SIP 199 Early Dialog Terminated vs 486 Busy Here
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 486 (Busy Here) is a 4xx Client Failure response. 199 indicates that a UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs. In contrast, 486 means that the callee's end system was contacted successfully but the callee is currently not willing or able to take additional calls at this end system.
説明
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
このコードが表示される場合
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
解決方法
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
説明
The callee's end system was contacted successfully but the callee is currently not willing or able to take additional calls at this end system.
このコードが表示される場合
When the callee is already on a call and does not have call waiting. The user explicitly rejected the call, or all lines are in use.
解決方法
Wait and try again later. The callee may become available when their current call ends. Consider leaving a voicemail if available.
主な違い
199 is a 1xx Provisional response, while 486 is a 4xx Client Failure response.
SIP 199: A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
SIP 486: The callee's end system was contacted successfully but the callee is currently not willing or able to take additional calls at this end system.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 486 when when the callee is already on a call and does not have call waiting. The user explicitly rejected the call, or all lines are in use.
どちらをいつ使うか
For 199 (Early Dialog Terminated): No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully. For 486 (Busy Here): Wait and try again later. The callee may become available when their current call ends. Consider leaving a voicemail if available.