SIP Redirect Server Support

This feature allows the IMG to respond to the 3XX class of SIP messages returned from a redirect server. 3xx responses provide information about a user's new location, or alternative services that may be able to satisfy the call. This feature is based on RFC 3261 section 8.1.3.4 and RFC 2543.

In a SIP network it is very common to have a re-direct server which determines where to route the call.  The redirect server may reply to the IMG with a 300 response with a list of contacts to try. The IMG will try each one of those contacts one at a time, until the call is completed, to a maximum of 10 attempts. The IMG will only accept redirects to another endpoint in the SIP network. The endpoint does not have to be one of the configured SIP external gateways.

 

This feature is enabled by default in the SIP Profile.

 

Not Supported

 

3XX Response Mapping

If this feature is not enabled, the IMG will map the 3xx responses to 4xx responses, as shown below:

 

Redirection (3xx) Response

Maps to 4xx (client error) response

300 Multiple choices

410 Gone

301 Moved Permanently

410 Gone

302 Moved Temporarily

480 Temporarily Unavailable

305 Use Proxy

410 Gone

380 Alternative Service

410 Gone

any other 3xx response

410 Gone