MCSE Boot Camp Notes :(also CCNA CCNP Certification notes)

Server-Based Networking

In a server-based network environment, resources are located on a central server or group of servers. A server is a computer that is specifically designated to provide services for the other computers on the network. A network client is a computer that accesses the resources available on the server.

The server-based network model is more efficient for all but the smallest networks because hardware resources can be concentrated on relatively few highly-utilized network servers; client computers can be designed with minimal hardware configurations. A basic network client machine, for instance, might have a 486 processor and 8-16 megabytes of RAM. A typical server might have 32 megabytes of RAM (or more) and many gigabytes of file storage capacity.

Humans often specialize so that they become very good at one type of task. This approach has benefits for network servers as well. By dedicating a server to providing a specific set of services, it becomes possible to carefully tailor the computer to the requirements for that service, which results in optimal performance, simpler troubleshooting, and enhanced scalability. Both Exchange Server and SQL Server, for instance, are very resource-intensive services, and running these on a server that also provides file and print services often can result in decreased performance. Dedicating a single server to SQL Server, while expensive, greatly improves overall access to both the SQL databases and normal file and print requests.

A file server is a server that stores files on the network for users (see Figure 1.4). A user at a client machine can save a file to a hard drive located on the file server. If the user wants to access the file later, she can access the file from the client machine through a network connection to the file server. Maintaining a central location for file storage on the server makes it easier to provide a backup copy of important files and implement a fault-tolerance system, such as the RAID (Redundant Array of Inexpensive Disks) systems you learn about in Chapter 9, “Disaster Recovery.”

A print server manages access to network printing resources, thus enabling several client machines to use the same printer (see Figure 1.5). Because files and printers are so basic and so important to most networks, file and print services are very basic components of most network operating systems, and a single machine commonly acts (or is able to act) as both a file server and a print server.

For licensing purposes, Microsoft uses the term file-and-print server to refer to a machine that provides either file or print service functions because the use of either a printer or hard drive space on the server is considered a client connection. Licensing compliance is an important and often confusing part of network administration, which is covered in Chapter 8, “Managing and Securing a Microsoft Network.”

An application server is a server that actually runs an application (or part of an application) for the client (see Figure 1.6). Whereas a file server simply holds data (in the form of a file) that then is retrieved and processed at the client, an application server performs all or part of the processing on the server end. An application server might search through a large database to provide a requested record for a client. Or, an application server might be part of a client/server application, in which both the client and the server perform some of the processing.

The distinction between a file-and-print server and an application server is very important. Remember that a file-and-print server stores files, but it does not actually provide any processing. An application server provides processing and downloads the result to the client. A file-and-print server, therefore, generally requires a great deal of RAM, but is easy on the processor. An application server can be RAM intensive as well, but it definitely needs a more powerful processor.

Under the server-based model, a network administrator can easily control access to network resources. Through the network operating system, the network administrator can give or withhold permission for a user to access files, printers, and other resources located on the server.

The following network operating systems are designed to implement LANs based on server-based models: