31 Days Before Your CCNA Exam

334 31 Days Before Your CCNA ExamPPP Configuration and VerificationFor this section, we will use the topology shown in Figure 3-4.Figure 3-4PPP Topology192.168.1.1Fa0/0R1192.168.2.1S0/0/1 192.168.2.2S0/1/1R2192.168.3.2Fa0/1Basic PPPConfiguring PPP requires only the encapsulation ppp command on both ends of the link.Example 3-2 shows a simple configuration using the two routers shown in Figure 3-4.Example 3-2Basic PPP Configuration and VerificationR1(config)#interface serial 0/0/1R1(config-if)#ip address 192.168.2.1 255.255.255.0R1(config-if)#encapsulation pppR1(config-if)#clock rate 64000R1(config-if)#no shutdown%LINK-5-CHANGED: Interface Serial0/0/1, changed state to downR2(config)#interface serial 0/1/1R2(config-if)#ip address 192.168.2.2 255.255.255.0R2(config-if)#encapsulation pppR2(config-if)#no shutdown%LINK-5-CHANGED: Interface Serial0/1/1, changed state to up%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1/1, changed state to upR2(config-if)#endR2#show interfaces serial 0/1/1Serial0/1/1 is up, line protocol is up (connected)Hardware is HD64570Internet address is 192.168.2.2/24MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255Encapsulation PPP, loopback not set, keepalive set (10 sec)LCP OpenOpen: IPCP, CDPCPThe show interfaces command at the bottom of the example shows the normal output when thelink is up and working. A few lines into the output, the highlighted phrases show that PPP isindeed configured, and that LCP has completed its work successfully, as noted with the “LCPOpen” phrase. Additionally, the output lists the fact that two CPs, CDPCP and IPCP, have also successfullybeen enabled—all good indications that PPP is working properly.