Domains predate the workgroup by a considerable time-span in computer years. Older computer systems used a centralized mainframe and terminals attached to the mainframe to perform work. In many respects, a Windows domain works the same way as these systems of old. Yes, the workstations connected to the server have intelligence and perform some work locally, but the central computer maintains a firm grip on everything that goes on with the network. That’s why administrators call servers that provide services in a domain a domain controller — the server controls the environment completely.
Don’t get visions of “Big Brother” at this point. Yes, the domain controller exercises considerable control over the network, but many users won’t even notice the difference. The difference is more noticeable to the administrator than it is to the user in most cases. Domains are extremely useful in some situations. You have many reasons for using a domain. These reasons include
• Better security
• Centralization of control over users, machines, and resources
• Improved organizational capability
• Enhanced performance through efficient resource usage
• Superior reliability on large networks
This list may lead you to believe that domains are far superior to workgroups, and they are, in some respects. However, you always have to consider both sides of the coin. Although domains provide you with all these benefits, you must also bear the cost of using them. These costs include
• Increased complexity, which can increase administration time and result in more errors
• Loss of certain Windows Server 2008 features, such as Internet Connection Sharing (ICS)
• Required use of some features, such as Active Directory
• Significantly increased training costs
• Decreased flexibility in some areas, such as the ability to create ad hoc connections when required
• The number of users makes a difference. (I’ve seen networks of up to 100 users work just fine as a workgroup, but 75 users is probably a more practical upper limit.)
• Application types, such as databases, require better security and control, which means that you may need a domain with fewer users.
• High-network-bandwidth applications require additional resources, which means you may need a domain with fewer users.
• High-security applications normally require a domain no matter how few or many users you have.
• Shared resource applications, such as word processing, don’t require a domain in most cases unless you have a large number of users that must collaborate on content.
• Services such as file sharing and printing don’t usually require a domain.
• Power users generally work better in a workgroup setup.
• Novice users may not require a domain, but the domain environment can sometimes prevent them from making as many mistakes.
• Scientific and other highly collaborative applications don’t require a domain unless the application has significant security requirements. (The use of a domain will inhibit the users in this case.)
• Networks with high growth rates may not require a domain today, but will likely need one tomorrow, so installing the domain at the outset is less confusing for end users.
Domains are a good networking solution, but only in certain situations. In some cases, a workgroup is the right choice because the number of users doesn’t warrant a domain. Of the factors that you should consider when choosing between a domain and a workgroup, the centralized management capability is the most significant reason to use a domain, whereas the increase in complexity is the most significant reason not to use a domain. No magic number of users exists for determining when to use a domain. The point at which a domain becomes necessary is a combination of the following user factors:
Source of Information : For Dummies Windows Server 2008 For Dummies