In a client/server arrangement, network services are located on a dedicated computer called a server. The server responds to the requests of clients. The server is a central computer that is continuously available to respond to requests from clients for file, print, application, and other services. Most network operating systems adopt the form of a client/server relationship. Typically, desktop computers function as clients and one or more computers with additional processing power, memory, and specialized software function as servers.

Servers are designed to handle requests from many clients simultaneously. Before a client can access the server resources, the client must be identified and be authorized to use the resource. This is done by assigning each client an account name and password that is verified by an authentication service. The authentication service acts as a sentry to guard access to the network. With the centralization of user accounts, security, and access control, server-based networks simplify the administration of large networks.

The concentration of network resources such as files, printers, and applications on servers also makes the data generated easier to back-up and maintain. Rather than having these resources spread around individual machines, resources can be located on specialized, dedicated servers for easier access. Most client/server systems also include facilities for enhancing the network by adding new services that extend the usefulness of the network.

The distribution of functions in the client/server networks brings substantial advantages, but it also incurs some costs. Although the aggregation of resources on server systems brings greater security, simpler access and coordinated control, the server introduces a single point of failure into the network. Without an operational server, the network cannot function at all. Servers require a trained, expert staff to administer and maintain. This increases the expense of running the network. Server systems also require additional hardware and specialized software that add to the cost.

Figures and summarize the advantages and disadvantages of peer-to-peer vs. client-server.

Lab Activity Lab Exercise: Building a Hub-based Network This lab is to create a simple network with two PCs using a hub, identify the proper cable to connect the PCs to the hub, configure workstation IP address information, and test connectivity using the ping command.

    

Lab Activity Lab Exercise: Building a Switch-based Network This lab is to create a simple network with two PCs using a switch, identify the proper cable to connect the PCs to the switch, configure workstation IP address information, and test connectivity using the ping command.

    

Web Links Client/Server http://searchnetworking.techtarget.com/sDefinition/ 0,,sid7_gci211796,00.html The Basic of Switching http://www.vtac.org/Tech/TDbasics_of_  switching.htm