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Backup between two VPNv4 routes
Figure 83 Backup between two VPNv4 routes
Configure FRR on PE 1 and specify the backup next hop to reach CE 2 as PE 3. When PE 1 receives
a VPNv4 route to CE 2 from both PE 2 and PE 3, it uses the route from PE 2 as the primary route,
and the route from PE 3 as the backup route.
Backup between one IPv4 route and one VPNv4 route
Figure 84 Backup between one IPv4 route and one VPNv4 route
As shown in
, configure FRR on the egress node PE 2 and specify the backup next hop to
reach CE 2 as PE 3. When PE 2 receives an IPv4 route from CE 2 and a VPNv4 route from PE 3
(both routes are destined to VPN 1 connected to CE 2), PE 2 uses the IPv4 route as the primary
route, and the VPNv4 route as the backup route.
Configure echo-mode BFD on PE 2 to detect the link from PE 2 to CE 2. When the link is available,
traffic from CE 1 to CE 2 takes the path CE 1—PE 1—PE 2—CE 2. When the link fails, PE 2 switches
fast to the link PE 2—PE 3—CE 2, and traffic from CE 1 to CE 2 takes the path CE 1—PE 1—PE
2—PE 3—CE 2. This avoids traffic forwarding interruption before route convergence (switching back
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.
Multi-VPN-instance CE
BGP/MPLS VPN transmits private network data through MPLS tunnels over the public network.
However, the traditional MPLS L3VPN architecture requires that each VPN instance use an
exclusive CE to connect to a PE, as shown in