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Scaling to Larger Networks 275

Single Domain

This domain model is the simplest because the network has only one domain. In the single
domain model, all users and groups reside in one domain. Because only one domain exists, no
trusts are necessary. A single domain is OK for small to medium networks that need centralized
administration of accounts and resources. Theoretically, the user base can handle up to 40,000
users. In practical usage, the single domain model performs poorly if the number of users and
groups in the domain overwhelm the server's resources. In addition, browsing is slower if the
domain has a large number of servers.

Complete Trust

This model is designed for companies that do not have a centralized IS organization. For those
who seek the ultimate in distributed management, complete trust is the answer. The complete
trust model distributes the administration of users, groups, domains, and resources. The
complete trust model is the easiest to understand, but it lacks security and can be the most
difficult to manage. Everybody trusts everybody. Every domain in the network trusts every
other domain. The following formula produces the number of trust relationships required to
implement a complete trust:

n (n 1) = trust

For example, 10 (10 1) = 10

× 9 = 90. In other words, 10 domains would require 90 trust

relationships. Now that's a lot of trust!

NOTE

The number of trusts can be a factor in determining an appropriate domain structure because
structures with the fewest number of trusts are the easiest to manage.

Figure 8-10 depicts the complete trust model.

Figure 8-10

Complete Trust Model

Domain

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