SIP 180 Ringing vs 606 Not Acceptable
SIP 180 (Ringing) is a 1xx Provisional response, while 606 (Not Acceptable) is a 6xx Global 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, 606 means that the user's agent was contacted successfully but some aspects of the session description (SDP) are not acceptable. Unlike 488, this is a global failure — no other server can satisfy this request.
描述
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.
何时出现
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
如何修复
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.
描述
The user's agent was contacted successfully but some aspects of the session description (SDP) are not acceptable. Unlike 488, this is a global failure — no other server can satisfy this request.
何时出现
When the callee definitively cannot accept any of the offered media types or codecs. Different from 488 which is location-specific.
如何修复
Check the Warning header or response body for which session parameters are unacceptable. Modify the SDP offer to use compatible codecs and media types.
主要区别
180 is a 1xx Provisional response, while 606 is a 6xx Global 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 606: The user's agent was contacted successfully but some aspects of the session description (SDP) are not acceptable. Unlike 488, this is a global failure — no other server can satisfy this request.
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 606 when when the callee definitively cannot accept any of the offered media types or codecs. Different from 488 which is location-specific.
何时使用哪个
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 606 (Not Acceptable): Check the Warning header or response body for which session parameters are unacceptable. Modify the SDP offer to use compatible codecs and media types.