Choosing the Best Administrative Model for Your Organization

Administrative models can help an IT organization begin to map out how IT resources and functions will be managed. Administrative models often follow a company's network architecture in terms of whether they are centralized, distributed, or a combination of the two. Many companies will find exceptions to this rule. Because administration in Windows Server 2003 environments can be granularly distributed, each model can be easily supported. This section will discuss centralized, distributed, and mixed administrative models.

It's a Lot Easier to Plan and Implement a Common Model in Early Active Directory Implementation Stages

The selection of the administrative model for an organization should be done early on in the design and planning phase of the Active Directory migration and implementation process. Although you can change administrative models, it's a lot easier to plan and implement a common model in early Active Directory implementation stages.

Centralized Administration

With centralized administration, most if not all of the IT resources and functions are administered from a central location. This often means that all the critical servers and IT equipment are also located in one physical site. Having a completely centralized IT architecture provides the advantage of greater control of all the resources. There is also a cost savings when compared to distributed and mixed models in that operating costs are limited to maintaining a single site. This has become an increasingly attractive model to companies trying to save costs by consolidating their resources. The disadvantage to a completely centralized architecture may be the need to maintain an expensive wide area network (WAN) to provide high bandwidth to remote sites. If there are many users supported remotely, providing acceptable network performance characteristics might outweigh the cost of distributing the IT architecture. In such cases, IT resources will be located in the remote sites.

Centralized Administration Can Be Maintained in a Distributed IT Environment

In this case, network resources might be located at remote sites, but the administration and management of those systems are still administered at the local site. Even with distributed IT resources, you can still gain most of the benefits of a centralized architecture by localizing administration. As the need for hands-on administration grows at the remote sites, IT organizations begin adopting a distributed administration model.

Distributed Administration

In a distributed administration model, the administrative resources are physically located at both the local and remote site(s). In a Windows Server 2003 environment, there are varying levels of distributed administration. In a completely distributed administrative model, all administrative functions at the remote sites are managed and performed by IT staff in those same geographic locations. In this scenario, the company might gain better remote site performance by having onsite support for IT resources. Even in situations where all IT resources are kept in a central location, a distributed administration model might still apply. For organizations with a very large data center, various administrative roles can be distributed to different IT groups. For instance, one group might have administrative rights over DNS, but another group administers DHCP services. Obviously, with a completely distributed administration, an IT organization loses some of the benefits inherent to the central administration model.

To preserve those benefits, many companies adopt a centralized/delegated approach to distributing administration. In these scenarios, limited administrative functions are delegated to remote administrators, whereas the overall administration of the network is managed from the primary central site. When centralized and distributed administrative strategies are combined, the mixed model begins to emerge.

Mixed Administration

The mixed model of administration will leverage the benefits from both centralized and distributed administration models. The mixed administration model benefits those companies that require distributed network architecture, but also want to maintain some level of central administration. Through granting permissions and rights for specific administrative functions to specific groups or users, the distribution of IT administration can be managed centrally . One example might be to have network security policies managed for the whole organization from the central site, but to have the user and computer account management administered at each remote site.

BEST PRACTICE: The Right Administrative Model

Best practices in deploying the right model for your organization can be summed up as follows :

• Centralize Whenever Possible: You achieve the tightest control and cost savings when all your IT resources and staff are located in the same location.

• Try to Maintain Centralized Administration: When user population or specialized applications force the deployment of remote IT resources, try to maintain centralized administration by managing these systems remotely.

• Delegate Administrative Tasks: When you need an administrative presence at the remote sites, maintain central control and delegate specific administrative functions to remote IT staff.

• Distribution of Administrative Tasks: Distribute full remote administration only as a last resort because this is often the most expensive solution with the highest degree of inconsistency across the IT organization.

Applying the Administrative Models

For most large size distributed organizations, adapting to a purely centralized or distributed administrative model is not practical. Finding the right combination of administrative strategies will be key in deploying a successful IT infrastructure. In making your administrative choices, you should design a strategy that balances between lowering cost and optimizing control (the centralized model) while meeting the needs of users and service level agreements (as in the distributed model).