SIP 180 Ringing vs 422 Session Interval Too Small
SIP 180 (Ringing) is a 1xx Provisional response, while 422 (Session Interval Too Small) 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, 422 means that the request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
설명
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.
이 코드를 보게 되는 경우
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
해결 방법
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.
설명
The request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
이 코드를 보게 되는 경우
When using SIP session timers (RFC 4028) and the proposed session refresh interval is below the server's minimum.
해결 방법
Increase the Session-Expires value to at least the value indicated in the Min-SE header of the 422 response.
주요 차이점
180 is a 1xx Provisional response, while 422 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 422: The request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
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 422 when when using SIP session timers (RFC 4028) and the proposed session refresh interval is below the server's minimum.
언제 어떤 것을 사용할지
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 422 (Session Interval Too Small): Increase the Session-Expires value to at least the value indicated in the Min-SE header of the 422 response.