HP MSR SERIES Configuration Manual page 649

Figure 657 Call setup procedures involving a proxy server
This is a simplified scenario where only one proxy server is involved and no registrar is present. However,
a complex scenario can involve multiple proxy servers and registrars.
Call redirection
When a SIP redirect server receives a session request, it sends back a response indicating the address of
the called SIP endpoint instead of forwarding the request. The calling and called endpoints therefore can
send request and response to each other directly. See Figure 658.
632