SIP 183 Session Progress vs 607 Unwanted
SIP 183 (Session Progress) is a 1xx Provisional response, while 607 (Unwanted) is a 6xx Global 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, 607 means that the called party did not want this call from the calling party. This response is used for robocall and spam call blocking.
Descrição
Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
Quando você o vê
During call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
Como corrigir
No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA.
Descrição
The called party did not want this call from the calling party. This response is used for robocall and spam call blocking.
Quando você o vê
When the callee's system identifies the call as spam or unwanted. Used in STIR/SHAKEN call verification frameworks.
Como corrigir
If you are a legitimate caller being blocked as spam, ensure your STIR/SHAKEN attestation level is 'A' (full attestation). Contact the callee through alternative means.
Diferenças principais
183 is a 1xx Provisional response, while 607 is a 6xx Global 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 607: The called party did not want this call from the calling party. This response is used for robocall and spam call blocking.
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 607 when when the callee's system identifies the call as spam or unwanted. Used in STIR/SHAKEN call verification frameworks.
Quando usar qual
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 607 (Unwanted): If you are a legitimate caller being blocked as spam, ensure your STIR/SHAKEN attestation level is 'A' (full attestation). Contact the callee through alternative means.