ABSTRACT
We describe the user identity and the Network-Asserted Identity (NAI) that can be used over the Session Initiation Protocol (SIP) network. A SIP user may have multiple identities to be used for many purposes, and some of the user identities may be public while others can be private identities. All of these user identities can be shared with other SIP users for communications as appropriate. Although user identities can be both public and private, a NAI is considered always applicable over the private SIP network. The details of both user identity and NAI are provided here.
