SIP 204 No Notification vs 603 Decline
SIP 204 (No Notification) is a 2xx Success response, while 603 (Decline) is a 6xx Global 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, 603 means that the callee's machine was contacted successfully but the user explicitly does not wish to or cannot participate. Unlike 600, this may be because the callee doesn't want to communicate, not necessarily
Description
The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
When You See It
When subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
How to Fix
No fix needed. The subscription was accepted but there is no state change to notify about yet.
Description
The callee's machine was contacted successfully but the user explicitly does not wish to or cannot participate. Unlike 600, this may be because the callee doesn't want to communicate, not necessarily because they're busy.
When You See It
When the callee explicitly declines the call. This is an active rejection, not a busy or unavailable state.
How to Fix
The callee has declined. Respect their decision. Consider alternative communication methods (email, messaging).
Key Differences
204 is a 2xx Success response, while 603 is a 6xx Global Failure response.
SIP 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
SIP 603: The callee's machine was contacted successfully but the user explicitly does not wish to or cannot participate. Unlike 600, this may be because the callee doesn't want to communicate, not necessarily
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 603 when when the callee explicitly declines the call. This is an active rejection, not a busy or unavailable state.
When to Use Which
For 204 (No Notification): No fix needed. The subscription was accepted but there is no state change to notify about yet. For 603 (Decline): The callee has declined. Respect their decision. Consider alternative communication methods (email, messaging).