Additional section:
The following table lists the call disconnect code mapping details:
Mapping CPC to SIP cause codes is not permitted for out-of-dialog or relay messages.
(a) Disconnect code 6 and 7 are used by certain ISUP variants with the coding standard of CCITT
(b) Disconnect code 14 (DISCONNECT NUMBER PORTED) is a non-standard code for all Sonus service groups. When GSX software receives this code, the Call Disconnect Reason field of STOP or ATTEMPT Call Data Record (CDR) is set to received code of 14 by ISUP and H.323 service handlers. ISDN service groups set the field to 31 (NORMAL UNSPECIFIED). The SIP signaling service does not recognize this code and sets the field to 500 (SERVER INTERNAL ERROR).
(c) BYE or CANCEL
(d) 403 if the cause location is "network"; 603 if the cause location is "user".
(e) Disconnect code 22 (NUMBER CHANGED) is a Q.850 standard code. When this code is received by the GSX software, the Call Disconnect Reason field of the ATTEMPT CDR is set to receive code 22 by ISUP, ISDN, and H.323 service handlers. The SIP signaling service looks for information in the diagnostic field about a new number where the called party may be reachable. If this information is found, it is added to the Contact header of the SIP response and the Call Disconnect Reason field is set to 301 (MOVED PERMANENTLY); if this information is not present, the field is set to 410 (GONE).
(f) Disconnect codes 23, 24, 45, and 51 are used by ANSI variants with the coding standard NATIONAL.
(g) Disconnect code 30 (RESPONSE TO STATUS ENQUIRY) is a Q.850 standard code. When received by the GSX software, the Call Disconnect Reason field of STOP or ATTEMPT CDR is set to receive code 30 by ISUP and H.323 service handlers. ISDN service groups set the field to 31 (NORMAL UNSPECIFIED). SIP signaling service does not recognize this code, and sets field to 500.
(h) Disconnect code 129 (CHANNEL COLLISION BACKOFF) is a Sonus defined code. When generated at the egress GSX, the code tries to find another circuit/end point on same trunk group. If no circuits are available, call is reattempted on another trunk group. If still no circuits, call is released back to ingress GSX with disconnect code 34 (NO CIRCUIT AVAILABLE). If 129 is generated twice for the same trunk group, the call is released back to the ingress GSX with disconnect reason 135 (COLLISION REATTEMPT EXHAUSTED). The ingress GSX may reattempt the call on another trunk group if a disconnect reason of 34 or 135 is in the Crankback Profile.
When 129 is generated at ingress GSX, code looks for another circuit/end point on same TG. Ifone, call is reattempted on another TG and if still no circuits, call is released with disconnect code 34. If 129 is generated twice for the same TG, call is released with disconnect code 135.
Disconnect code 32 (CALL REJECTED DUE TO FEATURE AT DESTINATION) actually gets sent as cause value 24 when using the coding standard of CCITT for ITU. This value is not supported in the ISDN code, so if it is received the CDR will contain the value 31.
(j) Disconnect code 79 is used for H.323.
(k) Disconnect codes 128, 129, 130, 134, 140, 142, 143, and 148 are mapped to cause value 34 at the ingress side and 47 at the egress side.
(l) Disconnect code 135 is mapped to cause value 31 for EuroISDN and 34 for all other ISDN variants.
(m) Disconnect codes 176 and 177 can be configured to map to any SIP error cause code. By default, they are mapped to SIP cause code 403.
In each of the above cases, the disconnect code that is returned to the preceding switch depends on the type of GSX service handler as well as the type of preceding switch.