BFD for static routes configuration example (indirect next hop)
Network requirements
Figure 4 shows the network topology as follows:
Switch A has a route to interface Loopback 1 (2.2.2.9/32) on Switch B, with the output interface VLAN-interface 10.
Switch B has a route to interface Loopback 1 (1.1.1.9/32) on Switch A, with the output interface VLAN-interface 12.
Switch D has a route to 1.1.1.9/32, with the output interface VLAN-interface 10, and a route to 2.2.2.9/32, with the output interface VLAN-interface 12.
Configure the following:
Configure a static route to subnet 120.1.1.0/24 on Switch A.
Configure a static route to subnet 121.1.1.0/24 on Switch B.
Enable BFD for both routes.
Configure a static route to subnet 120.1.1.0/24 and a static route to subnet 121.1.1.0/24 on both Switch C and Switch D.
When the link between Switch A and Switch B through Switch D fails, BFD can detect the failure immediately. Switch A then communicates with Switch B through Switch C.
Figure 4: Network diagram
Table 5: Interface and IP address assignment
Device | Interface | IP address |
|---|---|---|
Switch A | VLAN-interface 10 | 12.1.1.1/24 |
Switch A | VLAN-interface 11 | 10.1.1.102/24 |
Switch A | Loopback 1 | 1.1.1.9/32 |
Switch B | VLAN-interface 12 | 11.1.1.1/24 |
Switch B | VLAN-interface 13 | 13.1.1.1/24 |
Switch B | Loopback 1 | 2.2.2.9/32 |
Switch C | VLAN-interface 11 | 10.1.1.100/24 |
Switch C | VLAN-interface 13 | 13.1.1.2/24 |
Switch D | VLAN-interface 10 | 12.1.1.2/24 |
Switch D | VLAN-interface 12 | 11.1.1.2/24 |
Configuration procedure
Configure IP addresses for 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] bfd multi-hop min-transmit-interval 500 [SwitchA] bfd multi-hop min-receive-interval 500 [SwitchA] bfd multi-hop detect-multiplier 9 [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] bfd multi-hop min-transmit-interval 500 [SwitchB] bfd multi-hop min-receive-interval 500 [SwitchB] bfd multi-hop detect-multiplier 9 [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 13.1.1.1 [SwitchC] ip route-static 121.1.1.0 24 10.1.1.102
# Configure static routes on Switch D.
<SwitchD> system-view [SwitchD] ip route-static 120.1.1.0 24 11.1.1.1 [SwitchD] ip route-static 121.1.1.0 24 12.1.1.1
Verifying the configuration
# Display BFD sessions on Switch A.
<SwitchA> display bfd session Total Session Num: 1 Up Session Num: 1 Init Mode: Active IPv4 Session Working Under Ctrl Mode: LD/RD SourceAddr DestAddr State Holdtime Interface 4/7 1.1.1.9 2.2.2.9 Up 2000ms N/A
The output shows that the BFD session has been created.
# Display the static routes on Switch A.
<SwitchA> display ip routing-table protocol 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 60 0 12.1.1.2 Vlan10 Static Routing table Status : <Inactive> Summary Count : 0
The output shows that Switch A communicates with Switch B through VLAN-interface 10. Then the link over VLAN-interface 10 fails.
# Display static routes on Switch A.
<SwitchA> display ip routing-table protocol 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.