Detailed Cisco Unified CM CNF Functionality

The change notification capability supports all the objects that are available via AXL.  In general, this means that everything VOSS-4-UC can manage in Cisco Unified CM will be available via change notification.

Data that VOSS-4-UC pulls from Cisco Unified CM that is not via AXL, includes:

  • device/cucm/PhoneType - this is a combination of thinAXL so would not auto-update.  This includes when you add or update phone types in Cisco Unified CM with COP files or via Cisco Unified CM upgrades.  So a non-CNF sync is still required for this model.
  • Phone Status and IP Address - this is pulled into the system when the phones are viewed in VOSS-4-UC (list view or individual phone).  This is not via AXL so would not be updated via change notification or even a normal sync at this point.

In Cisco Unified CM, the change queue cache is stored in memory and is limited to 100,000 changes. The cache can fill quickly depending on the types of changes performed. For example, if an XSI (IP Phone) Service has been configured for 10,000 phones and the service is deleted, the cache will include one entry representing the deletion of the service plus 10,000 phone updates indicating the service was removed from each device. The polling period from the Cisco Unified CM is configurable and the timing should be considered based on how frequent configuration changes are being made in Cisco Unified CM.  The default in VOSS-4-UC when polling is enabled is 300 seconds but it can be modified to be longer (up to 7200 seconds) as desired.

Cisco Unified CM Setup to use CNF

There are two settings in the Cisco Unified CM to check and update to ensure Change Notification is enabled and set up for the right queue size (accessed via service parameters: - System > Service Parameters > Cisco Database Layer Monitor then click the Advanced button):

Service Parameter Name Setting
AXL Change Notification This should be set to “On”
AXL Change Notification Queue Size This has a default of 20000.  For a typical system, it is suggested this is changed to the maximum of 100000 to reduce the chance of changes being missed under heavy provisioning tasks.