SIP 100 Trying vs 416 Unsupported URI Scheme
SIP 100 (Trying) is a 1xx Provisional response, while 416 (Unsupported URI Scheme) 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, 416 means that the server cannot process the request because the URI scheme in the Request-URI is unknown to the server.
विवरण
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.
जब आप इसे देखें
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.
कैसे ठीक करें
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
विवरण
The server cannot process the request because the URI scheme in the Request-URI is unknown to the server.
जब आप इसे देखें
When using a URI scheme (e.g., tel:, im:, pres:) that the receiving server does not support.
कैसे ठीक करें
Use a supported URI scheme. Most SIP servers support sip: and sips: schemes. Check server capabilities with OPTIONS.
मुख्य अंतर
100 is a 1xx Provisional response, while 416 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 416: The server cannot process the request because the URI scheme in the Request-URI is unknown to the server.
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 416 when when using a URI scheme (e.g., tel:, im:, pres:) that the receiving server does not support.
कब किसका उपयोग करें
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 416 (Unsupported URI Scheme): Use a supported URI scheme. Most SIP servers support sip: and sips: schemes. Check server capabilities with OPTIONS.