A domain model in Microsoft Windows NT in which every domain trusts every other domain with two-way trusts. The complete trust model is rarely implemented in Windows NT–based networks unless the motivation for using Windows NT is being driven from the bottom up.
For example, if a number of individual departments start implementing domains, the company might soon find itself implementing the complete trust model in order to make administration of these domains more efficient. This model also might be used in a situation in which two companies using Windows NT merge into a single company.
Because of the large number of trusts in a complete trust model, there are additional security concerns about who is able to administer what. The following table outlines the pros and cons of using this domain model.
| Advantages | Disadvantages |
| Scalable to any number of user accounts. | Complex to set up and administer. |
| Suitable for merging companies or organizations with no central MIS department. | Multiple local groups must be created in each resource domain. |
When you upgrade a Windows NT network based on the complete trust model to a Windows 2000 network, you can maintain the relative independence of each domain by migrating each domain to be the root domain of a domain tree. Each domain tree would have a single domain, namely the root domain. Two-way transitive trusts can then be established between the trees to form a domain forest.
Graphic C-25.Shown for Windows NT.