Configure Backup Routing on Tenant VRF

You can enable backup routing when all the links from a leaf device to the spine layer are down, and tenant traffic is to be routed via the MCT neighbor.

About this task

Follow this procedure to configure backup routing on tenant VRF.

A pair of IPv4 and IPv6 address is allocated to each MCT pair across all the tenant VRFs, and the BGP session is established between the same IP Pair.

Procedure

Allocate a pair of IPv4 and IPv6 address to each MCT pair across all the tenant VRFs.
1. Allocate a bridge domain per VRF for backup routing.
2. Allocate a corresponding router-interface VE per BD or VRF.
3. Assign the IPv4 and IPv6 address allocated to each device on each of the VE interface.
  
  Note
  Same IPv4 and IPv6 address is allocated on each of the VE interface which belongs to different VRF.
4. Establish IBGP IPv4 neighborship with the MCT peer on a set of IP address per VRF.
5. Establish IBGP IPv6 neighborship with the MCT peer on a set of IPv6 address per VRF.
6. Configure "next-hop-self" on both the IPv4 and IPv6 neighbor.
7. Configure "active" on the IPv6 neighbor.
Example:
```
efa fabric setting update --name fabric1
--backup-routing-ipv4-range 21.1.1.0/24 --backup-routing-ipv6-range 2001:21:1:1::0/120
```
Example when backup routing is enabled:
```
efa fabric setting update --name nc --backup-routing-enable yes
```

Configure devices on tenant VRFs.

The following table provides an example of device configuration on a tenant VRF:

Table 1. Tenant1 VRF “vrf1”
leaf-9250-173# show running-config bridge-domain 3001 bridge-domain 3001 p2mp pw-profile default router-interface Ve 7001 bpdu-drop-enable ! leaf-9250-173# sh run in ve 7001 interface Ve 7001 vrf forwarding vrf1 ip address 21.1.1.10/31 ipv6 address 2001:21:1:1::10/127 no shutdown !	leaf-9250-173# show running-config router bgp address-family ipv4 unicast vrf vrf1 router bgp address-family ipv4 unicast vrf vrf1 local-as 4210000001 redistribute connected neighbor 21.1.1.11 remote-as 4210000001 neighbor 21.1.1.11 next-hop-self maximum-paths 2 ! ! leaf-9250-173# show running-config router bgp address-family ipv6 unicast vrf vrf1 router bgp address-family ipv6 unicast vrf vrf1 redistribute connected neighbor 2001:21:1:1::11 next-hop-self neighbor 2001:21:1:1::11 remote-as 4210000001 neighbor 2001:21:1:1::11 activate maximum-paths 2 ! !

Table 1. Tenant1 VRF “vrf1”

leaf-9250-173# show running-config bridge-domain 3001
bridge-domain 3001 p2mp
 pw-profile default
 router-interface Ve 7001
 bpdu-drop-enable
!

leaf-9250-173# sh run in ve 7001
interface Ve 7001 
 vrf forwarding vrf1
 ip address 21.1.1.10/31
 ipv6 address 2001:21:1:1::10/127
 no shutdown
!

leaf-9250-173# show running-config router bgp address-family ipv4 unicast vrf vrf1
router bgp
 address-family ipv4 unicast vrf vrf1
  local-as 4210000001
  redistribute connected
  neighbor 21.1.1.11 remote-as 4210000001
  neighbor 21.1.1.11 next-hop-self
  maximum-paths 2
 !
!

leaf-9250-173# show running-config router bgp address-family ipv6 unicast vrf vrf1
router bgp
 address-family ipv6 unicast vrf vrf1
  redistribute connected
  neighbor 2001:21:1:1::11 next-hop-self
  neighbor 2001:21:1:1::11 remote-as 4210000001
  neighbor 2001:21:1:1::11 activate
  maximum-paths 2
 !
!

Table 2. Tenant2 VRF “vrf2”
leaf-9250-173# show running-config bridge-domain 3002 bridge-domain 3002 p2mp pw-profile default router-interface Ve 7002 bpdu-drop-enable ! leaf-9250-173# sh run in ve 7002 interface Ve 7002 vrf forwarding vrf2 ip address 21.1.1.10/31 ipv6 address 2001:21:1:1::10/127 no shutdown !	leaf-9250-173# show running-config router bgp address-family ipv4 unicast vrf vrf2 router bgp address-family ipv4 unicast vrf vrf2 local-as 4210000001 redistribute connected neighbor 21.1.1.11 remote-as 4210000001 neighbor 21.1.1.11 next-hop-self maximum-paths 2 ! ! leaf-9250-173# show running-config router bgp address-family ipv6 unicast vrf vrf2 router bgp address-family ipv6 unicast vrf vrf2 redistribute connected neighbor 2001:21:1:1::11 next-hop-self neighbor 2001:21:1:1::11 remote-as 4210000001 neighbor 2001:21:1:1::11 activate maximum-paths 2 ! !

Table 2. Tenant2 VRF “vrf2”

leaf-9250-173# show running-config bridge-domain 3002
bridge-domain 3002 p2mp
 pw-profile default
 router-interface Ve 7002
 bpdu-drop-enable
!

leaf-9250-173# sh run in ve 7002
interface Ve 7002 
 vrf forwarding vrf2
 ip address 21.1.1.10/31
 ipv6 address 2001:21:1:1::10/127
 no shutdown
!

leaf-9250-173# show running-config router bgp address-family ipv4 unicast vrf vrf2
router bgp
 address-family ipv4 unicast vrf vrf2
  local-as 4210000001
  redistribute connected
  neighbor 21.1.1.11 remote-as 4210000001
  neighbor 21.1.1.11 next-hop-self
  maximum-paths 2
 !
!

leaf-9250-173# show running-config router bgp address-family ipv6 unicast vrf vrf2
router bgp
 address-family ipv6 unicast vrf vrf2
  redistribute connected
  neighbor 2001:21:1:1::11 next-hop-self
  neighbor 2001:21:1:1::11 remote-as 4210000001
  neighbor 2001:21:1:1::11 activate
  maximum-paths 2
 !
!