what do you mean by: "phones cannot log into SUB"?

do you mean the phones are not failing over for call control to the SUB??

have you configured the CCM group with the two servers? PUB then SUB? is this the CCM group the phones are using?

if this is the issue please try the following:

For the test you want to do please verify the following:

1) You have both servers properly configured in CCM Admin

System -> Cisco CallManager -> Click on Find button

You should have here both servers listed

2) You have configured properly the CCM Group

System -> Cisco CallManager Group -> Click on Find button CCM groups will be listed, click on the one your phones use.

*Usually we only have 1 CCM Group but in case you have more to verify which one are you using look in one phone which Device Pool you have assigned, then System -> Device Pool -> Look for the right one -> Click on it and verify what you have in Cisco CallManager Group parameter.

Click on the proper CCM group and make sure the option Auto-registration Cisco CallManager Group is checked.

Verify both servers are in the Selected Cisco CallManagers Pane.

At this point the configuration for failover should be fine but to make sure we're going to re-create the configuration file for devices. (The one they download via TFTP, since it contains the CCM servers to which they should connect in priority)

To do this:

Service -> Service Parameters

Select your TFTP server (If using both servers as TFTP select anyone) and under service

Cisco TFTP

Click Advanced button and make sure the following parameters are set like this:

Build CNF Files* -> Build All

Enable Caching of Constant and Bin Files at Startup* -> True

Enable Caching of Configuration Files* -> True

Update changes and restart Cisco TFTP service in all servers where it is running.

You will need to reset the phones so they download the latest configuration file.

Once the phone download the latest file you can verify this by checking it on the phone.

Settings -> Network Configuration -> Verify what you have under CallManager 1 and CallManager 2

the SUB need to have the CCM service at least, recommend also as minimum the TFTP and IPVMS.

BTW that is just a cluster, not a intercluster, that term is used for intercluster trunks which allow communication between different clusters.

HTH

javalenc