So what is the main difference between these two products and when do you use one over the other?
The Two flavors of Live Communication Server 2005
The Standard Edition is designed for smaller organizations with up to a maximum of 15,000 users while the Enterprise Edition is for larger organizations supporting upwards of 125, 000 users.
Live Communications Server 2005 Standard Edition
LCS Standard Edition is a standalone server with the Microsoft Desktop Engine as opposed to SQL located on the local box. LCS Standard Edition is designed to run against a dual proc box. Standard Edition is completely self-contained and does not require an external SQL Server to operate.
Live Communications Server 2005 Enterprise Edition
LCS Enterprise Edition uses distributed processing in a two tiered approach with LCS servers connected to a centralized storage on a Back-End Database.
LCS Enterprise Edition is for a large enterprise, providing higher scalability and better availability and failover capabilities. For deployments requiring high availability and scalability, the notion of a "home server" or Front-End server is introduced.
- LCS Enterprise Edition Front-End manages client connections, presence, and the remaining real-time communication features like instant messaging.
- LCS Back-End Database, running Microsoft SQL Server 2000 SP3a, can be clustered for higher availability.
When both a Frond-End Enterprise Edition Server and the Back-End Database are used they are referred to as a pool. A pool is also known as a collection of Enterprise Edition Servers that are connected to a central LCS Back-End Database.
To utilize distributed roles the first role will include Enterprise Edition, which will handle the Front-end operations of Live Communications Server. This role is commonly referred to as the "home server" within Live Communications Server design. The remaining roles compliment this front-end architecture element.
Users register to the Enterprise pool and are directed to a specific server within the pool by a hardware Load Balancer that distributes the load to these servers. Load Balancers expose a single VIP address (Virtual Internet Protocol address) that is used by the clients to access this pool of servers. Each server running LCS Enterprise Edition within the pool is responsible for connection processing, security and authentication, protocol processing, and server applications. The static data, such as contact lists and access control lists are stored as persistent data on the LCS Back-End Database.
In the process of authentication the user will register on one server in one instance and a different server at a separate time. In the case of the desktop, mobile and web interfaces being used simultaneously on might be signed into different servers simultaneously.
Reference to User Interfaces
Microsoft Office Communicator 2005
http://www.microsoft.com/office/livecomm/prodinfo/faq.mspx#EWDAC
Microsoft Office Communicator Web Access
http://www.microsoft.com/office/livecomm/prodinfo/faq.mspx#EOFAC
Microsoft Office Communicator Mobile
http://www.microsoft.com/office/livecomm/prodinfo/faq.mspx#ERGAC
LCS Server Roles and Pools
The user data is resident in the LCS Back-End Database is contained on the server that runs SQL Server 2000. This database contains the records that hold static data previously portrayed and dynamically updated data like the endpoints and active descriptions for a user. It also provides runs for a set of stored procedure calls that form the core of the operational software. An LCS pool is networked to the Back-End server using a high-speed network. This LCS pool also runs the UR (User Replicator) software to provide a connection to Active Directory (AD) so user account information can be synchronized between the LCS Back-End Database and AD. There are additional roles that will be used in a LCS Pool. These roles are known as Director, Access Proxy, Proxy and Archiving Service.
So what is a Director?
The Director uses a unique configuration mode of either Standard Edition or Enterprise Edition Server that is not used to home any users. Directors provide authentication and authorization to remote clients (the enterprises own users connecting from outside the firewall using the access proxy) and route clients to their home server. Access Proxies will never communicate to AD by design and, therefore authenticate users themselves.
How about an Access Proxy?
The Access Proxy permits federation, or the ability to communicate with users in another organization; or remote user access, which is the ability of users to connect to internal LCS Servers from an external location. The Access Proxy is a specially configured proxy that is designed to operate in the perimeter or DMZ. The Access Proxy will have restricted routing rules that separate and protect the outside edge of the network from the inside edge, providing a central platform to manage and enable cross-organization, domain-based policies. An Access Proxy never requires AD as it only manages SIP domains, not users. Access Proxy only requires a Standard Edition license, although this server role is provided for both Standard Edition and Enterprise Edition installations.
What is a Proxy?
LCS Proxy provides a method for customizing deployment and developing applications. Static routing rules can be configured as well as more complex routing applications. Proxy again requires a Standard Edition license, although this server role is provided for both Standard Edition and Enterprise Edition installations.
And finally what is the Archiving Service?
The Archiving Service consists of a server that contains archived instant message conversations for users configured for archiving. For archiving to be in place archiving must be enabled on each LCS Server hosting users that need archiving. The Archiving Services use the SQL database on the Back-End to store the archived data. The Archiving Service enables companies to comply with corporate and government policies that require the retention of instant messaging communications.
Live Communications Server Feature Comparison
http://www.microsoft.com/office/livecomm/prodinfo/compare.mspx
