SIP 180 Ringing vs 423 Interval Too Brief
SIP 180 (Ringing) is a 1xx Provisional response, while 423 (Interval Too Brief) is a 4xx Client Failure response. 180 indicates that the UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end. 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
The UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
Quand vous le voyez
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
Comment résoudre
No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings.
Description
The expiration time in the request is too short. The response contains a Min-Expires header indicating the minimum allowed value.
Quand vous le voyez
When a REGISTER or SUBSCRIBE request has an Expires value that is below the server's minimum. Common with aggressive keep-alive timers.
Comment résoudre
Increase the Expires header value to at least the Min-Expires value from the response.
Différences clés
180 is a 1xx Provisional response, while 423 is a 4xx Client Failure response.
SIP 180: The UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
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 180 when during call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
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.
Quand utiliser lequel
For 180 (Ringing): No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings. For 423 (Interval Too Brief): Increase the Expires header value to at least the Min-Expires value from the response.