SIP 204 No Notification vs 489 Bad Event
SIP 204 (No Notification) is a 2xx Success response, while 489 (Bad Event) 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, 489 means that the server did not understand the event package specified in the Event header of a SUBSCRIBE request.
描述
The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
何时出现
When subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
如何修复
No fix needed. The subscription was accepted but there is no state change to notify about yet.
描述
The server did not understand the event package specified in the Event header of a SUBSCRIBE request.
何时出现
When subscribing to an event package that the server does not support (e.g., dialog, presence, message-summary).
如何修复
Check which event packages the server supports (OPTIONS request) and use a supported event package name.
主要区别
204 is a 2xx Success response, while 489 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 489: The server did not understand the event package specified in the Event header of a SUBSCRIBE request.
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 489 when when subscribing to an event package that the server does not support (e.g., dialog, presence, message-summary).
何时使用哪个
For 204 (No Notification): No fix needed. The subscription was accepted but there is no state change to notify about yet. For 489 (Bad Event): Check which event packages the server supports (OPTIONS request) and use a supported event package name.