• Illustration: Windows Messenger 5.0

The first edition of Live Communications Server (LCS), Microsoft's server product for corporate instant messaging, person-to-person conferencing, and extending user presence information to other applications, is now available. Known during its beta as Real-Time Communications Server (code-named Greenwich), LCS is being promoted by Microsoft for its corporate instant messaging (IM) capabilities. Although future versions will provide presence and call routing information to large federated Voice-over-IP (VoIP) and remote conferencing systems, the first release lacks some important features yet commands an unexpectedly high price.

What Is LCS?

LCS is a new Windows server application that performs certain key services for the Windows Messenger 5.0 client (see the illustration "Windows Messenger 5.0") and other applications that use the Windows Real-Time Communications (RTC) Client APIs. These applications allow users to communicate and collaborate "live" with each other using IM, chat, VoIP, audio/video conferencing, or data conferencing sessions, plus receive notifications from server-based programs. Collaboration features in Office 2003 applications and the Windows SharePoint Services team site and portal product also use Messenger 5.0 and LCS to show the availability of others who have agreed to share "presence" information—for example, whether they're in their office, away from their desk, or do not want to be disturbed.

Exchange 2000’s Instant Messaging feature was Microsoft’s first attempt at corporate real-time communications, but it has serious shortcomings, such as no support for message logging, no message encryption, limited scalability, lack of conformance to standards, and limited interoperability with software and hardware from other vendors. Microsoft decided to abandon the Exchange-based approach and built LCS from scratch around a pair of emerging Internet protocols: Session Initiation Protocol (SIP), which helps session originators locate and deliver invitations to potential participants, and SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE), which allows SIP to handle IM.

In its first incarnation, LCS’s primary role is to help establish these sessions; once connected, the client-side software (which is not part of LCS) does most of the work. LCS performs the following primary services:

Contact/block list storage. LCS "home" servers store two kinds of information for each user: contacts, which define the set of other users with whom an LCS user wants to communicate; and allow/block lists, which restrict who is allowed to see a user's presence information and establish communications with that user. Because this information is stored on a server, users need maintain it in only one place, and it is available from any device running an LCS-compatible client program. (Note: LCS "contacts" are entirely different from contacts in Active Directory [AD] or Outlook.)

Security. Before parties can communicate with each other, they must first authenticate themselves with LCS using their normal AD credentials, and only those accounts with explicit LCS permissions get access to its services. Furthermore, both LCS and client programs can prevent network eavesdropping by using Windows' Transport Layer Security (TLS) in conjunction with digital certificates issued by the Windows public key infrastructure to encrypt and decrypt traffic between the clients and servers.

Registrar and presence status. Upon launch, SIP-based clients register with an LCS home server, providing their network address, the current user name, and the user’s presence status. This information is updated whenever presence status or the device in use changes, as when the user leaves his or her office and begins using a wireless device equipped with a SIP client. Other authorized parties (either individuals or programs) that want to establish a live communications session use this information to see who’s online and available.

Connection broker and relay. LCS acts as an intermediary in most, but not all, types of live communications traffic. Because users can have access to multiple communications devices, such as PCs, wireless Pocket PCs, cell phones, and VoIP phones, the appropriate device decision depends on which device the user is currently active and the type of live communications requested. LCS determines which device to contact the recipient on, then relays (forwards) the connection requests and text messages to the recipient’s client program. Since the caller may have a different LCS "home" server than the recipient, LCS servers intercommunicate and relay recipient presence information and messages between the various participants’ home servers.

Multiparty IM sessions. Because LCS acts as a message relay, LCS can also support multiparty chats by repeating IM messages to up to 32 recipients. However, this release of LCS does not support multipoint audio, video, or data conferencing—those kinds of data can be shared only between two participants. These non-IM live communication types use LCS only to establish a session; all further communications occur directly between the client peers.

Message logging. Because IM traffic is relayed through LCS rather than flowing directly between client applications, LCS can log the details and full text of instant messages to a SQL Server database. This is particularly valuable in situations where message logging is mandated by law (such as in the securities industry) or by corporate policy.

In addition to supporting client applications and devices that use the RTC communications protocols, LCS supports a server-side API that allows developers to build server applications that extend the functionality of LCS. For example, Siemens’ OpenScape product uses the LCS API to integrate the basic LCS services with e-mail, circuit-switched phone systems, multipoint conferencing systems, and a Web-based client.

Microsoft designed LCS Standard Edition version 1.0 for corporate use only. (Microsoft named the released product Office Live Communications Server Standard Edition but, at least for the 1.0 release, there will not be a separate Enterprise Edition.) Unlike the public .NET Messenger service (also known as MSN Messenger) or the third-party Reuters Messaging system (which is built on LCS), which allow individuals from multiple organizations to communicate, this release of LCS expects all users to be in the same AD environment and to connect either from inside the firewall or by using a virtual private network (VPN) connection over the Internet. However, the use of multiple LCS servers allow it to scale up to support large organizations, and even a single LCS server is capable of supporting up to 10,000 users.

Not a Full Conferencing Product

With Exchange 2003, Microsoft has dropped the IM support introduced in Exchange 2000 and intends for LCS to assume the corporate IM role. Furthermore, Microsoft has halted development on Exchange Conferencing Server, its product for intra-organizational online conferencing. Consequently, LCS has some big shoes to fill. Although its adherence to the SIP and SIMPLE standards is a big plus, it lacks some significant features of the earlier products and has further limitations, including the following:

No multiparty conferencing. Unlike Exchange 2000 Conferencing Server, LCS cannot host multiparty audio, video, and data conferences. Current Conferencing Server customers looking to upgrade will have to rely on LCS plus third-party add-ons from other vendors, such as Radvision or Siemens. Microsoft does not plan for LCS to fully take over the role of Exchange Conferencing Server, but instead plans to offer a future product based around the Office LiveMeeting technology it obtained as part of its acquisition of Placeware. This product will offer multipoint conferencing and will integrate tightly with LCS.

Not federated. In this release, LCS is limited to a single enterprise and cannot be federated as part of a larger communication network. This means that customers cannot use LCS to establish live communications with other organizations or with the public at large. However, enterprises with LCS can subscribe to an additional service, MSN Messenger Connect, for US$9 per user per year plus the cost of additional gateway software from FaceTime or IMLogic. This lets LCS users maintain their same corporate identities on the public .NET Messenger service, and offers other benefits, such as logging of messages between external and corporate participants. However, LCS and MSN Messenger Connect are not integrated; instead, the combined system takes advantage of Windows Messenger’s abilities to simultaneously connect to LCS and the .NET Messenger service. Microsoft has said that it is working on federation support so that users of a future release of LCS can exchange instant messages and presence with participants outside the firewall without requiring special third-party products.

No tools for analyzing logs. Even though LCS can write instant messages to a SQL Server database, it does not include tools for searching, viewing, and archiving these records. Customers must build their own or view the raw tables using a SQL query tool or the SQL Server administration console.

Limited clients. Windows Messenger 5.0 offers a number of improvements compared to its predecessor, such as application sharing and shared white-board support (previously only available in NetMeeting, which Microsoft now considers a deprecated technology). However, Windows Messenger is for Windows 2000 and Windows XP only—NT and Windows 9x users are out of luck. Although Windows CE 4.2 contains support for SIP and SIMPLE, the MSN Messenger client that ships with the Windows Mobile software for Pocket PCs and Smartphones connects only to the .NET Messenger service. Furthermore, LCS does not include a browser-based client, so users who lack access to a PC with Windows Messenger 5.0 cannot currently use LCS for live communications or to check the presence status of other users. However, a Web-based client for LCS is available from eDial that allows users with browser-equipped devices to establish IM sessions with other LCS users. Finally, before users with SIP VoIP phones can communicate with other LCS users, the organization must install additional third-party software and hardware support that layers on or integrates with LCS, such as recently announced products from NEC and Radvision.

Multiforest issues. Although LCS can be made to work in organizations having more than one AD forest, it is much more difficult. Customers can use the free Identity Integration Feature Pack for Microsoft Windows Server Active Directory or Microsoft’s Identity Integration Server (MIIS) 2003 (formerly called Metadirectory Server) to automatically create and synchronize AD "contact" objects in each forest such that each forest has records of all users in the enterprise.

To resolve some of these shortcomings and to extend the services provided by LCS to many more types of applications, such as call-center routing systems, Microsoft is relying on numerous partners that are developing client-side, server-side, and hardware products that integrate with LCS.

Migration Considerations

Even though the Windows Messenger 5.0 client is free, implementing IM has become much more expensive than when it was bundled with Exchange; the majority of customers considering LCS probably already uses Exchange, yet will have to buy LCS separately. LCS Standard Edition customers must buy a server license for each LCS server and a Client Access License (CAL) for each user or device that connects to LCS.

However, Microsoft has made a special provision for customers who purchased Software Assurance (SA) on Exchange prior to LCS’s ship date: they can get the LCS server and client licenses at no extra charge. Yet, unlike Exchange Server 2003, LCS requires Windows Server 2003; thus, all client computers or users connecting to LCS must have Windows Server 2003 CALs. Because these cost US$29 each (approximate U.S. volume pricing), customers who do not also have SA on Windows Server and are not planning a full-scale Windows Server 2003 deployment could still find the incremental cost of deploying LCS to be prohibitive.

LCS comes with tools and scripts that help organizations to migrate from Exchange IM to LCS, and the Messenger 5.0 client can simultaneously connect to both Exchange IM and LCS servers, so migration can be done gradually.

Pricing and Licensing

LCS server licenses have an estimated retail price of US$733, and a US$25 CAL is necessary for each user or computer running Messenger 5.0 or any other client program that accesses LCS. (Although the volume license "Core" CAL bundle includes an Exchange CAL, it does not include an LCS CAL.)

The LCS message logging option also requires a SQL Server 2000, for which a per-processor license runs approximately US$5,000. However, if a separate server is used for logging, it is not necessary to buy a second LCS server license for the logging server.

Microsoft also offers a US$9,766 External Connector license that allows nonemployees to connect to an LCS server without a separate CAL. This Connector cannot be used to provide hosted services to paid subscribers, and it must be obtained for every server that provides services to nonemployees. Since LCS requires users to be authenticated by AD and because the user needs VPN access, this Connector appears to be targeted at large organizations that either have hundreds of external contractors or partners having AD accounts in the organization’s directory or maintain an external-facing AD forest and network (separate from their corporate network) intended for use by customers.

Resources

For more background on LCS, see "Real-Time Communications Product and Kit" on page 15 of the June 2003 Update and "'Greenwich' to Support Windows IM, Real-Time Communications" on page 6 of the Nov. 2002 Update.

For more information on Windows Messenger, see "Instant Messaging Split to Continue" on page 22 of the Apr. 2003 Update and "Windows Messenger Moves IM, Conferencing in New Direction" on page 8 of the Aug. 2001 Update.

For more information on LCS, see www.microsoft.com/office/livecomm/prodinfo.

For more on Windows Messenger 5.0 and to download the product, see www.microsoft.com/windows/messenger.

For more information on Messenger communications limitations when passing through routers and firewalls that perform network address translation (NAT), see www.microsoft.com/technet/prodtechnol/winxppro/deploy/natfw.asp.

For developer information on the LCS SDK, see msdn.microsoft.com/library/en-us/rtcsrv/rtc/portal.asp.

For developer information on developing client applications to use LCS services, see msdn.microsoft.com/library/en-us/rtcclnt/rtc/real_time_communications_client_application_programming_interface.asp.