Cisco Networking Academy Program CCNA 1 and 2 Companion Guide, Revised part 27 is the Cisco approved textbook to use alongside version of the Cisco Networking Academy Program CCNA 1 and CCNA 2 web-based courses. The topics covered provide you with the necessary knowledge to begin your preparation for the CCNA certification exam (640-801, or 640-821 and 640-811) and to enter the field of network administration. | Page 229 Tuesday May 27 2003 9 01 AM Workstation and Server Relationships 229 Figure 4-41 Client-Server Model Peer-to-Peer Environment Computer Computer Computer Computer Client-Server Environment Server Workstation Workstation Workstation Mainframe Mainframe Environment Servers are designed to handle requests from many clients simultaneously as shown in Figure 4-42. Before a client can access the server resources the user must be identified and be authorized to use the resource. You handle this authorization by assigning each user an account name and password that is verified by an authentication service acting as a sentry to guard access to the network. By centralizing user accounts security and access control server-based networks simplify the work of network administration. The concentration of network resources such as files printers and applications on servers also makes the data they generate easier to back up and maintain. Rather than having these resources spread around individual machines they 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 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 requirement increases the expense of running the network. Server systems also require additional hardware and specialized software that add to the cost. Page 230 Tuesday May 27 2003 9 01 AM 230 Chapter 4 Cable Testing and Cabling LANs and WANs Figure 4-42 Server Resources Workstation Tables 4-4 and 4-5 .
