In the traditional client-server model, a server provides data to one or more clients. In contrast, in a peer-to-peer network, every computer acts as a server and client to other computers on the network. As such, a particular computer might function as a server one moment and as a client the next (see Figure 3-4).
Figure 3-4 Communications Models.
The simplest type of computer network to construct in a small workgroup is a peer-to-peer network. In this model, every workstation acts as both a server and a client for every other workstation (see Figure 3-4). The disadvantage of the peer-to-peer model is uneven use of resources, in that the workstations with the most relevant content are accessed more often than workstations with less-frequently accessed content. The result is decreased performance for computational tasks of the frequently accessed workstations. Another limitation of this design is that data management is more challenging. Everyone in the workgroup must perform tasks such as archiving and updating antiviral utilities, for example.
In contrast, a client-server model employs a central server to provide programs and data files that can be accessed by client workstations on the network. An advantage of this model is that the network operating system running on the server provides for security, tiered access privileges, and no degradation of individual workstation performance because files are accessed from the server. In addition, the data and programs on the central server can be more easily and consistently archived, backed up, accessed, and shared.