Incomplete Call Behavior

Owned by Kelli Higdon
Last updated: Apr 02, 2024
4 min read

 

 

Below are some common scenarios when an incomplete call arises.

No Answer from User (SS7 to H.323)

  • When the B-side of the call does not respond to the IMG 2020 and the T310 timer expires (3 Minutes)

  • Q.931 cause code 0x66 (Recovery from Timer expiry) or Cancel in case of SIP will be sent to the B-side of the call. Q.931 Cause code 0x13 (No answer from user) or 480 Temporarily Unavailable in case of SIP will be sent to the A-side of the call.

  • The cause codes logged in the RADIUS records will be set to 0x66 and 0x13 for the B-side and A-side respectively

  • The RTP IP address of the B-side (In case of egress H.323) will be logged depending on whether the B-side has sent the OLC back to the IMG 2020 or not.

  • The RTP IP address of the B-side (In case of egress SIP) will be logged as ‘0.0.0.0’ since the IMG 2020 did not receive the 200 OK.  

No Circuit/Channel Available (SS7 to H.323)

  • When all channels are busy or OOS for the B-side of the call

  • Q.931 cause code 0x22 (No circuit/channel available) or 503 Service Unavailable in case of SIP will be sent to the A-side of the call

  • The cause codes logged in the RADIUS records will be set to 0x22 for both sides of the call

  • The RTP and Signaling IP addresses of the B-side (In case of egress SIP or H.323) will be logged as 0.0.0.0 since the outgoing call is not attempted (no signaling messages have been sent)

Unallocated Number (SS7 to H.323)


 

  • If the remote side responds to the IMG 2020 with cause code 0x01, cause code 0x01 will be propagated to the A-side of the call.

  • The cause codes logged in the RADIUS records will be set to 0x01 for both sides of the call.

  • The RTP IP addresses of the B-side (In case of egress SIP or H.323) will be logged as 0.0.0.0 since the outgoing call is not attempted at all.     

  • When matching of the incoming translation table fails, Q.931 cause code 0x01 (Unallocated Number) or 404 Not Found will be sent to the A-side of the call. There is no RADIUS record for the B-side of the call in this case.  

H.323 Release Reason (SS7 to H.323)

  • When receiving an early release for an egress H.323 call with an H.225 Reason IE instead of a Q.931 cause code IE.

  • The Q.931 mapped value of the received H.225 Reason (Based on H.225.0 specification) will be sent to the A-side of the call.

  • The cause codes logged in the RADIUS records will be set to the Q.931 mapped value for both sides of the call.  

User Busy

  • Q.931 cause code 0x11 (User Busy) will be received from the B-side of the call or 486 Busy Here in case of SIP, which will result into cause code 0x11 or 486 Busy Here being propagated to the A-side of the call.

  • The cause codes logged in the RADIUS records will be set to 0x11 for both sides of the call.

  • The RTP IP address of the B-side (In case of egress SIP or H.323) will be logged as 0.0.0.0 since the call was not answered and the IMG 2020 is unaware of the RTP stream destination IP address.   

NON-Fast Start

  • In case of ingress Non-Fast-Start H.323 calls, the Remote side IP address will not be logged in the Accounting start for the A-side. This is because in case of Non-Fast-Start H.323 call, the Fast Start logical channels element is not included in the Setup message received from the A-side

  • The remote H.323 address will always be logged to the Accounting Stop of the B-side 

 

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