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)