
	Designing and Building the Best Small Office Network From the Ground Up
	Creating Network Servers and Services In the first part of the chapter, we focused on basic connectivity issues. Now we pick up the task of creating useful network services that will help your organization use its computers more effectively. Here are some of the functions you will want to build into your network: File services. Almost all computer applications need to store data. In a freestanding computer, the local hard drive is the primary storage device. With a network, a server can be set up to store data in such a way that it can be shared by any person in the organization. File servers are the network computers that specialize in providing shared data storage. Through the interface built into the file server's network operating system, a network administrator can set up a variety of shared folders, and control access to them. A file server will generally also offer a private folder for each user. Data stored in that folder will not be visible to any other network user. Shared folders also will be created that can be accessed by several individuals. For each shared folder, the network administrator will determine who can read its information and who is allowed to create or modify it. All the major network operating systems offer a sophisticated environment for controlling access to information stored on the file server. Print services. Most organizations want the ability to have several individuals print to a single laser printer. It is far more efficient to purchase one or two high-end laser printers than to purchase low-end printers for each individual computer. Most network operating systems include the ability to manage network printing. Web servers. Given the trend toward Web-based computing, you will want to consider creating a Web server for your network. Web-based systems provide efficient ways to share information, either within the company's private network or externally via the Internet. Database and other application servers. Many businesses have specialized applications that operate from network servers. These applications may operate in conjunction with relational database systems or transaction processing environments, and are typically proprietary and industry-specific. You will need to work with the vendors that develop your applications to know the operating system, hardware and other requirements. CD-ROM servers. Many organizations have information products on CD-ROM or DVD that need to be shared. The ability to share a CD-ROM can either be integrated into an existing file server or a dedicated server can be established. General Network Organization: Peer-to-Peer versus Client/Server In a network, computers tend to be considered either clients or servers. A client uses network services and a server provides them. These roles are not mutually exclusive, and some computers might operate as clients in some ways and as servers in others. The client/server network model relies on dedicated servers that deliver services to network clients. This model makes clients and servers separate and distinct. Servers are built from larger and more powerful computer systems, and are dedicated to providing network functions. Clients rely on servers, and do not provide network services to other computers. The advantage of this approach lies in being able to concentrate resources on the server computers to ensure that they are sufficiently powerful to meet the needs of many users, have adequate security features and be highly reliable. In a peer-to-peer network, computers can act as both clients and servers. Such a network would use non-dedicated servers that simultaneously double as client computers. Modern desktop operating systems such as Windows NT Workstation, Windows 95 and MacOS all support the ability to offer various network services in addition to providing a desktop environment. Using these operating systems, you can easily construct a peer-to-peer network where computers can function both as someone's desktop computer and offer resources shared on the network. A laser printer connected to one person's desktop computer could be defined as a network resource shared by the entire workgroup. Folders on a hard drive can be shared so others can use them to store files, and any desktop computer can also function as a Web server. Peer-to-peer networks can be economical since they eliminate the need for high-performance dedicated servers. On a small scale, peer-to-peer networks are relatively easy to set up. But once the scale exceeds more than a handful of computers, this style of networking can be very difficult to manage and does not provide the overall computing power to meet the organization's needs. When all the shared folders reside on a centralized file server, it is relatively easy for users to know where to go to find them, and the process of determining who can and should have access is manageable. When a large number of shared resources are located on the local hard drives of computers scattered throughout the organization, the matrix of possibilities for access and storage options becomes extremely complex. Performance issues also must be considered carefully in a peer-to-peer network. You must be sure that the computers involved have enough capacity to function well both as desktop computers and as shared network resources. The overall capacity of the computer must be adequate to serve both functions, and the competing tasks must be compatible. You could use the same computer for both your company's Web server and for your accounting department's workstation. But don't be surprised when access to the Web server slows to a crawl during tax season! Client and server functions can be combined only when the load of one of the two is relatively light. In reality, almost all networks have some characteristics of both organizational types. Even in large enterprise networks where critical business functions operate from centrally managed dedicated servers, there likely will be some desktop computers that also function as personal Web servers, that have folders published for use within a small workgroup or that share CD-ROM drives or printers. Such peer-to-peer resource sharing within enterprise networks is often unofficial and not sanctioned by the organization's IT department. In considering the basic setup of your small business network, carefully weigh the two options. Only the smallest networks can sustain a pure peer-to-peer approach. The more that you rely on the network for important business functions, the more you will need at least one dedicated server to guarantee fast, reliable access to network resources. If your environment at launch consists of less than half a dozen computers, then an initial network design in a peer-to-peer model might be reasonable, but plan to add a dedicated server as the network expands.