BFD for static routes configuration example (indirect next hop)
Network requirements
As shown in Figure 5, Switch A has a route to interface Loopback 1 (2.2.2.9/32) on Switch B, with output interface VLAN-interface 10. Switch B has a route to interface Loopback 1 (1.1.1.9/32) on Switch A, with output interface VLAN-interface 12. Switch D has a route to 1.1.1.9/32, with output interface VLAN-interface 10, and a route to 2.2.2.9/32, with output interface VLAN-interface 12.
Configure static routes to subnet 120.1.1.0/24 on Switch A, static routes to subnet 121.1.1.0/24 on Switch B, and static routes to subnets 120.1.1.0/24 and 121.1.1.0/24 on both Switch C and Switch D. Enable BFD so that when the link between Switch A and Switch B through Switch D fails, BFD can detect the failure immediately and Switch A and Switch B can communicate through Switch C.
Figure 5: Network diagram
Device | Interface | IP address | Device | Interface | IP address |
|---|---|---|---|---|---|
Switch A | Vlan-int10 | 12.1.1.1/24 | Switch B | Vlan-int12 | 11.1.1.1/24 |
Vlan-int11 | 10.1.1.102/24 | Vlan-int13 | 13.1.1.1/24 | ||
Loop1 | 1.1.1.9/32 | Loop1 | 2.2.2.9/32 | ||
Switch C | Vlan-int11 | 10.1.1.100/24 | Switch D | Vlan-int10 | 12.1.1.2/24 |
Vlan-int13 | 13.1.1.2/24 | Vlan-int12 | 11.1.1.2/24 |
Configuration procedure
Configure IP addresses for the interfaces. (Details not shown.)
Configure static routes and BFD:
# Configure static routes on Switch A and enable BFD control mode for the static route that traverses Switch D.
<SwitchA> system-view [SwitchA] interface loopback 1 [SwitchA-LoopBack1] bfd min-transmit-interval 500 [SwitchA-LoopBack1] bfd min-receive-interval 500 [SwitchA-LoopBack1] bfd detect-multiplier 9 [SwitchA-LoopBack1] quit [SwitchA] ip route-static 120.1.1.0 24 2.2.2.9 bfd control-packet bfd-source 1.1.1.9 [SwitchA] ip route-static 120.1.1.0 24 vlan-interface 11 10.1.1.100 preference 65 [SwitchA] quit
# Configure static routes on Switch B and enable BFD control mode for the static route that traverses Switch D.
<SwitchB> system-view [SwitchB] interface loopback 1 [SwitchB-LoopBack1] bfd min-transmit-interval 500 [SwitchB-LoopBack1] bfd min-receive-interval 500 [SwitchB-LoopBack1] bfd detect-multiplier 9 [SwitchB-LoopBack1] quit [SwitchB] ip route-static 121.1.1.0 24 1.1.1.9 bfd control-packet bfd-source 2.2.2.9 [SwitchB] ip route-static 121.1.1.0 24 vlan-interface 13 13.1.1.2 preference 65 [SwitchB] quit
# Configure static routes on Switch C.
<SwitchC> system-view [SwitchC] ip route-static 120.1.1.0 24 vlan-interface 13 13.1.1.1 [SwitchC] ip route-static 121.1.1.0 24 vlan-interface 11 10.1.1.102
# Configure static routes on Switch D.
<SwitchD> system-view [SwitchD] ip route-static 120.1.1.0 24 vlan-interface 12 11.1.1.1 [SwitchD] ip route-static 121.1.1.0 24 vlan-interface 10 12.1.1.1
Verify the configuration:
# Display the BFD session information on Switch A.
<SwitchA> display bfd session Total Session Num: 1 Init Mode: Active Session Working Under Ctrl Mode: LD/RD SourceAddr DestAddr State Holdtime Interface 4/7 1.1.1.9 2.2.2.9 Up 2000ms Loop1
The output shows that the BFD session has been created.
# Display static routes on Switch A.
<SwitchA> display ip routing-table protocol static Public Routing Table : Static Summary Count : 2 Static Routing table Status : <Active> Summary Count : 1 Destination/Mask Proto Pre Cost NextHop Interface 120.1.1.0/24 Static 60 0 2.2.2.9 Vlan10 Static Routing table Status : <Inactive> Summary Count : 1 Destination/Mask Proto Pre Cost NextHop Interface 120.1.1.0/24 Static 65 0 10.1.1.100 Vlan11
The output shows that Switch A communicates with Switch B through VLAN-interface 10.
When the link over VLAN-interface 10 fails, Switch A can quickly detect the failure.
# Display static routes on Switch A again.
<SwitchA> display ip routing-table protocol static Public Routing Table : Static Summary Count : 1 Static Routing table Status : <Active> Summary Count : 1 Destination/Mask Proto Pre Cost NextHop Interface 120.1.1.0/24 Static 65 0 10.1.1.100 Vlan11 Static Routing table Status : <Inactive> Summary Count : 0
The output shows that Switch A communicates with Switch B through VLAN-interface 11 now.