SS7 Diagnostic byte to Reason Header IW

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.

 

SS7 REL Cause Partial Table from ITU Q.850 Specifications document

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

 

Call Flow Diagram

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.

cf_f6041_sip_ss7_diagnosticiw.png

Call Trace

Click on Call Trace link to view the call trace displaying the Reason Header

 

Configuration

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.

 

Configure SIP Profile and SIP_SS7 Interworking

  1. 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.

  2. 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 SIP Signaling

  1. Right click on the IMG Name physical node object and select New Signaling. The Signaling object is a parent or container object and no configuration is needed here. Refer to the Signaling topic for more information on this object.
  2. Right click on the Signaling object and select New SIP. In the Remote IMG's SIP Profile field, select from the drop down menu the SIP Profile created above. Refer to the SIP Signaling topic for information on configuring the remaining individual fields within this object.

Configure the External Remote Gateway

Configure the information needed to communicate with the remote gateway that will be communicating with the IMG using this feature.

  1. Right click on the Dialogic IMG EMS object and select New External Network Elements. The External Network Elements object is a parent or container object and no configuration is needed here. Refer to the External Network Elements topic for more information on this object.
  2. Right click on the External Network Elements object and select New External Gateways. Again, the External Gateways object is a parent or container object and no configuration is needed here. Refer to the External Gateways topic for more information on this object.
  3. Right click on the External Gateways object and select New External Gateway. Enter a name that identifies this gateway.
  4. Select SIP from the drop down menu in the Gateway Signaling Protocol field and enter an IP address that will be used to communicate with this gateway.
  5. Select from drop down menu of the SIP Profile field, the SIP Profile created above. Refer to the External Gateway topic for more information on configuring the remaining individual fields in this object.

Configure SS7 Channel Group

  1. Right click on the Routing Configuration object and select New Channel Groups. The Channel Groups object is a parent or container object and no configuration is needed here. Refer to the Channel Groups topic for more information on this object.
  2. Right click on the Channel Groups object and select New Channel Group. Enter a name to identify this channel group.
  3. Select SS7 from the drop down menu in the Signaling Type field.
  4. In the Outgoing Translation Table field select the Translation Table created above that has the Screening and/or Presentation Indicator overridden. Refer to the Channel Group topic for more information on configuring the individual fields in this object.
  5. Right click on the Channel Group object and create the ISUP Group. Refer to the ISUP Group topic for more information on configuring this object.
  6. Right click on the ISUP Group object and select New Circuits. Refer to the Circuit Group topic for information on configuring the CICs.

Configure SIP Channel Group

  1. Right click on the Channel Groups object and select New Channel Group. Enter a name to identify this channel group.
  2. Select SIP from the drop down menu in the Signaling Type field. Refer to the Channel Group topic for more information on configuring the individual fields in this object.
  3. Right click on the SIP channel group created and select New IP Network Element. Select from the drop down menu of the IP Network Element field the remote gateway configured above. Refer to the IP Network Element topic for more information on configuring the object.

Configure Routing and Translations

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.

 

Additional Information