SIP 180 Ringing vs 488 Not Acceptable Here
SIP 180 (Ringing) is a 1xx Provisional response, while 488 (Not Acceptable Here) 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, 488 means that the request was understood but the session description (SDP) is not acceptable. The response may contain a list of acceptable media parameters.
الوصف
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.
متى تراه
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
كيفية الإصلاح
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.
الوصف
The request was understood but the session description (SDP) is not acceptable. The response may contain a list of acceptable media parameters.
متى تراه
When codec negotiation fails — the callee cannot handle any of the codecs offered in the SDP. Common in interop scenarios.
كيفية الإصلاح
Check the Warning header or SDP in the response for acceptable parameters. Add compatible codecs (e.g., G.711 as a fallback) to your offer.
الفروق الرئيسية
180 is a 1xx Provisional response, while 488 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 488: The request was understood but the session description (SDP) is not acceptable. The response may contain a list of acceptable media parameters.
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 488 when when codec negotiation fails — the callee cannot handle any of the codecs offered in the SDP. Common in interop scenarios.
متى تستخدم أيًا منهما
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 488 (Not Acceptable Here): Check the Warning header or SDP in the response for acceptable parameters. Add compatible codecs (e.g., G.711 as a fallback) to your offer.