SIP 204 No Notification vs 504 Server Time-out
SIP 204 (No Notification) is a 2xx Success response, while 504 (Server Time-out) 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, 504 means that the server did not receive a timely response from an external server it accessed while attempting to process the request. Different from 408 (client timeout).
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 did not receive a timely response from an external server it accessed while attempting to process the request. Different from 408 (client timeout).
Quando você o vê
When a proxy's request to a downstream server times out. The proxy itself is working, but the next hop is unresponsive.
Como corrigir
Check the downstream server's availability. Verify DNS resolution for the next-hop domain. Consider adjusting transaction timeout values.
Diferenças principais
204 is a 2xx Success response, while 504 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 504: The server did not receive a timely response from an external server it accessed while attempting to process the request. Different from 408 (client timeout).
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 504 when when a proxy's request to a downstream server times out. The proxy itself is working, but the next hop is unresponsive.
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 504 (Server Time-out): Check the downstream server's availability. Verify DNS resolution for the next-hop domain. Consider adjusting transaction timeout values.