Example 1

A typical example is when the Oracle Communications Session Border Controller performs HNT and non-HNT registration access for endpoints. Possibly the SDP might not be correct, specifically if the device is behind a NAT. Therefore the Oracle Communications Session Border Controller needs to learn the address for which to restrict the media latching, based on the L3 IP address. If the endpoint is not behind a NAT, then the SDP could be used instead if preferred. However, one can make some assumptions that access-type cases will require registration caching, and the cached fixed contact (the public FW address) could be used instead of waiting for any SDP response.