Do not mass provision devices (>30 units) in one go. Users often made a mistake by displaying more than 30 devices on a page, selecting all devices in Zero Config, and clicking on ‘Update Config’ button. This is not recommended as UCM will consume more time to process and send SIP NOTIFY to each IP phone. This entire process might take several minutes to a few hours, depending on the number of your devices. Do perform provisioning by batch, with each batch consisting of 30 devices.
Do not click on ‘Update’ icon every so often on one particular device. Spamming ‘Update’ will add tons of loads to the UCM and might result in a longer provisioning time for the device. Click once or twice will do.
After clicking on ‘Update Config’ button or ‘Update’ icon, check if there is a new date/time stamp generated on the ‘CREATE CONFIG’ column. If the provisioning success, there should be a new date/time stamp on this column.
If (3) is performed but there is no new date/ time stamp being generated, it means that the provisioning might have failed. We will then proceed to check if the device’s IP address is included under UCM web UI > Other Features > Zero Config Settings > Network Settings > Subnet Whitelist.
If we have confirmed that the device’s IP address is in the subnet whitelist, we will proceed to check from the device’s side (IP Phone). Make sure that ‘Use Random Port’ is set to ‘No’. Certain phone models have this setting configured to ‘Yes’ as default. If ‘Use Random Port’ is set to ‘Yes’, what happens is that the UCM will not be able to send SIP NOTIFY to the phone’s correct port and zero config will fail. However, if we try to have the phone requests the config from UCM’s zero config, it will work. But still, it is a good practice to have ‘Use Random Port’ set to ‘No’.
