|  |  | Overview

Now that you have studied wide-area network (WAN) technologies, it is important to understand that WAN connections are controlled by protocols that perform the same basic functions as Layer 2 LAN protocols, such as Ethernet. In a LAN environment, in order to move data between any two nodes or routers, a data path must be established, and flow control procedures must be in place to ensure delivery of data. This is also true in the WAN environment and is accomplished by using WAN protocols such as Point-to-Point Protocol. In this chapter, you will learn about the basic components, processes, and operations that define Point-to-Point Protocol (PPP) communication. In addition, this chapter discusses the use of Link Control Protocol (LCP) and Network Control Program (NCP) frames in PPP. Finally, you will learn how to configure and verify the configuration of PPP. Along with PPP authentication, you will learn to use Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP).
| Threaded Case Study
Washington Project: Applying PPP

You learned about WAN design and developed the Washington School District's WAN design to allow connectivity between all sites in the district. Without a Layer 2 protocol, the physical WAN links have no mechanism to transmit data and implement flow control. In this chapter you will apply PPP as the data link-layer protocol to be used in the district WAN implementation.