SIP 301 Moved Permanently vs 380 Alternative Service
Both SIP 301 (Moved Permanently) and 380 (Alternative Service) belong to the 3xx Redirection category. 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. Meanwhile, 380 means that the call was not successful but alternative services are possible. The response body contains a description of alternative services.
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 call was not successful but alternative services are possible. The response body contains a description of alternative services.
When You See It
Rarely seen in practice. Indicates that the request cannot be fulfilled as-is but the user may be reached via an alternative method.
How to Fix
Check the response body for alternative service descriptions and attempt to reach the user through those channels.
Key Differences
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 380: The call was not successful but alternative services are possible. The response body contains a description of alternative services.
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 380 when rarely seen in practice. Indicates that the request cannot be fulfilled as-is but the user may be reached via an alternative method.
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 380 (Alternative Service): Check the response body for alternative service descriptions and attempt to reach the user through those channels.