1
CE 1
Figure 61, configure FRR on the egress node PE 2, and specify the backup next hop for
PE 1
CE 1
Figure 62, configure FRR on the egress node PE 2, and specify the backup next hop for
PE 2
MPLS
backbone
PE 3
PE 2
MPLS
backbone
PE 3
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VPN 1
CE 2
Primary link
Backup link
VPN 1
CE 2
Primary link
Backup link