R2(config)#username admin password cisco R2(config)#int s1/0 R2(config-if)#ppp authentication pap R2(config-if)# *Mar 1 00:46:07.907: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to down R1(config-if)#do ping 34.1.1.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 34.1.1.4, timeout is 2 seconds: ... Success rate is 0 percent (0/3) R1(config-if)#int s1/1 R1(config-if)#ppp pap sent-username admin password cisco *Mar 1 00:46:45.739: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/1, changed state to up R2(config-if)# *Mar 1 00:46:44.639: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to up R1(config-if)#do ping 34.1.1.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 34.1.1.4, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/20/24 ms