Configuring Dual-Link Cold Backup (Traditional Method)

Context

Dual-link cold backup can be configured using either of the following methods:

Global configuration: The dual-link backup parameters are configured in the AC's WLAN view and delivered to all APs except the specified APs. You can use this method to batch enable dual-link backup.
AP-specific configuration: The dual-link backup parameters are configured in the AC's AP system profile view and apply to all APs using the AP system profile. The AP-specific configuration takes precedence over global configuration on the AC.

The following configurations must be performed on both the active and standby ACs.

Pre-configuration Tasks

Before configuring dual-link cold backup, configure basic WLAN services on the active and standby ACs (For details, see WLAN Service Configuration Guide).

Procedure

Global configuration
1. Run system-view
  The system view is displayed.
2. (Optional) Run capwap echo { interval interval-value | times times-value } ^*
  The CAPWAP heartbeat interval and number of CAPWAP heartbeat detections are configured.
  
  By default, the CAPWAP heartbeat detection interval is 25s and the number of CAPWAP heartbeat detections is 6.
  
  By default, If dual-link backup is enabled, the CAPWAP heartbeat detection interval is 25s and the number of CAPWAP heartbeat detections is 3.
  - To configure dual-link backup on a WDS or mesh network, set the CAPWAP heartbeat interval to 25 seconds and set the number of heartbeat packet transmissions to at least 6. If this configuration is not performed, the AC sends heartbeat packets 3 times at an interval of 25 seconds by default. This may cause unstable WDS or mesh link status and result in user access failures.
  - If you set the CAPWAP heartbeat detection interval and the number of CAPWAP heartbeat detections smaller than the default values, the CAPWAP link reliability is degraded. Exercise caution when you set the values. The default values are recommended.
3. Run wlan
  The WLAN view is displayed.
4. Run ac protect protect-ac ip-address
  The IP address of the standby AC is configured.
  
  By default, no standby AC IP address is configured in the WLAN view.
5. Run ac protect priority priority
  The priority of the local AC is configured.
  
  By default, the AC priority in the WLAN view is 0.
  - The priority of the standby AC must be smaller than that of the active AC.
  - A smaller value indicates a higher priority.
6. Run undo ac protect restore disable
  Revertive switching is enabled.
  
  By default, global revertive switching is enabled.
  
  If global revertive switching is disabled on the original active AC, traffic of an AP cannot be switched back to the original active AC when the link between the original active AC and the AP restores.
7. (Optional) Run ac protect cold-backup kickoff-station
  STAs using open system authentication are configured to disconnect from APs when an active/standby AC switchover is implemented.
  
  By default, STAs using open system authentication remain connected to APs when an active/standby AC switchover is implemented.
8. (Optional) Run ac protect alarm-restrain enable
  AP fault alarm suppression is enabled.
  
  By default, AP Fault alarm suppression is disabled.
9. Run ac protect enable
  By default, dual-link backup is disabled.
10. Run ap-reset { all | ap-name ap-name | ap-mac ap-mac | ap-id ap-id | ap-group ap-group | ap-type { type type-name | type-id type-id } }
  APs are restarted to make the dual-link backup configurations take effect.
  - If the dual-link backup function is disabled, running the ac protect enable command restarts online APs. After the APs are restarted, the dual-link backup function takes effect.
  - If the dual-link backup function is enabled, running the ac protect enable command does not restart online APs. You need to run the ap-reset { all | ap-name ap-name | ap-mac ap-mac | ap-id ap-id | ap-group ap-group | ap-type { type type-name | type-id type-id } } command to restart the APs and make the dual-link backup function take effect. You can also manually restart the APs to make the dual-link backup function take effect.
  - If an AP goes online after dual-link backup is configured, you do not need to restart the AP.
AP-specific configuration
1. Run system-view
  The system view is displayed.
2. (Optional) Run capwap echo { interval interval-value | times times-value } ^*
  The CAPWAP heartbeat interval and number of CAPWAP heartbeat detections are configured.
  
  By default, the CAPWAP heartbeat detection interval is 25s and the number of CAPWAP heartbeat detections is 6.
  
  By default, If dual-link backup is enabled, the CAPWAP heartbeat detection interval is 25s and the number of CAPWAP heartbeat detections is 3.
  - To configure dual-link backup on a WDS or mesh network, set the CAPWAP heartbeat interval to 25 seconds and set the number of heartbeat packet transmissions to at least 6. If this configuration is not performed, the AC sends heartbeat packets 3 times at an interval of 25 seconds by default. This may cause unstable WDS or mesh link status and result in user access failures.
  - If you set the CAPWAP heartbeat detection interval and the number of CAPWAP heartbeat detections smaller than the default values, the CAPWAP link reliability is degraded. Exercise caution when you set the values. The default values are recommended.
3. Run wlan
  The WLAN view is displayed.
4. Run ap-system-profile name profile-name
  An AP system profile is created and the AP system profile view is displayed.
  
  By default, the system provides the AP system profile default.
5. Run protect-ac ip-address ip-address
  The IP address of the standby AC is configured.
  
  By default, no standby AC's IP address is configured in the AP system profile view.
6. Run priority priority-level
  The priority of the local AC is configured.
  
  By default, no AC priority is configured in the AP system profile view.
  - The priority of the standby AC must be smaller than that of the active AC.
  - If priorities have been configured for the two ACs to which an AP connects, the AC with higher priority becomes the active AC.
7. Run quit
  Return to the WLAN view.
8. Run undo ac protect restore disable
  Revertive switching is enabled.
  
  By default, global revertive switching is enabled.
  
  If global revertive switching is disabled on the original active AC, traffic of an AP cannot be switched back to the original active AC when the link between the original active AC and the AP restores.
9. (Optional) Run ac protect cold-backup kickoff-station
  STAs using open system authentication are configured to disconnect from APs when an active/standby AC switchover is implemented.
  
  By default, STAs using open system authentication remain connected to APs when an active/standby AC switchover is implemented.
10. (Optional) Run ac protect alarm-restrain enable
  AP fault alarm suppression is enabled.
  
  By default, AP Fault alarm suppression is disabled.
11. Run ac protect enable
  By default, dual-link backup is disabled.
12. The AP system profile is bound to an AP group.
  - Binding an AP system profile to an AP group.
    1. Run the ap-group name group-name command to enter the AP group view.
    2. Run the ap-system-profile profile-name command to bind the AP system profile to the AP group.
      
      By default, the AP system profile default is bound to an AP group.
  - Binding an AP system profile to an AP.
    1. Run the ap-id ap-id, ap-mac ap-mac, or ap-name ap-name command to enter the AP view.
    2. Run the ap-system-profile profile-name command to bind the AP system profile to the AP.
      
      By default, no AP system profile is bound to an AP.
13. Run quit
  Return to the WLAN view.
14. Run ap-reset { all | ap-name ap-name | ap-mac ap-mac | ap-id ap-id | ap-group ap-group | ap-type { type type-name | type-id type-id } }
  APs are restarted to make the dual-link backup configurations take effect.
  - If the dual-link backup function is disabled, running the ac protect enable command restarts online APs. After the APs are restarted, the dual-link backup function takes effect.
  - If the dual-link backup function is enabled, running the ac protect enable command does not restart online APs. You need to run the ap-reset { all | ap-name ap-name | ap-mac ap-mac | ap-id ap-id | ap-group ap-group | ap-type { type type-name | type-id type-id } } command to restart the APs and make the dual-link backup function take effect. You can also manually restart the APs to make the dual-link backup function take effect.
  - If an AP goes online after dual-link backup is configured, you do not need to restart the AP.

Verifying the Configuration

Run the display ac protect command to check the dual-link backup status, active/standby AC switch back status, as well as AC priority and the standby AC's IP address in the WLAN view.
Run the display ap-system-profile { all | name profile-name } command to check the AC priority and the standby AC's IP address in the AP system profile view.