SIP 199 Early Dialog Terminated vs 501 Not Implemented
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 501 (Not Implemented) is a 5xx Server 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, 501 means that the server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
描述
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
何时出现
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
如何修复
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
描述
The server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
何时出现
When the SIP method is valid but the server has not implemented it (e.g., INFO, UPDATE, PRACK on a basic server).
如何修复
Use a different method that the server supports. Check the Allow header in responses to see supported methods.
主要区别
199 is a 1xx Provisional response, while 501 is a 5xx Server 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 501: The server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 501 when when the SIP method is valid but the server has not implemented it (e.g., INFO, UPDATE, PRACK on a basic server).
何时使用哪个
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 501 (Not Implemented): Use a different method that the server supports. Check the Allow header in responses to see supported methods.