SIP 199 Early Dialog Terminated vs 481 Call/Transaction Does Not Exist
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 481 (Call/Transaction Does Not Exist) 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, 481 means that the UAS received a request that does not match any existing dialog or transaction. The call state may have been lost.
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 UAS received a request that does not match any existing dialog or transaction. The call state may have been lost.
Cuándo lo verás
When sending a BYE, re-INVITE, or UPDATE for a call that the server has no record of. Common after server restarts.
Cómo solucionarlo
The dialog has been lost. Terminate the local call state. For re-INVITE failures, re-establish the call from scratch.
Diferencias clave
199 is a 1xx Provisional response, while 481 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 481: The UAS received a request that does not match any existing dialog or transaction. The call state may have been lost.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 481 when when sending a BYE, re-INVITE, or UPDATE for a call that the server has no record of. Common after server restarts.
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 481 (Call/Transaction Does Not Exist): The dialog has been lost. Terminate the local call state. For re-INVITE failures, re-establish the call from scratch.