• Sidebar: Session Initiation Protocol

Windows Messenger combines the instant messaging (IM) capabilities of the MSN Messenger client with many of the conferencing and data-sharing features of NetMeeting. It blends these products with the help of a new real-time communication protocol, the Session Initiation Protocol (SIP), which is driving an important strategic shift for Microsoft's conferencing products and technologies. Windows Messenger will also be the client for an enhanced version of the MSN Messenger service that will sharpen competition with AOL.

The first version of Windows Messenger is not an adequate replacement for NetMeeting for "virtual meetings" involving multiple parties: it has no multicast support and cannot be used as a client for Exchange Conferencing Server 2000. However, it could be useful for enterprises that want to encourage advanced one-to-one collaboration between employees (such as videoconferencing or application sharing) without investing in an expensive infrastructure. It will be further enhanced as Microsoft expands its support for SIP, a nascent Internet Engineering Task Force (IETF) standard. (See the sidebar "Session Initiation Protocol".)

Combining Collaboration, Location

Windows Messenger completes the feature integration of NetMeeting and MSN Messenger, two client applications that have a history of working closely together.

When NetMeeting was first introduced in 1996, users had to know the IP address of the person they wanted to connect with to establish a videoconference or other collaborative session (such as application sharing). Within enterprises, this presented little problem. But to establish meetings over the Internet, users often had to look contacts up in public Internet Locator Service (ILS) servers, which, like freewheeling chat rooms, have no restrictions on who can see whom or the type of content that can be communicated. By 1999, Microsoft was maintaining six public ILS servers, but users complained that they were often crowded and slow, and unwanted invitations (often pornographic) were common.

In late 1999, soon after releasing MSN Messenger, Microsoft shut its ILS servers down (die-hards could still use third-party ILS servers). Instead, Microsoft encouraged NetMeeting users to use MSN Messenger to find contacts because, unlike ILS servers, MSN Messenger lets users control exactly who can "see" them online and who can add them to a contact list. To ease the transition, Microsoft made sure the two products were tightly linked: MSN Messenger contacts are automatically imported to NetMeeting's contact list, and MSN Messenger has a "Send an Invitation" option that can be used to initiate a NetMeeting session.

Windows Messenger Features

Windows Messenger offers a single interface that pulls together a set of conferencing, collaboration, and alert functions, some of which were included in MSN Messenger or NetMeeting, and some of which are brand new.

With Windows Messenger, users will be able to do the following:

• Add contacts and discover whether they are online.
• Initiate and invite contacts to participate in one-to-one collaborative sessions, which might involve text-based IM, videoconferencing, PC-to-PC voice communication, shared whiteboards, and/or application and file-sharing.
• Receive instant message notifications triggered to certain events, such as a stock price dropping below a certain point, through a new "Microsoft Alerts" service.
• Invite a trusted party (such as a corporate helpdesk or ISP support staff) to assume control of their PC, using Windows XP's new remote assistance feature.
• Place and receive IP-based phone calls with less annoying echo, thanks to new echo-cancellation technology in Windows XP that Microsoft licensed from PictureTel.

Unlike MSN Messenger, which currently offers PC-to-phone calls through a third-party service, Net2Phone, the first version of Windows Messenger will allow users to place calls only to other PCs. Microsoft expects that Windows Messenger's SIP-based architecture will make it easy for third parties, including telephone companies, to make PC-to-phone service available, and expects these services to appear within a few months of Windows Messenger's launch.

Windows Messenger and the Enterprise

Windows XP and Windows Messenger will provide a viable solution for companies that want to encourage real-time collaboration between users without investing in a conferencing infrastructure. Like MSN Messenger, Windows Messenger will serve as a client for both Microsoft's public MSN Messenger service (which will probably be renamed .NET Messenger Service) and the similar but separate IM service in Exchange 2000. When used with Exchange IM, Windows Messenger uses directory information in Active Directory to authenticate users; with the MSN Messenger service, it uses Passport identities.

Enterprises may be concerned about the security of staff using the public MSN Messenger service to look up contacts and establish sessions with external contacts, or may not want workers to engage in certain types of collaboration (such as bandwidth-intensive videoconferencing sessions). Microsoft plans to provide a SIP proxy and SIP registrar function within Windows .NET Server (code-named Whistler) that will allow administrators to set and enforce security policies, control exactly which Windows Messenger features each user can access, and restrict these features to internal use where appropriate.

Microsoft is also considering offering a separate Real-Time Communication (RTC) Server, which would be based on the same SIP server components included in Windows .NET Server but would offer additional security or deployment features. However, little additional information is available at this time about this potential offering.

Shifting Technologies

Windows Messenger uses SIP to establish and break down communication sessions. Because SIP works independently of the type of data (text, audio, video, etc.) used in a session, supporting SIP made it easier for Microsoft to combine IM-style discoverability with conferencing and data-sharing in a single client. In the long term, Windows Messenger's SIP support could enable myriad other scenarios. For example, a user could look up a contact in Windows Messenger, see that she is busy talking on her SIP-enabled desk phone, and initiate an IM session rather than trying to phone her. (For a more detailed explanation of SIP, and other possible scenarios it could enable, see the sidebar "Session Initiation Protocol".)

Although SIP can architecturally support multicast, the first version of Windows Messenger will have unicast support only. Unlike NetMeeting, Windows Messenger supports neither TAPI 3.0, Microsoft's current protocol for establishing multicast conferences without using a central server, nor H.323, the most common protocol for unicast audio- and videoconferencing. (H.323 can also be used to establish a session with three or more users by passing streams through a multipoint control unit, or MCU, on a server.)

This creates a decision point for companies interested in setting up virtual "meetings" between more than two people. These companies should note Microsoft's stated plans for the following products and technologies:

Exchange Conferencing Server (ECS) 2000 makes use of both TAPI 3.0 and H.323. Therefore, Windows Messenger cannot be used as a client for ECS 2000. Enterprises that already have ECS 2000 must continue to use NetMeeting, and should not consider the inclusion of Windows Messenger as justification for upgrading to Windows XP.

According to RTC Product Unit Manager David Gurle, Microsoft sees Windows Messenger eventually becoming the client for all types of collaboration and conferencing (although future versions of Office will also support some real-time communication scenarios). This suggests that the current NetMeeting-ECS 2000 pairing is slated for eventual retirement, although Gurle says this would not happen before early 2002 or late 2003, when and if Microsoft releases a second version of RTC Server with support for multiparty conferencing.

H.323. Enterprises evaluating any H.323-based conferencing system, including ECS 2000 and third-party solutions, should understand that Microsoft eventually hopes to phase out NetMeeting and that Windows Messenger will never support H.323 in any version.

Microsoft says it is working with third parties to create software that acts as a "bridge" between H.323 and SIP-based systems. Nonetheless, it might make more sense to buy a SIP-based alternative from companies like Cisco or Indigo Software, or wait for Microsoft's full range of SIP solutions, than to install a new H.323 system and risk future incompatibility with the built-in conferencing client in millions of future Windows machines.

Putting the Heat on AOL

Although Windows Messenger might create some confusion in the corporate market, it will help Microsoft in the consumer IM space. Here, Microsoft is in stiff competition against AOL's IM system, AIM—in Feb. 2001, MSN Messenger had 29.5 million global users (current numbers are about 32 million) versus AIM's 29.1 million, according to Jupiter Media Metrix. By adding new capabilities to its IM client, such as video communication, and allowing it to take advantage of new functionality in Windows XP, such as remote user control and acoustic echo cancellation, Microsoft provides a powerful incentive for users to sign up for the improved IM service, which will be introduced concurrently with the Windows Messenger client. (MSN Messenger clients will work with the new service, but will not be able to take advantage of the full range of features available.)

The successor to the MSN Messenger service will also require users to enter a Passport identity, just as MSN Messenger does today. Microsoft wants to build a large base of Passport users so it can then offer them fee-based services based on the HailStorm platform. In addition, IM itself is a crucial component of HailStorm-based services, as it provides a way for these services to notify customers of key events. It is likely that Windows Messenger will serve as the interface for managing these notifications, perhaps through the "Alerts" tab. (For background on HailStorm and its relationship to Passport and IM, see "HailStorm Fulfills Crucial Roles for .NET" on page 18 of the May 2001 Update.)

Finally, Microsoft may have laid a clever trap for AOL by integrating video support into its IM system. When AOL completed its merger with Time Warner in Jan. 2001, the Federal Communication Commission (FCC) laid down several conditions for approval of the merger. Among these was the stipulation that if AOL offers an "advanced" IM service—defined as including "one- or two-way streaming video communication"—then this service must be fully interoperable with at least three competing services within 180 days, either by using an IETF-approved standard (such as SIP) or through private agreements. Microsoft has been trying to convince AOL to open AIM to MSN Messenger users since 1999, reasoning that this would reduce the incentive of those new users who sign up for AOL simply in order to be able to send instant messages with friends and relatives who are also on AOL. If AOL responds to Windows Messenger by introducing its own video-enabled IM service (as third place IM operator, Yahoo, has already announced it would do), and the FCC holds to its original conditions, then Microsoft could finally achieve its goal of universal IM interoperability.

Resources

An excellent introduction to SIP can be found at www.sipcenter.com, a portal for promoting the commercial development of SIP software.

The SIP Forum, another consortium of organizations interested in driving SIP efforts, is at www.sipforum.org.

A more technical, noncommercial SIP resource is www.cs.columbia.edu/~hgs/sip/.

A good comparison of SIP and H.323 is at www.fokus.gmd.de/research/cc/glone/projects/ipt/sip.html.

The official IETF working group for SIP has a home page at www.ietf.org/html.charters/sip-charter.html and a supplemental home page at www.softarmor.com/sipwg/. Both pages contain links to drafts and proposals about SIP and related technologies, as well as contact information for the working group. The IETF working group for SIMPLE (SIP for Instant Messaging and Presence Leveraging) is at www.ietf.org/html.charters/simple-charter.html.

The press release announcing Reuters.NET Messaging is at about.reuters.com/nordic/pressreleases/art_22-3-2001_id526_country.asp. No more information is publicly available at this time.

For more about Microsoft Alerts, or to sign up as a beta tester, see alerts.microsoft.com.