SIP 100 Trying vs 199 Early Dialog Terminated
Both SIP 100 (Trying) and 199 (Early Dialog Terminated) belong to the 1xx Provisional category. 100 indicates that the request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses. Meanwhile, 199 means that a UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
विवरण
The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
जब आप इसे देखें
Immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
कैसे ठीक करें
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
विवरण
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
जब आप इसे देखें
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
कैसे ठीक करें
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
मुख्य अंतर
SIP 100: The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
SIP 199: A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
You encounter 100 when immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
कब किसका उपयोग करें
For 100 (Trying): No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration. For 199 (Early Dialog Terminated): No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.