The SS7 REL message is very general. The release of a call could be for a number of different reasons. The REL messages on the SIP side such as BYE, and CANCEL try to narrow down the reason a call was released but in some instances does not give enough information. Feature F-6041 interworks the diagnostics field information that is embedded in the REL message on the SS7 side and inputs them into the Reason Header's reason-extension field on the SIP side. The feature is enabled or disabled through a field in the SIP_SS7 Interworking object. Refer to the information below.
ISUP
Cause Value |
Definition | Diagnostics |
1 | Unallocated (unassigned) number | Condition |
2 | No route to specified transit network | Transit network identify |
3 | No route to destination | Condition |
16 | Normal call clearing | Condition |
17 | User busy | CCBS indicator |
21 | Call rejected | Call rejected condition |
22 | Number changed | New destination (DSS 1)/ Called party number (ISUP) |
29 | Facility rejected | Facility identification (DSS 1)/ Parameter name (ISUP) |
34 | No circuit/channel available | CCBS indicator |
43 | Access information discarded | Discarded information element identifier(s) (Note 4) |
49 | Quality of service not available | Condition |
50 | Requested facility not subscribed | Facility identification (DSS 1)/ Parameter name (ISUP) |
57 | Bearer capability not authorized | Attribute identity |
58 | Bearer capability not presently
available |
Attribute identity |
65 | Bearer capability not implemented | Attribute identity |
66 | Channel type not implemented | Channel type |
69 | Requested facility not implemented | Facility identification (DSS 1)/ Parameter name (ISUP) |
82 | Identified channel does not exist | Channel identity |
86 | Call having the requested call
identity
has been cleared |
Clearing cause |
88 | Incompatible destination | Incompatible parameter (DSS 1) |
User-to-user indicators parameter name | ||
96 | Mandatory information element is missing | Information element identifier (Note 4) |
97 | Message type non-existent or not implemented | Message type |
98 | Message not compatible with call state or message type non-existent or not implemented | Message not compatible with call state or message type non-existent or not implemented |
99 | Information element /parameter nonexistent or not implemented | Information element identifier(s) (DSS 1) (Note 4 and Note 5)/ Parameter names |
100 | Invalid information element contents | Information element identifier(s) (Note 4) |
101 | Message not compatible with call state | Message type |
102 | Recovery on timer expiry | Timer number |
103 | Parameter non-existent or not implemented, passed on | Parameter name(s) |
110 | Message with unrecognized parameter, discarded | Parameter name(s), message name |
In the call flow diagram below the call is release on the SS7 side with a cause code of User busy and a diagnostic field value of CCBS. With the feature configured, the diagnostic field is mapped and added to the Reason header's Reason Extension field.
Click on Call Trace link to view the call trace displaying the Reason Header
The procedure below describes the objects that need to be configured for this feature to function. The procedure assumes that all the Basic Configurations such as facilities, network interfaces, profiles, etc have already been configured. Also, since the feature involves SS7, an SS7 stack along with its linkset, links, and routes must be configured before proceeding.
Right click on the Profiles object and select New SIP SGP. Once SIP SGP pane is created, change the SIP Profile ID to something other than '0'. The SIP SGP object with a 0 in the SIP Profile ID field is a default profile and cannot be modified. Once the ID has been modified, the individual fields in the SIP SGP object can be modified. Refer to SIP Profile-10.5.3 topic for more information on configuring the remaining individual fields within this object.
Right click on the SIP Profile just created and select New SIP_SS7 Interworking. In the object that appears, select Enable from the drop down menu in the REL Diagnostic field to Reason-extension field. This will enable the feature in the SIP Profile object. Refer to the SIP_SS7 Interworking topic for more information on configuring the remaining individual fields in this object.
Configure the information needed to communicate with the remote gateway that will be communicating with the IMG using this feature.
At this point, the feature has been configured along with the SIP and SS7 channel groups. The routing and translation configuration can now be achieved so that the calls are between the two channel groups.