BFD for IPv6 IS-IS configuration example
Network requirements
As shown in Figure 85, configure IPv6 IS-IS on Switch A and Switch B so that they can reach other.
Enable BFD on VLAN-interface 10 of Switch A and Switch B. After the link between Switch B and the Layer-2 switch fails, BFD can quickly detect the failure and notify IPv6 IS-IS of the failure. Then Switch A and Switch B communicate through Switch C.
Figure 85: Network diagram
![](images/image84.png)
Device | Interface | IPv6 address | Device | Interface | IPv6 address |
Switch A | Vlan-int10 | 2001::1/64 | Switch B | Vlan-int10 | 2001::2/64 |
Vlan-int11 | 2001:2::1/64 | Vlan-int13 | 2001:3::2/64 | ||
Switch C | Vlan-int11 | 2001:2::2/64 | |||
Vlan-int13 | 2001:3::1/64 |
Configuration procedure
Configure IPv6 addresses for interfaces. (Details not shown.)
Configure IPv6 IS-IS:
# Configure Switch A.
<SwitchA> system-view [SwitchA] isis 1 [SwitchA-isis-1] is-level level-1 [SwitchA-isis-1] network-entity 10.0000.0000.0001.00 [SwitchA-isis-1] ipv6 enable [SwitchA-isis-1] quit [SwitchA] interface vlan-interface 10 [SwitchA-Vlan-interface10] isis ipv6 enable 1 [SwitchA-Vlan-interface10] quit [SwitchA] interface vlan-interface 11 [SwitchA-Vlan-interface11] isis ipv6 enable 1 [SwitchA-Vlan-interface11] quit
# Configure Switch B.
<SwitchB> system-view [SwitchB] isis 1 [SwitchB-isis-1] is-level level-1 [SwitchB-isis-1] network-entity 10.0000.0000.0002.00 [SwitchB-isis-1] ipv6 enable [SwitchB-isis-1] quit [SwitchB] interface vlan-interface 10 [SwitchB-Vlan-interface10] isis ipv6 enable 1 [SwitchB-Vlan-interface10] quit [SwitchB] interface vlan-interface 13 [SwitchB-Vlan-interface13] isis ipv6 enable 1 [SwitchB-Vlan-interface13] quit
# Configure Switch C.
<SwitchC> system-view [SwitchC] isis 1 [SwitchC-isis-1] network-entity 10.0000.0000.0003.00 [SwitchC-isis-1] ipv6 enable [SwitchC-isis-1] quit [SwitchC] interface vlan-interface 11 [SwitchC-Vlan-interface11] isis ipv6 enable 1 [SwitchC-Vlan-interface11] quit [SwitchC] interface vlan-interface 13 [SwitchC-Vlan-interface13] isis ipv6 enable 1 [SwitchC-Vlan-interface13] quit
Configure BFD functions:
# Enable BFD and configure BFD parameters on Switch A.
[SwitchA] bfd session init-mode active [SwitchA] interface vlan-interface 10 [SwitchA-Vlan-interface10] isis ipv6 bfd enable [SwitchA-Vlan-interface10] bfd min-transmit-interval 500 [SwitchA-Vlan-interface10] bfd min-receive-interval 500 [SwitchA-Vlan-interface10] bfd detect-multiplier 7 [SwitchA-Vlan-interface10] return
# Enable BFD and configure BFD parameters on Switch B.
[SwitchB] bfd session init-mode active [SwitchB] interface vlan-interface 10 [SwitchB-Vlan-interface10] isis ipv6 bfd enable [SwitchB-Vlan-interface10] bfd min-transmit-interval 500 [SwitchB-Vlan-interface10] bfd min-receive-interval 500 [SwitchB-Vlan-interface10] bfd detect-multiplier 6
Verifying the configuration
# Display BFD session information on Switch A.
<SwitchA> display bfd session Total Session Num: 1 Init Mode: Active IPv6 Session Working Under Ctrl Mode: Local Discr: 1441 Remote Discr: 1450 Source IP: FE80::20F:FF:FE00:1202 (link-local address of VLAN-interface 10 on Switch A) Destination IP: FE80::20F:FF:FE00:1200 (link-local address of VLAN-interface 10 on Switch B) Session State: Up Interface: Vlan10 Hold Time: 2319ms
# Display routes destined for 2001:4::0/64 on Switch A.
<SwitchA> display ipv6 routing-table 2001:4::0 64 Summary Count : 1 Destination: 2001:4::/64 Protocol : ISISv6 NextHop : FE80::20F:FF:FE00:1200 Preference: 15 Interface : Vlan10 Cost : 10
The output shows that Switch A and Switch B communicate through VLAN-interface 10. Then the link over VLAN-interface 10 fails.
# Display routes destined for 2001:4::0/64 on Switch A.
<SwitchA> display ipv6 routing-table 2001:4::0 64 Summary Count : 1 Destination: 2001:4::/64 Protocol : ISISv6 NextHop : FE80::BAAF:67FF:FE27:DCD0 Preference: 15 Interface : Vlan11 Cost : 20
The output shows that Switch A and Switch B communicate through VLAN-interface 11.