Configuring MPLS L3VPN FRR through VPNv4 route backup for an IPv4 route
Network requirements
CE 1 and CE 2 belong to VPN 1.
Configure EBGP between CEs and PEs to exchange VPN routes.
Configure OSPF to ensure connectivity between PEs, and configure MP-IBGP to exchange VPNv4 routing information between PEs.
Configure MPLS L3VPN FRR on PE 2 to achieve the following purposes:
When the link PE 2—CE 2 operates correctly, traffic from CE 1 to CE 2 goes through the path CE 1—PE 1—PE 2—CE 2.
When BFD detects that the link between PE 2 and CE 2 fails, traffic from CE 1 to CE 2 goes through the path CE 1—PE 1—PE 2—PE 3—CE 2.
Figure 86: Network diagram
Table 27: Interface and IP address assignment
Device | Interface | IP address | Device | Interface | IP address |
|---|---|---|---|---|---|
CE 1 | Loop0 | 5.5.5.5/32 | PE 2 | Loop0 | 2.2.2.2/32 |
GE2/1/1 | 10.2.1.1/24 | GE2/1/1 | 172.1.1.2/24 | ||
PE 1 | Loop0 | 1.1.1.1/32 | GE2/1/2 | 10.1.1.2/24 | |
GE2/1/1 | 10.2.1.2/24 | GE2/1/3 | 172.3.1.2/24 | ||
GE2/1/2 | 172.1.1.1/24 | PE 3 | Loop0 | 3.3.3.3/32 | |
GE2/1/3 | 172.2.1.1/24 | GE2/1/1 | 172.2.1.3/24 | ||
CE 2 | Loop0 | 4.4.4.4/32 | GE2/1/2 | 10.3.1.2/24 | |
GE2/1/1 | 10.1.1.1/24 | GE2/1/3 | 172.3.1.3/24 | ||
GE2/1/2 | 10.3.1.1/24 |
Configuration procedure
Configure IP addresses and masks for interfaces as shown in Table 27, and configure BGP and MPLS L3VPN. (Details not shown.)
For more information about configuring basic MPLS L3VPN, see "Configuring basic MPLS L3VPN."
Configure MPLS L3VPN FRR on PE 2:
# Configure the source IP address of BFD echo packets as 12.1.1.1.
<PE2> system-view [PE2] bfd echo-source-ip 12.1.1.1
# Create routing policy frr, and specify the backup next hop as 3.3.3.3 for the route to 4.4.4.4/32.
[PE2] ip prefix-list abc index 10 permit 4.4.4.4 32 [PE2] route-policy frr permit node 10 [PE2-route-policy] if-match ip address prefix-list abc [PE2-route-policy] apply fast-reroute backup-nexthop 3.3.3.3 [PE2-route-policy] quit
# Use echo-mode BFD to detect the primary route connectivity.
[PE2] bgp 100 [PE2-bgp-default] primary-path-detect bfd echo
# Configure FRR for VPN instance vpn1 to use routing policy frr.
[PE2-bgp-default] ip vpn-instance vpn1 [PE2-bgp-default-vpn1] address-family ipv4 unicast [PE2-bgp-default-ipv4-vpn1] fast-reroute route-policy frr
# Specify the preferred value as 200 for BGP routes received from CE 2. This value is greater than the preferred value (0) for routes from PE 3, so PE 2 prefers the routes from CE 2.
[PE2-bgp-default-ipv4-vpn1] peer 10.1.1.1 preferred-value 200 [PE2-bgp-default-vpn1] quit [PE2-bgp-default] quit
Verifying the configuration
# Display detailed information about the route to 4.4.4.4/32 on PE 2. The output shows the backup next hop for the route.
[PE2] display ip routing-table vpn-instance vpn1 4.4.4.4 32 verbose
Summary Count : 1
Destination: 4.4.4.4/32
Protocol: BGP instance default
Process ID: 0
SubProtID: 0x2 Age: 01h54m24s
Cost: 0 Preference: 10
IpPre: N/A QosLocalID: N/A
Tag: 0 State: Active Adv
OrigTblID: 0x0 OrigVrf: vpn1
TableID: 0x102 OrigAs: 300
NibID: 0x15000002 LastAs: 300
AttrID: 0x0 Neighbor: 10.1.1.1
Flags: 0x10060 OrigNextHop: 10.1.1.1
Label: NULL RealNextHop: 10.1.1.1
BkLabel: 1275 BkNextHop: 172.3.1.3
Tunnel ID: Invalid Interface: GE2/1/2
BkTunnel ID: 0x409 BkInterface: GE2/1/3
FtnIndex: 0x0 TrafficIndex: N/A
Connector: N/A