SIP 199 Early Dialog Terminated vs 400 Bad Request
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 400 (Bad Request) 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, 400 means that the request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
Descripción
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
Cuándo lo verás
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
Cómo solucionarlo
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
Descripción
The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
Cuándo lo verás
When the SIP message has syntax errors, missing required headers, or invalid header values.
Cómo solucionarlo
Review the SIP message for syntax errors. Check required headers (To, From, Call-ID, CSeq, Via, Max-Forwards) and ensure proper formatting.
Diferencias clave
199 is a 1xx Provisional response, while 400 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 400: The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 400 when when the SIP message has syntax errors, missing required headers, or invalid header values.
Cuándo usar cada uno
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 400 (Bad Request): Review the SIP message for syntax errors. Check required headers (To, From, Call-ID, CSeq, Via, Max-Forwards) and ensure proper formatting.