SIP 183 Session Progress vs 487 Request Terminated
SIP 183 (Session Progress) is a 1xx Provisional response, while 487 (Request Terminated) is a 4xx Client Failure response. 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. In contrast, 487 means that the request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
Описание
Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
Когда вы это видите
During call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
Как исправить
No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA.
Описание
The request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
Когда вы это видите
When the caller hangs up before the callee answers (CANCEL sent for pending INVITE). This is normal call abandonment.
Как исправить
No fix needed — the caller intentionally terminated the request. This is normal behavior.
Ключевые различия
183 is a 1xx Provisional response, while 487 is a 4xx Client Failure response.
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 487: The request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
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 487 when when the caller hangs up before the callee answers (CANCEL sent for pending INVITE). This is normal call abandonment.
Когда что использовать
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 487 (Request Terminated): No fix needed — the caller intentionally terminated the request. This is normal behavior.