SIP 199 Early Dialog Terminated vs 423 Interval Too Brief
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 423 (Interval Too Brief) 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, 423 means that the expiration time in the request is too short. The response contains a Min-Expires header indicating the minimum allowed value.
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 expiration time in the request is too short. The response contains a Min-Expires header indicating the minimum allowed value.
When You See It
When a REGISTER or SUBSCRIBE request has an Expires value that is below the server's minimum. Common with aggressive keep-alive timers.
How to Fix
Increase the Expires header value to at least the Min-Expires value from the response.
Key Differences
199 is a 1xx Provisional response, while 423 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 423: The expiration time in the request is too short. The response contains a Min-Expires header indicating the minimum allowed value.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 423 when when a REGISTER or SUBSCRIBE request has an Expires value that is below the server's minimum. Common with aggressive keep-alive timers.
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 423 (Interval Too Brief): Increase the Expires header value to at least the Min-Expires value from the response.