SIP 300 Multiple Choices vs 305 Use Proxy
Both SIP 300 (Multiple Choices) and 305 (Use Proxy) belong to the 3xx Redirection category. 300 indicates that the address in the request resolved to several choices, each with its own location. The user or UA can select a preferred communication endpoint. Meanwhile, 305 means that the requested resource must be accessed through the proxy given by the Contact header field.
Description
The address in the request resolved to several choices, each with its own location. The user or UA can select a preferred communication endpoint.
When You See It
When a user has multiple registered devices or contact addresses and the server cannot determine which one to use.
How to Fix
Select one of the provided Contact addresses and resend the request to that specific URI.
Description
The requested resource must be accessed through the proxy given by the Contact header field.
When You See It
When the request must be routed through a specific outbound proxy server.
How to Fix
Resend the request through the proxy specified in the Contact header of this response.
Key Differences
SIP 300: The address in the request resolved to several choices, each with its own location. The user or UA can select a preferred communication endpoint.
SIP 305: The requested resource must be accessed through the proxy given by the Contact header field.
You encounter 300 when when a user has multiple registered devices or contact addresses and the server cannot determine which one to use.
You encounter 305 when when the request must be routed through a specific outbound proxy server.
When to Use Which
For 300 (Multiple Choices): Select one of the provided Contact addresses and resend the request to that specific URI. For 305 (Use Proxy): Resend the request through the proxy specified in the Contact header of this response.