SIP 183 Session Progress vs 430 Flow Failed
SIP 183 (Session Progress) is a 1xx Provisional response, while 430 (Flow Failed) 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, 430 means that the specific flow to a user agent has failed but other flows may succeed. Used with SIP outbound (RFC 5626).
説明
Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
このコードが表示される場合
During call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
解決方法
No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA.
説明
The specific flow to a user agent has failed but other flows may succeed. Used with SIP outbound (RFC 5626).
このコードが表示される場合
When using SIP outbound connections and the specific TCP/TLS connection (flow) to the UA has been lost.
解決方法
The proxy should attempt delivery via other registered flows. The UA should re-register to establish a new flow.
主な違い
183 is a 1xx Provisional response, while 430 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 430: The specific flow to a user agent has failed but other flows may succeed. Used with SIP outbound (RFC 5626).
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 430 when when using SIP outbound connections and the specific TCP/TLS connection (flow) to the UA has been lost.
どちらをいつ使うか
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 430 (Flow Failed): The proxy should attempt delivery via other registered flows. The UA should re-register to establish a new flow.