SIP 100 Trying vs 204 No Notification
SIP 100 (Trying) is a 1xx Provisional response, while 204 (No Notification) is a 2xx Success response. 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. In contrast, 204 means that the request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
Description
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.
Quand vous le voyez
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.
Comment résoudre
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
Description
The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
Quand vous le voyez
When subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
Comment résoudre
No fix needed. The subscription was accepted but there is no state change to notify about yet.
Différences clés
100 is a 1xx Provisional response, while 204 is a 2xx Success response.
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 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
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 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
Quand utiliser lequel
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 204 (No Notification): No fix needed. The subscription was accepted but there is no state change to notify about yet.