Organizations consider messaging and collaboration as mission-critical IT services that enable communication among employees, partners, and customers. A common goal of these organizations is to provide high-performance electronic messaging services that are consistently available, secure, scalable, manageable, and supportable. The planning process for an enterprise messaging system is frequently separated into the following distinct phases:

• Collect   In this phase, you assess business requirements and the current computing environment. Interviews with key business stakeholders can provide you with the business requirements. To assess the computing environment, the infrastructure team should collect IT documents that describe the present computing environment. With that information, the team can produce an analysis document that typically includes information about the IT architecture, the hardware and software being deployed, the existing operations procedures, and the logical and physical maps of the environment. The collection phase is especially important when transitioning an existing Exchange organization to Exchange 2007.
  
• Analyze   In this phase, you develop service design options. When you develop design options, consider the following areas:
  
  • Logical topology   What kind of Active Directory directory service forest topology will be implemented? Does your organization have or need more than one Active Directory forest? For more information about the logical topologies supported by Exchange 2007, see Logical Topologies.
    
  • Physical topology   How many servers running Exchange will be used? Does your organization have or need more than one Active Directory site, or more than one physical location? For more information about the physical topologies supported by Exchange 2007, see Physical Topologies.
    
  • Organization topology   What Exchange organization topology best fits your organization's size and needs? Does your organization have a single Exchange server or multiple Exchange servers? Do you have multiple Active Directory sites or forests? For more information about the organization topologies supported by Exchange 2007, see Organization Topologies.
    
  • Administrative model   What are your organization's administration model needs? Does your organization have or need a centralized administration model or a distributed administration model? For more information about Exchange roles and administration models, see Permission Considerations.
    
• Formalize   In this phase, you analyze and select service design options for implementation. For each design option, evaluate and document the trade-offs associated with the implementation. Based on these documented trade-offs, choose the design options that seem most appropriate, considering their interactions with, and dependencies on, the other design options. Then, in most organizations, it is typical to submit these options to decision makers and stakeholders for approval.
  
• Approve   In this phase, decision makers and stakeholders validate the messaging service design in a lab environment before approving deployment in a production environment. When the Approve phase is complete, planning of the production deployment path starts.
  

To design a successful messaging system based on Exchange 2007, you must understand the capabilities and limitations of the software and hardware upon which the messaging system is built. Whether you are developing a new Exchange 2007 messaging system, upgrading from a previous Exchange implementation, or migrating from an existing messaging system, you must balance the limitations of your directory service and network infrastructure with the capabilities of your messaging system, operating system, and user software.

In addition to following the guidance and recommendations in the Exchange 2007 product documentation, we also recommend that you review and consider following the additional guidance provided through the Microsoft Operations Framework (MOF), including the MOF Service Management Functions (SMFs). MOF provides operational guidance that enables organizations to achieve mission-critical system reliability, availability, supportability, and manageability of Microsoft products and technologies.

With MOF guidance, you'll be able to assess your current IT service management maturity, prioritize your processes of greatest concern, and apply proven principles and best practices to optimize your management of Microsoft Windows Server and Windows Server-based applications, such as Exchange 2007. SMFs provide operational guidance for Microsoft technologies. SMFs are a core part of MOF, which provides guidance through courses, services, guides, and other materials and media related to reliability, availability, supportability, and manageability of IT solutions. For more information about MOF and SMFs, see Microsoft Operations Framework. 

A variety of deployment paths are available for organizations that are planning on deploying Exchange 2007. Although they all achieve the same end result—a successful deployment of Exchange 2007—each path is slightly different because each customer's needs and starting points are different. Generally, though, there are common starting points and paths that cover all supported deployment scenarios, which includes new installs, transitions, and migrations.

We recommend that you review the best practices and necessary requirements for deploying Exchange 2007 in each scenario:

• Best Practices for Deploying a New Exchange Organization
  
• Best Practices for Transitioning an Exchange Organization
  
• Best Practices for Migrating from Lotus Notes to an Exchange Organization
  

Every Exchange organization is different, but most should match one of the scenarios shown in the following table. Each scenario has different considerations for you as you plan your deployment. Select the scenario that best describes your Exchange organization, and then click the corresponding topic link to learn more about the deployment considerations and options for your scenario.

Scenarios for deploying Exchange Server 2007