SIP 301 Moved Permanently vs 422 Session Interval Too Small
SIP 301 (Moved Permanently) is a 3xx Redirection response, while 422 (Session Interval Too Small) is a 4xx Client Failure response. 301 indicates 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. In contrast, 422 means that the request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
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.
Description
The request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
When You See It
When using SIP session timers (RFC 4028) and the proposed session refresh interval is below the server's minimum.
How to Fix
Increase the Session-Expires value to at least the value indicated in the Min-SE header of the 422 response.
Key Differences
301 is a 3xx Redirection response, while 422 is a 4xx Client Failure response.
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.
SIP 422: The request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
You encounter 301 when when a user has permanently changed their SIP address. All future calls should be directed to the new URI.
You encounter 422 when when using SIP session timers (RFC 4028) and the proposed session refresh interval is below the server's minimum.
When to Use Which
For 301 (Moved Permanently): Update your address book or routing tables to use the new Contact URI provided in the response. For 422 (Session Interval Too Small): Increase the Session-Expires value to at least the value indicated in the Min-SE header of the 422 response.