1.3 Overview

This document describes the following:

The ILS provides a real-time dynamic directory service (see [Butler] for a historical discussion). This allows online clients who are currently actively connected to the Internet to find other clients and to contact them for collaboration activity such as establishing a peer-to-peer session or joining a multicast conference. Clients who wish to be located when online register with the ILS and provide their name, email address, and some personal information. During registration the connection point (usually an IP address) is associated and stored with the personal details. Other clients can connect to ILS and browse the list of registered clients looking for a specific person. They can then launch their client collaboration application, such as Microsoft NetMeeting, which initiates a real time connection to the selected person.

The Telephony API Internet Locator Service protocol uses LDAP-style (see [LDAP]) requests to store, retrieve, and modify information in the ILS, such as people or conferences. Once a person knows the network presence of another they wish to contact, they can place a call to that person's computer. This call can be live chat, instant messages, shared white boarding, video conferencing, or even just a voice call.

This protocol is used by NetMeeting and TAPI clients to interact with an ILS server.

TAPI is a Component Object Model (COM) interface used for the development of communications applications. When communicating with an ILS server, only the client-side functions in the TAPI interface are used.

ILS is a dynamic directory service that associates people and conferences with the IP addresses of their computers. ILS maintains the correct IP address for people or conferences even when their IP address changes, which is particularly useful when people use Dynamic Host Configuration Protocol (DHCP). To do so, ILS provides an LDAP interface and supports dynamic objects, as specified in [RFC2589].<1>

For a historical overview of this protocol, see [MSDN-InternetLocSrvAPI], [MSDN-MSTelephonyOvw], and [MSDN-WSALookupServiceBegin].