SIP 100 Trying vs 482 Loop Detected
SIP 100 (Trying) is a 1xx Provisional response, while 482 (Loop Detected) 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, 482 means that the server has detected a loop. The request was received with its own address in the Via header, indicating it has been forwarded back to itself.
Beschreibung
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.
Wann Sie es sehen
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.
Wie man es behebt
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
Beschreibung
The server has detected a loop. The request was received with its own address in the Via header, indicating it has been forwarded back to itself.
Wann Sie es sehen
When routing configuration causes a request to cycle between two or more proxies without reaching the callee.
Wie man es behebt
Review proxy routing tables and DNS records. Check for circular references in SIP routing. Fix the routing configuration to break the loop.
Wesentliche Unterschiede
100 is a 1xx Provisional response, while 482 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 482: The server has detected a loop. The request was received with its own address in the Via header, indicating it has been forwarded back to itself.
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 482 when when routing configuration causes a request to cycle between two or more proxies without reaching the callee.
Wann welchen verwenden
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 482 (Loop Detected): Review proxy routing tables and DNS records. Check for circular references in SIP routing. Fix the routing configuration to break the loop.