SIP 181 Call Is Being Forwarded vs 504 Server Time-out
SIP 181 (Call Is Being Forwarded) is a 1xx Provisional response, while 504 (Server Time-out) is a 5xx Server Failure response. 181 indicates that a proxy server may send this to indicate that the call is being forwarded to a different set of destinations. In contrast, 504 means that the server did not receive a timely response from an external server it accessed while attempting to process the request. Different from 408 (client timeout).
説明
A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
このコードが表示される場合
When the callee has call forwarding enabled and the request is being redirected to another number or device.
解決方法
No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings.
説明
The server did not receive a timely response from an external server it accessed while attempting to process the request. Different from 408 (client timeout).
このコードが表示される場合
When a proxy's request to a downstream server times out. The proxy itself is working, but the next hop is unresponsive.
解決方法
Check the downstream server's availability. Verify DNS resolution for the next-hop domain. Consider adjusting transaction timeout values.
主な違い
181 is a 1xx Provisional response, while 504 is a 5xx Server Failure response.
SIP 181: A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
SIP 504: The server did not receive a timely response from an external server it accessed while attempting to process the request. Different from 408 (client timeout).
You encounter 181 when when the callee has call forwarding enabled and the request is being redirected to another number or device.
You encounter 504 when when a proxy's request to a downstream server times out. The proxy itself is working, but the next hop is unresponsive.
どちらをいつ使うか
For 181 (Call Is Being Forwarded): No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings. For 504 (Server Time-out): Check the downstream server's availability. Verify DNS resolution for the next-hop domain. Consider adjusting transaction timeout values.