SIP 204 No Notification vs 301 Moved Permanently
SIP 204 (No Notification) is a 2xx Success response, while 301 (Moved Permanently) is a 3xx Redirection response. 204 indicates that the request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request. In contrast, 301 means that the user can no longer be found at the address in the Request-URI. The client should direct future requests to the new address in the Contact header.
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 user can no longer be found at the address in the Request-URI. The client should direct future requests to the new address in the Contact header.
When You See It
When a user has permanently changed their SIP address. All future calls should be directed to the new URI.
How to Fix
Update your address book or routing tables to use the new Contact URI provided in the response.
Key Differences
204 is a 2xx Success response, while 301 is a 3xx Redirection response.
SIP 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
SIP 301: The user can no longer be found at the address in the Request-URI. The client should direct future requests to the new address in the Contact header.
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 301 when when a user has permanently changed their SIP address. All future calls should be directed to the new URI.
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 301 (Moved Permanently): Update your address book or routing tables to use the new Contact URI provided in the response.