Presence-based, real-time, multimedia communication like this hasn't arrived at the enterprise yet, but it's not that far off either.You're in a conference room in New York and you need to get in touch with Bob in Los Angeles. You don't know if Bob is in his office, on the road or in a meeting, so you don't know the best way to reach him.But what if you could launch your Windows Messenger instant message application, click on Bob's name in your buddy list and immediately discover Bob's "presence." He happens to be in his office and can be reached over instant message or phone.You decide to call Bob, so you click the voice-call option on your screen and start a conversation via softphone. As you're talking, Bob suggests that you add Sue to the call, so you check for her presence and see that she's available over voice and videoconference.With a few more mouse clicks, you create a three-way conversation; you and Sue sharing a videoconference, with Bob hooked in over his voice link.Of course, presence-based, real-time, multimedia communication like this hasn't arrived at the enterprise yet, but it's not that far off either.One key driver is that\u00a0Microsoft\u00a0has bundled its Messenger client into Windows XP. And the latest version of Messenger supports Session Initiation Protocol (SIP), an Internet Engineering Task Force (IETF) standard for interactive communication sessions between users. Working with Windows Messenger and SIP That means as XP is rolled out across enterprise desktops, end users will have a built-in, standards-based client capable of talking to other SIP-based devices, be they phones, gateways, servers or PBXs.But simply having Windows Messenger clients is only half the equation. That will give you basic, point to point, voice or video communication between two people on an enterprise network.If you want the full breadth of features, such as multiparty conferencing, clicking on a name in your buddy list to place a call, dragging and dropping names from an Outlook folder to an icon on your desktop and starting a telephone call, then an application server or a SIP-savvy IP PBX is needed.If you can wait, Microsoft recently announced that it will be moving instant messaging features from its Exchange e-mail server to a new server, code-named Greenwich, which will be part of the .Net server family. Estimated ship date is June 2003.In addition vendors with very different backgrounds are offering or have announced products that piggyback on the Messenger client, with more expected to jump on the bandwagon in the next year.\u2022 From the voice side, eDial, a Waltham, Mass., company that specializes in audioconferencing, is shipping an appliance that converts SIP to other common IP protocols as well as legacy telephony protocols, and provides interfaces to existing services.With an eDial Communication Server, users can do online directory dialing from Outlook using the Windows Messenger SIP stack, click on a link in a Web customer support page to speak with a person, and create an instant, multiparty, multiprotocol audioconference.\u2022 Israeli videoconferencing vendor VCON has added a SIP proxy to its MXM 3.0 application server and gatekeeper for H.323 rich media conferencing.Bandwidth requirement The general rule of thumb is that for a fully interactive, business-like meeting each user must have a stable (never less than) 200K bit\/sec connection with never more than 400 ms of latency end to end.Anyone running Messenger who is registered with an MXM server can establish SIP-to-SIP calls through the MXM directory interface, receive a video call from a SIP video-enabled client (another Windows Messenger user) on the corporate network, forward a call to another party registered on the MXM server and benefit from MXM's other centralized management and video PBX services. "We don't believe companies should have to wait to choose between one protocol or the other at this point in time," says Gordon Daugherty, president of VCON, Inc. "With the MXM's SIP support, the IT manager can establish each SIP client's maximum and minimum bandwidth allocation, assign permissions, such as use of gateway or conferencing resources, monitor call status, and, if needed, establish calls between two or more SIP parties remotely."The MXM administrator also can use the server to review Call Detail Records of SIP as well as H.323 clients on all completed calls. The MXM license fee runs $100 to $300 per user.\u2022 On the IP PBX side, Sphere Communications expects to release enhancements to its Sphericall server next year that offer Messenger users a highly converged yet flexible phone-PC experience.The Sphericall IP PBX will treat any Messenger client as any other IP phone on the network. Once registered with MSN Messenger and the Sphericall services, a new menu appears on the Messenger interface.Users will be able to use their mouse to transfer a call from their Messenger interface to a telephone or to a SIP user on their buddy list.A call also can be transferred by entering a third party's phone number into a dialog box. Since presence is integral to the instant-messenge interface, users will know if the other party is available.A Messenger user can choose to place a call with any device (IP phone or an IP call through a gateway) or to bring in another person from the directory or buddy list. Also, if a Messenger user receives a call from another Sphericall registered IP phone, a box pops up on the PC telling him who is calling on his desk phone.Users also can specify what the server should do (call forward to attendant or call forward to the messaging system) if a Messenger client fails to answer a call after a defined number of rings. The Sphericall software runs on Windows servers and is available for approximately $150\/seat without public switched telephone network hardware interfaces for gateway services.\u2022 From the Web-based collaboration angle, First Virtual Communications announced that its Conference Server will support establishment of multiprotocol, multiparty voice and video sessions, including SIP, H.323-compliant clients and FVC's proprietary Web client, through Internet Explorer 5.5 or later.At a recent Microsoft press event, FVC demonstrated that when peered with a SIP registration server, such as Microsoft's upcoming real-time communications server, Greenwich, its Conference Server could include a Windows Messenger client in a Web-based conference and, from the Click to Meet graphical user interface, initiate sharing services between participants and the server.Similarly, Latitude Communications, which specializes in voice and Web conferencing, is partnering with videoconferencing hardware vendor Radvision to expand its existing MeetingPlace platform to support Messenger.When users have MeetingPlace privileges and their network manager installs the upcoming support for SIP, a new tab will appear on their Messenger interface. The MeetingPlace tab will display the user's previously scheduled meetings, offer access to the server's resources for scheduling future meetings or instantly establishing a MeetingPlace data and voice session. With a Radvision multipoint conferencing unit, the meeting also can include SIP video-enabled participants.The final caveatDespite the potentially feature-rich user experience, Messenger-based communication faces formidable challenges in the enterprise.In other words, network execs aren't likely to turn on new features until they are satisfied that these SIP-aware products and services offer sufficient security, archiving and control of network resources.Questions for your vendor 1. What type of security mechanisms will there be to authenticate users and to protect data? 2. What type of management tools will I have to monitor and control the system? 3. What type of archiving system will be set up to store and retrieve instant messages? 4. How much user training will I need? 5. How much staff time will be required to run the system? 6. What is the extent of the costs, including things like desktop video cameras and microphones. Perey is president of Perey Research and Consulting in Placerville, Calif., and a member of the Network World Global Test Alliance. She can be reached at email@example.com.