Datasheet

Lab – Configuring Basic PPP with Authentication

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

41 packets input, 2811 bytes, 0 no buffer

Received 0 broadcasts (0 IP multicasts)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

40 packets output, 2739 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 unknown protocol drops

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

Step 3: Intentionally break the serial connection.

a. Issue the debug ppp commands to observe the effects of changing the PPP configuration on the

Branch1 router and the Central router.

Branch1# debug ppp negotiation

PPP protocol negotiation debugging is on

Branch1# debug ppp packet

PPP packet display debugging is on

Central# debug ppp negotiation

PPP protocol negotiation debugging is on

Central# debug ppp packet

PPP packet display debugging is on

b. Observe the debug PPP messages when traffic is flowing on the serial link between the Branch1 and

Central routers.

Branch1#

Jun 20 02:20:45.795: Se0/0/0 PPP: O pkt type 0x0021, datagramsize 84

Jun 20 02:20:49.639: Se0/0/0 PPP: I pkt type 0x0021, datagramsize 84 link[ip]

Jun 20 02:20:50.147: Se0/0/0 LCP-FS: I ECHOREQ [Open] id 45 len 12 magic 0x73885AF2

Jun 20 02:20:50.147: Se0/0/0 LCP-FS: O ECHOREP [Open] id 45 len 12 magic 0x8CE1F65F

Jun 20 02:20:50.159: Se0/0/0 LCP: O ECHOREQ [Open] id 45 len 12 magic 0x8CE1F65F

Jun 20 02:20:50.159: Se0/0/0 LCP-FS: I ECHOREP [Open] id 45 len 12 magic 0x73885AF2

Jun 20 02:20:50.159: Se0/0/0 LCP-FS: Received id 45, sent id 45, line up

Central#

Jun 20 02:20:49.636: Se0/0/0 PPP: O pkt type 0x0021, datagramsize 84

Jun 20 02:20:50.148: Se0/0/0 LCP: O ECHOREQ [Open] id 45 len 12 magic 0x73885AF2

Jun 20 02:20:50.148: Se0/0/0 LCP-FS: I ECHOREP [Open] id 45 len 12 magic 0x8CE1F65F

Jun 20 02:20:50.148: Se0/0/0 LCP-FS: Received id 45, sent id 45, line up

Jun 20 02:20:50.160: Se0/0/0 LCP-FS: I ECHOREQ [Open] id 45 len 12 magic 0x8CE1F65F

Jun 20 02:20:50.160: Se0/0/0 LCP-FS: O ECHOREP [Open] id 45 len 12 magic 0x73885AF2

Jun 20 02:20:55.552: Se0/0/0 PPP: I pkt type 0x0021, datagramsize 84 link[ip]

c. Break the serial connection by returning the serial encapsulation to HDLC for interface S0/0/0 on the

Branch1 router. Record the command used to change the encapsulation to HDLC.

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