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Case Study for SmallCompany Inc.

At this point in the chapter you have covered many vital considerations and ideas for successfully designing and implementing an Exchange 2000 deployment. Now, let's see how these items you just learned play out in some case studies. Three case studies follow, starting here with a study of SmallCompany Inc. Follow these studies to see how the principles of design and planning are played out in implementations for small, medium, and large companies.

Because the design of an Exchange 2000 environment varies based on the size and structure of an organization, this case study focuses on an organization in which the various components identified to this point can be applied to create a complete design of Exchange 2000.

In this example, SmallCompany Inc. is a recently formed alternative energy company that develops generators that use a variety of non-traditional forms of fuel. Its objective is to become a leader in the development of environmentally sound, energy producing products. SmallCompany Inc. has developed a proprietary technology that enables it to quickly generate new product candidates, and the company is growing quickly. In July of 2001, SmallCompany Inc. completed its initial public offering and is currently listed on the stock exchange.

SmallCompany Inc. has 250 total users located in a single facility with a network topology sketched out in Figure 3.6. Approximately 40 users are mobile (that is, they access the network from a variety of locations). The IT staff consists of four network administrators and help desk support.

Figure 3.6 SmallCompany Inc. network topology diagram.

Current DNS Implementation

In this example, domain name service (DNS) is not being used within the organization. The company's domain is hosted by an Internet service provider (ISP) and is authoritative for that domain. Network clients are configured to refer to the company's firewall for external DNS name resolution. The firewall acts as the DNS proxy for all external requests.

Business Requirements

SmallCompany Inc. has identified the following business requirements for its reason to migrate to Exchange 2000:

  • A more reliable and efficient enterprise mail system

  • Lower Total Cost of Ownership (TCO)

  • Scalability

  • Complete communication platform

  • The ability to centralize administration

  • A simple implementation to manage

  • The ability to provide the highest level of performance and reliability and still be cost effective

  • A remote access solution that leverages the Internet

Deployment Roles

For SmallCompany Inc., there are four IT staff members responsible for managing the day-to-day tasks for both infrastructure and end-user support. The company has a limited budget and although the IT staff members have strong technical backgrounds, they have limited exposure to Exchange 2000 technologies. The organization has decided to allocate funds in the budget to hire an outside consulting firm for planning and design assistance.

SmallCompany Inc. has determined that because they have limited staff, the roles and responsibilities have been divided according to the following matrix:

  • Product Manager/Project Manager/Training and Support Coordinator: SmallCompany Inc. internal IT Director

  • Design Architect: External contractor

  • Quality Assurance Coordinator: External contractor

  • Technology Implementation Team: Internal IT staff

DNS Implementation

The Design Architect contracted by SmallCompany Inc. has recommended that the organization implement the Active Directory integrated DNS model. This design recommendation was made in an effort to minimize administrative overhead and avoid the need to manage a separate DNS implementation. In addition, DHCP will be migrated from the existing installation to Windows 2000 DHCP. By using Windows 2000 DHCP, Windows 2000 and down-level clients will automatically be registered by Windows 2000 Dynamic DNS (DDNS). This configuration also eliminates the need to deploy an additional server to support down-level clients (Windows NT) that require WINS.

AD Domain Model Used

Based on the functional requirements established by SmallCompany Inc., the single domain model would be appropriate. An effective, yet simple, topology allows the organization to preserve the current administrative structure that is in place today. All users and resources are restricted to a single facility. For this reason, replication is not a design factor.

Define Storage Groups and Multiple Databases

The storage solution for SmallCompany Inc. includes a single server, single storage group configuration. This server hosts all Exchange-related components. RAID-5 is configured for the mail and public stores and a separate RAID-1 drive set houses the storage group transaction log set. A separate RAID-1 pair contains the Windows 2000 operating system and other related services or applications. In addition, there are two databases configured within the storage group where half the users use one database for the storage of their mailboxes and the other half use the other database for their mailbox storage.

The Design Architect chose this configuration based on the prioritized business requirements. The issue of reliability and total cost of ownership was more important than efficiency. The solution needed to be scalable to accommodate the projected growth of the company. This configuration satisfies that requirement. Scalability and cost efficiency will be achieved through the use of RAID-5, which in turn, lowers the total cost of ownership.

Administrative Groups

SmallCompany Inc. has a single IT administrative group that manages the entire infrastructure for the organization. Once implemented, this group will be the same group that manages the Exchange 2000 installation. For that reason, they will be implementing the centralized routing management solution. There will be only one defined administrative group.

Routing Design

This decision was not a difficult one. Because of the organization's simple and flat network topology, the single routing group was chosen. A single routing group assumes that link speeds between all servers within the routing group are of high bandwidth (T1 or better). SMTP is used to route messages between servers within the same routing group. Delivery is transported in a point-to-point fashion.

However, there are a couple of caveats to this design. For instance, if a single message is destined for recipients on five different servers, point-to-point communication causes the message body to be sent five times. Also, because there is no mechanism to throttle the traffic, the single routing group configuration is not an efficient solution for an organization that lacks high-bandwidth data pipes.

Remote Access

SmallCompany Inc. implements a single front-end server for remote e-mail access for the entire organization. This server resides in the DMZ. The IT group registers a DNS hostname that can be used by remote mail users to attach to the front-end server. For example, the remote user would enter http://webmail.smallcompanyinc.com/exchange to establish an Outlook Web Access session.

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