ccna 200 301 book todd lammle

ccna 200 301 book todd lammle.322 Chapter 15 Identifying Other WAN Types DSL Connection Techniques. Not surprisingly, a number of new protocols have been created, including one that allows for the sending of PPP frames encapsulated inside Ethernet frames: the PPP over Ethernet (PPPoE) protocol.In order to send PPP frames between a client router and an ISP router, PPPoE essentially creates a channel on top of the DSL connection, as shown in Figure 15-13. DSL does not create a point-to-point link between these routers. With PPPoE (and related protocols), the routers logically create such a channel. From one perspective, the routers create and send PPP frames as if the link were a dial-up link between the routers. But before sending the frame over the entire physical link, the router encapsulates the frame in various headers, typically shown in the diagram as channel messagesHeader. PPPover Ethernet ConfigurationBecause of the ability to send and receive PPP frames between routers, the ISP is able to continue to use the same authentication mode while handling both analog and ISDN dialup. For this to work properly, the client and ISP router require some new configuration, including PPP configuration. The remainder of this topic will look at client configuration in general.For such a configuration, a slightly different approach is used. Imagine that you will see a configuration like the one shown in Figure 15-14. Then determine which parameters need to be matched. (Don't worry about building these configurations from scratch.) To begin to understand the configuration, keep the following facts in mind.. The configuration uses the dialer interface. which is a virtual interface used to create PPP channels. PPP configuration is performed on the dialer interface.. The physical Ethernet interface connected to the DSL modem will have a command to start PPPoE and link the interface to the dialer interface. Tip: For the purposes of this chapter. the details of the channel header are not important. However, the PPPoE channel header in this case has a typical Ethernet header, one for the PPPoE.PPPCHAP configuration typically defines one-way authentication, i.e., the ISP authenticates the client as shown in the example later. (The example in Chapter 12 shows bidirectional authentication.)The shorter header defined for use and the PPP frame (including IP packets)Customer router