SIP 183 Session Progress vs 199 Early Dialog Terminated
Both SIP 183 (Session Progress) and 199 (Early Dialog Terminated) belong to the 1xx Provisional category. 183 indicates that used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP. Meanwhile, 199 means that a UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
Mô tả
Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
Khi bạn thấy mã này
During call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
Cách khắc phục
No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA.
Mô tả
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
Khi bạn thấy mã này
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
Cách khắc phục
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
Sự khác biệt chính
SIP 183: Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
SIP 199: A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
You encounter 183 when during call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
Khi nào dùng cái nào
For 183 (Session Progress): No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA. For 199 (Early Dialog Terminated): No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.