The Journey of a Network Engineer

Oct 25 2011   1:34AM GMT

How to Configure PPPoE?



Posted by: Sulaiman Syed
Tags:
Cisco
Configure
dhcp
how
interface
ios
PPPoE
router
virtual

This is one of the interesting things i have learned in past week. PPP over Ethernet (PPPoE). It is simple, yet tricky. It also has a limitation that network engineers might not know which will bring their network down.

Lets see a sample configuration of how to do it. First, configure one Router to be the client (dialer) that will ask for ip address through DHCP. We have configured Chap Authentication as well. Remember, that since we are running PPPoE, a virtual Dialer (interface) has to be configured with all the details, and lastly applied to the Ethernet interface.

R4(config)#interface Dialer1

R4(config-if)# ip address dhcp

R4(config-if)# encapsulation ppp

R4(config-if)# dialer pool 6

R4(config-if)# ppp chap hostname R4

R4(config-if)# ppp chap password 0 cisco

R4(config-if)#exit

R4(config)#interface Ethernet0/1

R4(config-if)# no ip address

R4(config-if)# pppoe enable

R4(config-if)# pppoe-client dial-pool-number 6

Second, we would configure the other Router with DCHP scope, and to be the server for PPPoE. We would also configure local username and password for chap authentication.

R6(config)#interface Virtual-Template1

R6(config-if)# ip address 155.1.146.6 255.255.255.0

R6(config-if)# peer default ip address dhcp-pool VLAN146

R6(config-if)# ppp authentication chap

R6(config-if)# exit

R6(config)#ip dhcp pool VLAN146

R6(dhcp-config)#   network 155.1.146.0 255.255.255.0

R6(dhcp-config)#exit

R6(config)#bba-group pppoe MYPPP

R6(config-bba-group)# virtual-template 1

R6(config-bba-group)#exit

R6(config)#interface Ethernet0/1

R6(config-if)# no ip address

R6(config-if)# pppoe enable group MYPPP

Lets try some pings

R6(config)#bba-group pppoe MYPPP

R6(config-bba-group)# virtual-template 1

R6(config-bba-group)#e

*Sep 22 18:30:41.911: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to up

*Sep 22 18:30:42.923: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed state to up

R6(config-bba-group)#exit

We notice that the ping command for size 1500 failed. Lets find out why.

R6#show int virtual-access 2.1

Virtual-Access2.1 is up, line protocol is up

Hardware is Virtual Access interface

Internet address is 155.1.146.6/24

MTU 1492 bytes, BW 100000 Kbit/sec, DLY 100000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, LCP Open

Open: IPCP

PPPoE vaccess, cloned from Virtual-Template1

Vaccess status 0×0

Keepalive set (10 sec)

72 packets input, 11972 bytes

70 packets output, 9604 bytes

Last clearing of “show interface” counters never

While at R4 we have.

R4#show int dialer 1

Dialer1 is up, line protocol is up (spoofing)

Hardware is Unknown

Internet address is 155.1.146.2/24

MTU 1500 bytes, BW 56 Kbit/sec, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, LCP Closed, loopback not set

Keepalive set (10 sec)

DTR is pulsed for 1 seconds on reset

Interface is bound to Vi1

Last input never, output never, output hang never

Last clearing of “show interface” counters 00:09:56

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations  0/0/16 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 42 kilobits/sec

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

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

18 packets input, 8890 bytes

77 packets output, 27485 bytes

Bound to:

Virtual-Access1 is up, line protocol is up

Hardware is Virtual Access interface

MTU 1500 bytes, BW 56 Kbit/sec, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, LCP Open

Stopped: CDPCP

Open: IPCP

PPPoE vaccess, cloned from Dialer1

Vaccess status 0×44, loopback not set

Keepalive set (10 sec)

DTR is pulsed for 5 seconds on reset

Interface is bound to Di1 (Encapsulation PPP)

Last input 00:00:08, output never, output hang never

Last clearing of “show interface” counters 00:04:29

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

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

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

76 packets input, 9688 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

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

88 packets output, 27611 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

It is shown that the MTU is 1492. Lets configure the MTU size at the dialer interface.

R4(config)#interface Dialer1

R4(config-if)# ip mtu 1492

Test ping again…

4#ping 155.1.146.6 size 2000

Type escape sequence to abort.

Sending 5, 2000-byte ICMP Echos to 155.1.146.6, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 8/12/16 ms

R4#

And it is working. Well, this is how PPPoE is configured, i hope this will help you when you configuring it.

 Comment on this Post

 
There was an error processing your information. Please try again later.
Thanks. We'll let you know when a new response is added.
Send me notifications when other members comment.

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Forgot Password

No problem! Submit your e-mail address below. We'll send you an e-mail containing your password.

Your password has been sent to: