IMG 1010 - Supported 3xx Redirect Responses

3xx responses give information about the user's new location, or about alternative services that might be able to satisfy the call. 

3xx Redirect Support is enabled by default on the IMG and is configurable with the SIP Profile (SGP) on a per gateway basis - see IMG 1010 - SIP Profile - 10.5.3 and IMG 1010 - SIP Redirect Server Support

300 Multiple Choices

The address in the request resolved to several choices, each with its own specific location, and the user (or UA) can select a preferred communication end point and redirect its request to that location.

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