NETWORK_INFO

Obscure any originating IP address information, contact URIs, and anonymize all traffic involved with sending/receiving any media streams or call content.

Examples of this include the "headers" portions of RFC 3323 as well as the History-Info (described in RFC 4244) for a SIP CM. This SHOULD have the effect of hiding address information from the remote contact (ie, the contact cannot know what IP address the session is originated from). Obviously the network still needs to be able to route information between contacts, so this provides no guarantees of what can be seen by intermediaries.