SIP 199 Early Dialog Terminated vs 503 Service Unavailable
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 503 (Service Unavailable) is a 5xx Server Failure response. 199 indicates that a UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs. 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 UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
Khi bạn thấy mã này
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
Cách khắc phục
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
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
199 is a 1xx Provisional response, while 503 is a 5xx Server Failure response.
SIP 199: A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
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 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
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 199 (Early Dialog Terminated): No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully. 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.