SIP 204 No Notification vs 501 Not Implemented
SIP 204 (No Notification) is a 2xx Success response, while 501 (Not Implemented) is a 5xx Server 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, 501 means that the server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
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 does not support the functionality required to fulfill the request. The method is recognized but not implemented.
Quando você o vê
When the SIP method is valid but the server has not implemented it (e.g., INFO, UPDATE, PRACK on a basic server).
Como corrigir
Use a different method that the server supports. Check the Allow header in responses to see supported methods.
Diferenças principais
204 is a 2xx Success response, while 501 is a 5xx Server Failure response.
SIP 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
SIP 501: The server does not support the functionality required to fulfill the request. The method is recognized but not implemented.
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 501 when when the SIP method is valid but the server has not implemented it (e.g., INFO, UPDATE, PRACK on a basic server).
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 501 (Not Implemented): Use a different method that the server supports. Check the Allow header in responses to see supported methods.