Runt post: A little VG224, MGCP annoyance…

While I am not a fan of MGCP for general gateway setup, I agree that it’s a good protocol to go with when setting up a VG224 device.  For those not familiar, you can use a VG224 device to connect multiple analog devices to your VoIP network.  Keep in mind that each analog device you add to your IP network makes a baby cry, but if you’re going to do it anyway and have quite a few analog stations, these devices make sense.

Up until recently, I had never had the privilege of configuring one of these guys from scratch.  Like adding any MCGP gateway, though, its a pretty straight forward process, so imagine my surprise when my VG224 wouldn’t register with call manager.

I saw the Unregistered status in Call Manager, and I also saw this on the gateway when I did a #show ccm-manager from the CLI. The status stayed in Registering toward the primary, then would occasionally swap to Registering toward the secondary. What had I forgotten?  Most commonly the mistake is to forget to use the fully qualified domain name as the device name in Call Manager. If “ip domain name” is set on the router, be sure to include the domain name as part of your device name when adding your VG224 to CUCM.  (Pro tip: You can see what the FQDN name should be in the #show ccm-manager output.)

This wasn’t my mistake though.  My “mistake” was simply this – I was trying to get the VG224 to register, but I hadn’t added any configuration to the ports.  My thought was “let’s get this thing registered, then I’ll go back in and add the directory numbers to the ports” – the VG224’s thought, however, was “I’m not registering until this chick defines some ports.”

Alas, after about 20 minutes of checking the configuration against known good configurations, I decided to proceed with adding the directory number information to the ports and worry about the registration at the end.  After I configured the first port, though, the VG224 starting showing as Registered in Call Manager and I proceeded to kick myself for wasting my own time.

Here’s what you *should* see in the output of a properly registered VG224 using MGCP, notice the Domain Name, this is what needs to be added in Call Manager for the device name:

My_VG224_#show ccm-manager
MGCP Domain Name: My_VG_224_my.lab.com
Priority        Status                   Host
============================================================
Primary         Registered               10.10.10.1
First Backup    Backup Ready             10.10.10.2
Second Backup   None                     

Current active Call Manager:    10.10.10.1
Backhaul/Redundant link port:   2428
Failover Interval:              30 seconds
Keepalive Interval:             15 seconds
Last keepalive sent:            14:12:27 CDT Apr 25 2002 (elapsed time: 00:00:14)
Last MGCP traffic time:         14:12:27 CDT Apr 25 2002 (elapsed time: 00:00:14)
Last failover time:             15:33:26 CDT Apr 11 2002 from (10.10.10.2)
Last switchback time:           15:35:01 CDT Apr 11 2002 from (10.10.10.1)
Switchback mode:                Graceful
MGCP Fallback mode:             Not Selected
Last MGCP Fallback start time:  None
Last MGCP Fallback end time:    None
MGCP Download Tones:            Disabled
TFTP retry count to shut Ports: 2