SIP 204 No Notification vs 482 Loop Detected
SIP 204 (No Notification) is a 2xx Success response, while 482 (Loop Detected) is a 4xx Client Failure response. 204 indicates that the request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request. 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.
Descrição
The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
Quando você o vê
When subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
Como corrigir
No fix needed. The subscription was accepted but there is no state change to notify about yet.
Descrição
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.
Quando você o vê
When routing configuration causes a request to cycle between two or more proxies without reaching the callee.
Como corrigir
Review proxy routing tables and DNS records. Check for circular references in SIP routing. Fix the routing configuration to break the loop.
Diferenças principais
204 is a 2xx Success response, while 482 is a 4xx Client Failure response.
SIP 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
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 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 482 when when routing configuration causes a request to cycle between two or more proxies without reaching the callee.
Quando usar qual
For 204 (No Notification): No fix needed. The subscription was accepted but there is no state change to notify about yet. 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.