Configuring BFD for IS-IS
Network requirements
As shown in Figure 70, IS-IS is enabled on Switch A, Switch B and Switch C that are reachable to each other at the network layer.
After the link over which Switch A and Switch B communicate through the Layer-2 switch fails, BFD can quickly detect the failure and notify IS-IS of the failure. Switch A and Switch B then communicate through Switch C.
Figure 70: Network diagram for BFD configuration on an IS-IS link
Device | Interface | IP address | Device | Interface | IP address |
|---|---|---|---|---|---|
Switch A | Vlan-int10 | 10.1.0.102/24 | Switch B | Vlan-int10 | 10.1.0.100/24 |
Vlan-int11 | 11.1.1.1/24 | Vlan-int13 | 13.1.1.1/24 | ||
Switch C | Vlan-int11 | 11.1.1.2/24 | |||
Vlan-int13 | 13.1.1.2/24 |
Configuration procedure
Configure IP addresses for interfaces (Details not shown.).
Configure IS-IS basic functions.
# Configure Switch A.
<SwitchA> system-view [SwitchA] isis [SwitchA-isis-1] network-entity 10.0000.0000.0001.00 [SwitchA-isis-1] quit [SwitchA] interface vlan-interface 10 [SwitchA-Vlan-interface10] isis enable [SwitchA-Vlan-interface10] quit [SwitchA] interface vlan-interface 11 [SwitchA-Vlan-interface11] isis enable [SwitchA-Vlan-interface11] quit
# Configure Switch B.
<SwitchB> system-view [SwitchB] isis [SwitchB-isis-1] network-entity 10.0000.0000.0002.00 [SwitchB-isis-1] quit [SwitchB] interface vlan-interface 10 [SwitchB-Vlan-interface10] isis enable [SwitchB-Vlan-interface10] quit [SwitchB] interface vlan-interface 13 [SwitchB-Vlan-interface13] isis enable [SwitchB-Vlan-interface13] quit
# Configure Switch C.
<SwitchC> system-view [SwitchC] isis [SwitchC-isis-1] network-entity 10.0000.0000.0003.00 [SwitchC-isis-1] quit [SwitchC] interface vlan-interface 11 [SwitchC-Vlan-interface11] isis enable [SwitchC-Vlan-interface11] quit [SwitchC] interface vlan-interface 13 [SwitchC-Vlan-interface13] isis enable [SwitchC-Vlan-interface13] quit
Configure BFD parameters:
# Enable BFD on Switch A and configure BFD parameters.
[SwitchA] bfd session init-mode active [SwitchA] interface vlan-interface 10 [SwitchA-Vlan-interface10] isis bfd enable [SwitchA-Vlan-interface10] bfd min-receive-interval 500 [SwitchA-Vlan-interface10] bfd min-transmit-interval 500 [SwitchA-Vlan-interface10] bfd detect-multiplier 7
# Enable BFD on Switch B and configure BFD parameters.
[SwitchB] bfd session init-mode active [SwitchB] interface vlan-interface 10 [SwitchB-Vlan-interface10] isis bfd enable [SwitchB-Vlan-interface10] bfd min-receive-interval 500 [SwitchB-Vlan-interface10] bfd min-transmit-interval 500 [SwitchB-Vlan-interface10] bfd detect-multiplier 8 [SwitchB-Vlan-interface10] return
Verify the configuration:
# Display the BFD 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 3/1 10.1.0.102 10.1.0.100 Up 1700ms vlan10
# Display routes destined for 120.1.1.0/24 on Switch A.
<SwitchA> display ip routing-table 120.1.1.0 verbose Routing Table : Public Summary Count : 1 Destination: 120.1.1.0/24 Protocol: ISIS Process ID: 1 Preference: 0 Cost: 2 IpPrecedence: QosLcId: NextHop: 192.168.0.100 Interface: Vlan-interface10 BkNextHop: 0.0.0.0 BkInterface: RelyNextHop: 0.0.0.0 Neighbor : 0.0.0.0 Tunnel ID: 0x0 Label: NULL BKTunnel ID: 0x0 BKLabel: NULL State: Active Adv Age: 00h58m10s Tag: 0The output shows that Switch A communicates with Switch B through VLAN-interface 10.
When the link over VLAN-interface 10 fails, BFD can quickly detect the failure.
# Display the BFD information on Switch A.
<SwitchA> display bfd session
Switch A has deleted the BFD session on VLAN-interface 10 to Switch B and displays no output.
# Display routes destined for 120.1.1.0/24 on Switch A.
<SwitchA> display ip routing-table 120.1.1.0 verbose Routing Table : Public Summary Count : 1 Destination: 120.1.1.0/24 Protocol: ISIS Process ID: 1 Preference: 10 Cost: 4 IpPrecedence: QosLcId: NextHop: 10.1.1.100 Interface: Vlan-interface11 BkNextHop: 0.0.0.0 BkInterface: RelyNextHop: 0.0.0.0 Neighbor : 0.0.0.0 Tunnel ID: 0x0 Label: NULL BKTunnel ID: 0x0 BKLabel: NULL State: Active Adv Age: 00h58m10s Tag: 0The output shows that Switch A communicates with Switch B through VLAN-interface 11.