License Application: How Do I Configure Licenses for ACs in Backup Mode?

• For V200R005C10 and earlier versions, license synchronization between the active and standby ACs is not supported in any backup mode. The following table lists license deployment policies in different backup modes.

  Backup Mode		License Deployment Policy
  HSB	Dual-link HSB (load balancing mode)	Apply for and load the license for the active and standby ACs separately. Each of the two licenses must meet the requirement for the AP quantity.
  	Dual-link HSB (active/standby mode)
  	VRRP HSB
  Dual-link cold backup
  N+1 backup		Apply for and load the license for each AC separately. Ensure that the number of APs supported by the license of the backup AC is not less than that supported by the license of any master AC. In this way, if any master AC fails, all APs on the faulty master AC can be switched to the backup AC.

• For V200R006C10 and later versions, license synchronization between ACs is supported in specific backup modes. Through license synchronization, license resources loaded on an AC can be synchronized to another AC. Then the total number of license resources on an AC is the sum of that on itself and that synchronized from other ACs. The following table lists license deployment policies in different backup modes.

  Backup Mode		License Deployment Policy
  HSB	Dual-link HSB (load balancing mode)	License synchronization between the active and standby ACs is supported. Licenses on the active and standby ACs can be backed up to each other. In dual-link HSB and dual-link cold backup scenarios, a license is synchronized between the active and standby ACs when APs go online. In VRRP HSB scenarios, a license can be automatically synchronized between the active and standby ACs regardless of whether APs go online. You are advised to apply for and load a license for the active AC. Then the license will be synchronized to the standby AC. From V200R006C10 to V200R008C10, run the display ap-backup-license command in the diagnostic view to check information about the backup license. For V200R009C00 and later versions, run the display license resource usage command in any view to check information about the backup license. NOTE: Only the ESN of the active AC is required when you apply for a license. If a license is loaded on the active AC before AC backup is configured, the license will be backed up to the standby AC. In dual-link HSB (load balancing) scenarios, ensure that the number of license resources loaded on ACs is no less than the total number of APs managed by the active and standby ACs. Otherwise, a fault of the active AC may cause some APs to fail to go online due to insufficient licenses.
  	Dual-link HSB (active/standby mode)
  	VRRP HSB
  Dual-link cold backup
  N+1 backup		From V200R006C10 to V200R008C10: License synchronization between the master and backup ACs is not supported. Apply for and load the license for each AC separately. Ensure that the number of APs supported by the license of the backup AC is not less than that supported by the license of any master AC. In this way, if any master AC fails, all APs on the faulty master AC can be switched to the backup AC. For V200R009C00 and later versions: Licenses on master ACs can be synchronized to the backup AC. The synchronization, however, is triggered only when APs go online. Licenses on the backup AC cannot be synchronized to master ACs. You are advised to apply for and load licenses for the master ACs. The license will be automatically backed up to the standby AC. Run the display license resource usage command in any view to check information about the backup license. NOTE: Only the ESN of the active AC is required when you apply for a license. If a license is loaded on the active AC before AC backup is configured, the license will be backed up to the standby AC.

• For V200R010C00 and later versions, if two or more ACs are deployed, the centralized license control function can be used. In centralized license control mode, one AC functions as the license server to manage all license resources, while the other ACs function as license clients to report local license resources to the license server. When an AP goes online on an AC, the license server allocates a license to the AP. When an AP goes offline from an AC, the license server releases the AP license. Centralized license control achieves unified management and flexible allocation of licenses on the network, making license usage easier and more efficient.

  The centralized license control function and license backup function are mutually exclusive. After the centralized license control function is configured, the license backup function becomes invalid.

  Centralized license control applies to various multi-AC networking scenarios as follows:

  Dual-link scenario: includes dual-link HSB and dual-link cold backup scenarios. You can specify any AC as the license server and the other ACs as license clients.

  Wireless configuration synchronization scenario: include VRRP HSB and dual-link HSB scenarios. In the VRRP HSB scenario, the two ACs must be both license servers or license clients. In the dual-link HSB scenario, the local AC automatically functions as the license client, and the master AC automatically functions as the license server.

  Navi AC scenario: You can specify any AC as the license server and the other ACs as license clients. The Navi AC function requires license resources of four APs. Therefore, when applying for a license based on the number of managed APs, you need to add resources of four APs.

  N+1 backup scenario: It is recommended that the backup AC be configured as the license server and master ACs be configured as license clients.

  Scenario where N+1 backup and VRRP HSB are both enabled: The backup AC with VRRP configured functions as the license server, and uses the VRRP virtual IP address to communicate with license clients. Master ACs with VRRP configured function as license clients, and use their real IP addresses to communicate with the license server.

In V200R009C00 and later versions, as shown in Figure 1 where N+1 backup and VRRP HSB are both enabled, AC_1 and AC_1b, and AC_2 and AC_2b form two VRRP groups to serve as the primary ACs in N+1 backup, and AC_3 and AC_3b form a VRRP group to serve as the backup AC in N+1 backup. AC_1, AC_2, and AC_3 are running properly, whose VRRP priorities are higher than those of AC_1b, AC_2b, and AC_3b, respectively.

Figure 1 Networking enabled with both N+1 backup and VRRP HSB

In normal cases, licenses on AC_1 and AC_2 can be synchronized to AC_3, but those on AC_1b and AC_2b cannot. If AC_1 is faulty, AC_1b becomes the working AC and synchronizes its local license to AC_3. License resources that are synchronized from AC_1 to AC_3 enter the grace period (30 days).

For example, there are 384 local license resources on an active ACU2 before it loads a license. The standby ACU2 has no additional license loaded, that is, there are 128 license resources (default) on the standby ACU2. After license synchronization is completed, there are both 512 (384 + 128) license resources on the active and standby ACU2 cards.

The total number of available license resource items cannot exceed the maximum number of resource items supported by an AC.

For the default number of resources before a license is loaded on the AC, see Other: How Are License Resource Items Accumulated?.

For V200R006C20 and earlier versions, if the active AC fails in a backup scenario, standby licenses on the standby AC can still be used. However, the licenses become invalid after the AC is restarted.

From V200R007C10, if the active AC is faulty, the backup license on the standby AC enters the 30-day grace period. The license becomes invalid automatically after 30 days. If the active AC recovers from the fault during the grace period, the grace period will expire. If the active AC becomes faulty again, the backup license re-enters the 30-day grace period.

If the standby AC loads a new license during the grace period, the standby AC can use both the backup and new licenses. After the 30-day grace period, only the new license is available for the standby AC.