SIP 199 Early Dialog Terminated vs 401 Unauthorized
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 401 (Unauthorized) 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, 401 means that the request requires user authentication. The response includes a WWW-Authenticate header with a challenge for the realm.
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 requires user authentication. The response includes a WWW-Authenticate header with a challenge for the realm.
Cuándo lo verás
When making a request that requires Digest authentication. Common for REGISTER and INVITE requests to authenticated SIP trunks.
Cómo solucionarlo
Resend the request with proper Authorization header containing valid credentials (Digest authentication).
Diferencias clave
199 is a 1xx Provisional response, while 401 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 401: The request requires user authentication. The response includes a WWW-Authenticate header with a challenge for the realm.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 401 when when making a request that requires Digest authentication. Common for REGISTER and INVITE requests to authenticated SIP trunks.
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 401 (Unauthorized): Resend the request with proper Authorization header containing valid credentials (Digest authentication).