SIP 100 Trying vs 430 Flow Failed
SIP 100 (Trying) is a 1xx Provisional response, while 430 (Flow Failed) 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, 430 means that the specific flow to a user agent has failed but other flows may succeed. Used with SIP outbound (RFC 5626).
Description
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.
Quand vous le voyez
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.
Comment résoudre
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
Description
The specific flow to a user agent has failed but other flows may succeed. Used with SIP outbound (RFC 5626).
Quand vous le voyez
When using SIP outbound connections and the specific TCP/TLS connection (flow) to the UA has been lost.
Comment résoudre
The proxy should attempt delivery via other registered flows. The UA should re-register to establish a new flow.
Différences clés
100 is a 1xx Provisional response, while 430 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 430: The specific flow to a user agent has failed but other flows may succeed. Used with SIP outbound (RFC 5626).
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 430 when when using SIP outbound connections and the specific TCP/TLS connection (flow) to the UA has been lost.
Quand utiliser lequel
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 430 (Flow Failed): The proxy should attempt delivery via other registered flows. The UA should re-register to establish a new flow.