SIP 180 Ringing vs 501 Not Implemented
SIP 180 (Ringing) is a 1xx Provisional response, while 501 (Not Implemented) is a 5xx Server 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, 501 means that the server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
説明
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.
このコードが表示される場合
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
解決方法
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.
説明
The server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
このコードが表示される場合
When the SIP method is valid but the server has not implemented it (e.g., INFO, UPDATE, PRACK on a basic server).
解決方法
Use a different method that the server supports. Check the Allow header in responses to see supported methods.
主な違い
180 is a 1xx Provisional response, while 501 is a 5xx Server 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 501: The server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
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 501 when when the SIP method is valid but the server has not implemented it (e.g., INFO, UPDATE, PRACK on a basic server).
どちらをいつ使うか
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 501 (Not Implemented): Use a different method that the server supports. Check the Allow header in responses to see supported methods.