SIP 181 Call Is Being Forwarded vs 503 Service Unavailable
SIP 181 (Call Is Being Forwarded) is a 1xx Provisional response, while 503 (Service Unavailable) 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, 503 means that the server is temporarily unable to process the request due to overloading or maintenance. The client should retry after the time indicated in the Retry-After header.
Mô tả
A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
Khi bạn thấy mã này
When the callee has call forwarding enabled and the request is being redirected to another number or device.
Cách khắc phục
No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings.
Mô tả
The server is temporarily unable to process the request due to overloading or maintenance. The client should retry after the time indicated in the Retry-After header.
Khi bạn thấy mã này
During server overload, maintenance windows, or when the server is rate-limiting requests. Common during traffic spikes.
Cách khắc phục
Wait for the time specified in the Retry-After header. If persistent, check server capacity and consider load balancing across multiple SIP proxies.
Sự khác biệt chính
181 is a 1xx Provisional response, while 503 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 503: The server is temporarily unable to process the request due to overloading or maintenance. The client should retry after the time indicated in the Retry-After header.
You encounter 181 when when the callee has call forwarding enabled and the request is being redirected to another number or device.
You encounter 503 when during server overload, maintenance windows, or when the server is rate-limiting requests. Common during traffic spikes.
Khi nào dùng cái nào
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 503 (Service Unavailable): Wait for the time specified in the Retry-After header. If persistent, check server capacity and consider load balancing across multiple SIP proxies.