SIP 199 Early Dialog Terminated vs 204 No Notification
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 204 (No Notification) is a 2xx Success 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, 204 means that the request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
Description
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
When You See It
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
How to Fix
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
Description
The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
When You See It
When subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
How to Fix
No fix needed. The subscription was accepted but there is no state change to notify about yet.
Key Differences
199 is a 1xx Provisional response, while 204 is a 2xx Success 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 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
When to Use Which
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 204 (No Notification): No fix needed. The subscription was accepted but there is no state change to notify about yet.