SIP 100 Trying vs 408 Request Timeout
SIP 100 (Trying) is a 1xx Provisional response, while 408 (Request Timeout) is a 4xx Client Failure response. 100 indicates that the request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses. In contrast, 408 means that the server could not produce a response within a suitable time. The client may repeat the request without modifications at any later time.
描述
The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
何时出现
Immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
如何修复
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
描述
The server could not produce a response within a suitable time. The client may repeat the request without modifications at any later time.
何时出现
When the callee does not respond within the configured timeout (e.g., phone rings but is never answered, or the endpoint is unreachable).
如何修复
Check if the callee's device is powered on and registered. Verify network connectivity. Consider adjusting the server's transaction timeout value.
主要区别
100 is a 1xx Provisional response, while 408 is a 4xx Client Failure response.
SIP 100: The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
SIP 408: The server could not produce a response within a suitable time. The client may repeat the request without modifications at any later time.
You encounter 100 when immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
You encounter 408 when when the callee does not respond within the configured timeout (e.g., phone rings but is never answered, or the endpoint is unreachable).
何时使用哪个
For 100 (Trying): No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration. For 408 (Request Timeout): Check if the callee's device is powered on and registered. Verify network connectivity. Consider adjusting the server's transaction timeout value.