VG224 ringback issue

Hey Guys,

Recently my customer reported ringback issue on their VG224 analog gateway. Basically, when someone tried to call analog phones via VG224, they just heard couple ringback tones and nothing after. On the called party side though, phones were not ringing at all.

Call flow:

PhoneACUCMVG224Analog Phone AN1E4A542E68400 (stcapp controlled port on the gateway)

What should happen is once CUCM gets call request from PhoneA, it should inform VG224 that there’s a call on its SCCP controlled port AN1E4A542E68400 to which analog phone is plugged in. Then VG224 translates all SCCP signals to analog signals and we’re good.

So, at the first glance issue sounds like some call processing thing. I took ccm traces, searched for endpoint name “AN1E4A542E68400” and found tons of following messages:

38969182.000 |13:43:42.954 |Created  |                                       |                               |StationD(12,100,64,3214012)      |StationInit(12,100,63,1)         |                                         |NumOfCurrentInstances: 55
38969183.000 |13:43:42.954 |SdlSig   |StationRegister                        |wait_register                  |StationD(12,100,64,3214012)      |StationInit(12,100,63,1)         |12,100,63,1.3237104^*^*                  |[R:V-H:0,N:0,L:0,V:0,Z:0,D:0] Name=AN1E4A542E68400 Type=30027 maxStreams=1 activeStreams=0 protocolVer=2010015 stationIpAddr=0x{a,f6,88,b} stationIpV6Addr=0x{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
38969183.001 |13:43:42.955 |AppInfo  |Device=AN1E4A542E68400 in DB already but cannot register. isDeviceNameAllowedToRegister=CallManager Pkid(59736a89-0df9-4252-8ad3-b6e0cb1229ca) is not a member of Call Manager Group(CM Group 1) (isCallManagerMemberOfDevicePool)
38969183.002 |13:43:42.955 |AppInfo  |CcmdbStationRegistrationProfileBuilder::getBasicRegistrationProfile::init() - failed rc(2)
38969183.003 |13:43:42.955 |AppInfo  |StationD:    (3214012) Error, ccmdbGetStationRegistrationProfile (not configured)
38969183.004 |13:43:42.955 |AppInfo  |DeviceTransientConnection - A device attempted to register but did not complete registration Connecting Port:2000 Device Name:AN1E4A542E68400 Device IP Address:10.246.136.11 Device type:30027 Reason Code:3 Protocol:SCCP IPAddressAttributes:2 UNKNOWN_PARAMNAME:LastSignalReceived:StationRegister UNKNOWN_PARAMNAME:StationState:wait_register App ID:Cisco CallManager Cluster ID:CUCM Cluster A Node ID:SUB2
38969183.005 |13:43:42.955 |AlarmErr |AlarmClass: CallManager, AlarmName: DeviceTransientConnection, AlarmSeverity: Error, AlarmMessage: , AlarmDescription: A device attempted to register but did not complete registration, AlarmParameters:  ConnectingPort:2000, DeviceName:AN1E4A542E68400, IPAddress:10.246.136.11, DeviceType:30027, Reason:3, Protocol:SCCP, IPAddrAttributes:2, UNKNOWN_PARAMNAME:LastSignalReceived:StationRegister, UNKNOWN_PARAMNAME:StationState:wait_register, AppID:Cisco CallManager, ClusterID:CUCM Cluster A, NodeID:SUB2,

Let’s focus on following line:

|AlarmErr |AlarmClass: CallManager, AlarmName: DeviceTransientConnection, AlarmSeverity: Error, AlarmMessage: , AlarmDescription: A device attempted to register but did not complete registration, AlarmParameters: ConnectingPort:2000, DeviceName:AN1E4A542E68400, IPAddress:10.246.136.11, DeviceType:30027, Reason:3, Protocol:SCCP, IPAddrAttributes:2, UNKNOWN_PARAMNAME:LastSignalReceived:StationRegister, UNKNOWN_PARAMNAME:StationState:wait_register, AppID:Cisco CallManager, ClusterID:CUCM Cluster A, NodeID:SUB2,

What is the Transient Connection? Here’s official Cisco explanation for that error message:

“A connection was established and immediately dropped before completing registration. Incomplete registration may indicate that a device is rehoming in the middle of registration. The alarm could also indicate a device misconfiguration, database error, or an illegal/unknown device trying to attempt a connection. Network connectivity problems can affect device registration, or the restoration of a primary Unified CM may interrupt registration”

Basically, for some reason our device is continuously trying to register and fails all the time. When I checked CM Group of that device, I found that first Call Manager processing node is SUB1, and second one is SUB2, but in the trace we can see that NodeID which reported problem and receives registration attempts is actually SUB2 (highlighted above in red).

OK, let’s go to VG224 configuration then.

sccp local FastEthernet0/0
sccp ccm 22.22.22.22 identifier 20 version 7.0 // this is our SUB2
sccp ccm 11.11.11.11 identifier 10 version 7.0 // this is our SUB1
sccp
!
sccp ccm group 1
 associate ccm 20 priority 1
 associate ccm 10 priority 2

Take a closer look here… VG224 configuration basically says: Primary Call Manager for registration is SUB2, and secondary Call Manager for registration is SUB1. But wait a second… Wasn’t our CM Group configured opposite?

Bingo.

What happened was following:

  1. From VG224 perspective, SCCP controlled ports were supposed to register to SUB2
  2. From CUCM perspective, as per CM Group configuration, SCCP ports were supposed to register to SUB1
  3. That caused internal security error, since Call Manager has received registration on different call processing node than it thought it would.

!NOTE! This is exactly same as with casual phones. Sometimes, when you change phone’s Device Pool/CM Group, but phone for any reason will not get the updated configuration file, it will try register to different subscriber than Call Manager is aware of. Phone will then stuck in Registration Rejected state until you revert change or push updated config file.

Basically, config had to be changed somewhere. What I did was to change VG224 config in following way:

sccp ccm group 1
no associate ccm 20 priority 1
no associate ccm 10 priority 2

associate ccm 10 priority 1
associate ccm 20 priority 2

Now SUB1 has first priority on both VG224 and CM Group.

SCCP ports started registering and taking calls properly.

 

Take care!

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