Method and system for providing directory based services

A method of resolving a session initiation protocol (SIP) destination identifier comprising:

• receiving an initial call-session request from a user-agent application that includes an originating SIP request-uniform request indicator (URI) indicating an originator of the initial call-session request, an ambiguous request URI indicating a party to which the initial call-session request is directed, the ambiguous request-URI being of the form user-name@domain-name and insufficient to fully define a desired request-URI, the initial call-session request further including a SIP header comprising a search term being indicative of additional information relating to the ambiguous request-URI;
• determining possible matches of request-URIs to the ambiguous request-URI using the search term;
• sending an initial response that includes a list of contact addresses corresponding to the possible matches of request-URIs;
• receiving a follow-on request that includes a selection of a given possible match to the ambiguous request-URI, wherein the follow-on request is recognized as a request for sending an additional list of contact addresses corresponding to the possible matches of request-URIs;
• receiving a selection of a given entry from the additional list of contact addresses;
• establishing a call between the requesting user-agent application and a user-agent application corresponding to the selected contact address.