Sigtran M3UA controlled CICs do not come In Service

Symptom:
After configuring M3UA enabled SS7 signaling, Channel Group, ISUP Group and Circuit Group,  SS7 CICs will not come into service on a Dialogic IMG 1010 Integrated Media Gateway, but are shown as in service on the far-end switch. 

If call tracing is enabled, only outgoing SS7 ISUP messages are displayed; no incoming SS7 messages are displayed in the trace.

Reason for the issue:
In Dialogic Gate Control Element Management System (GCEMS) ClientView, by default, the IMG Sigtran link object is configured with the Network Appearance field set to blank.  With  Network Appearance set to nothing, the IMG does not expect to receive any Network Appearance parameter in the M3UA from the far-end signaling point.   If the far-end sends a Network Appearance parameter, the IMG will reply with an M3UA error code of Invalid network appearance, regardless of the parameter value received.  Further, there will be no indication of the error, in the IMG call trace or the CLI.  

Unlike other signaling types on the IMG, the M3UA signaling cannot be traced from within the CLI, necessitating an Ethernet trace of the IMG interface on which the link is assigned.  The Ethernet trace below illustrates a case where the far-end sends an ISUP GRA inside an M3UA headed that contains a NAP.   The IMG follows with an error.  Only the relevant parts of each packet are shown:

Solution:
Obtain the Network Appearance paramater value used by the far-end, either from an Ethernet trace of the IMG interface on which the Sigtran link is configured, or otherwise.  Then, in ClientView, delete the Sigtran link object and re-add it using the correct Network Appearance value.  The value cannot be changed once the link is configured; it must be assigned at the time the object is committed.  

The following screenshot highlights the field:
 

Workaround:
None, unless the far-end equipment can be modified to not send the NAP.

Product List
Dialogic IMG 1010 Integerated Media Gateway

Glossary of Acronyms / Terms
NAP: Network Appearance Parameter
CIC:  Circuit Identification Code
MTP: Message Transfer Part
GRA: Group Reset Acknowledgement
M3UA: MTP3 User Adaptation Layer