Datasheet
The Live Communications Server Proxy provides developers with the capability to write custom real-
time applications that leverage the LCS Application Programming Interfaces (APIs). Exposing these
components also enables developers to integrate existing Line of Business (LOB) applications to take
advantage of the communication, collaboration, and presence features of the Live Communications
Server service. For example, integrating LCS with mapping and Geographical Information System (GIS)
systems, mobile applications, or even workflow applications provides existing applications with
enhanced features.
The Live Communications Server Proxy also provides branch office access to an LCS environment. By
using an LCS Proxy, instead of having remote offices all connect through an LCS Access Proxy directly,
the LCS Proxy can compress the packets sent from these users to the LCS server environment. The LCS
Proxy then sends these client requests to the LCS Access Proxy to route the users to their appropriate
LCS server.
Live Communications Server Director
While LCS Access Proxy Servers enable remote connectivity into a Live Communications Server envi-
ronment, the Live Communications Server Director performs the authentication of the remote user
within Active Directory. By design, the Live Communications Server Access Proxy Server does not
access the internal directory because an Access Proxy is meant to live on the outside edge of the
network. The Director receives the requests from the Access Proxy and then authenticates and transfers
each user to a Live Communications Server Standard Edition or Enterprise Edition server.
Figure 1-3 shows a diagram depicting the Live Communications Server Director within a Live
Communications Server environment.
Although the Live Communications Server Director is not a required component of a Live Communications
Server environment, it is heavily recommended. It helps buffer external communications and handles
integration with telephony-based services such as the PBX and PSTN services, which most enterprise
and mid-market companies utilize. The Live Communications Server Director provides a layer of
abstraction for the Live Communications Server Access Proxy as well so that custom applications that
leverage the Live Communications Server APIs do not have direct access into the system. With a Live
Communications Server Director deployed, these applications will have a route configured within the
Live Communications Server Director console, which allows for better management and control of the
internal Live Communications Server environment.
Live Communications Server Front-End Servers
Live Communications Server 2005 SP1 Enterprise Edition is deployed using the concept of a pool of
servers. That may be alarming to customers who are already concerned about the amount of required
servers to support a Live Communications Server environment, but in order to provide a scalable and
highly available solution, the pool architecture enables a Live Communications Server environment with
a redundant amount of servers, enabling servers to be removed and replaced in case of system failure or
to support growth, i.e., adding more users to the system, easing the pain of enterprise Information
Technology administrators. A Live Communications Server pool comprises Live Communications Server
pool servers (Front-End) Enterprise Edition Servers and Live Communications Server Back-End SQL
Servers. Each Live Communications Server pool can provide service for up to 100,000 users. Each LCS
pool server communicates with other servers in the pool to provide highly available user support. This
communication occurs over a newly introduced transport called Mutual Transport Layer Security (MTLS),
which is an enhanced version of Secured Sockets Layer (SSL) that provides encryption of the communi-
cation between users and servers.
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Introducing Microsoft Unified Communications
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