Home > PPP over Ethernet (PPPoE) Tutorial

PPP over Ethernet (PPPoE) Tutorial

February 29th, 2016 in ROUTE Knowledge Go to comments

PPPoE stands for Point-to-Point Protocol over Ethernet. It is a means of establishing a point-to-point communications channel over an Ethernet network. But why do we need PPPoE? To understand the reason of PPPoE, we need to understand about Ethernet and PPP.

As we know, Ethernet is not a point-to-point but a multipoint technology (even when two devices are connected back to back). Ethernet is designed to allow multiple devices to share a common medium, called a “broadcast domain”.

While Ethernet is dominating at customer sides, Internet Service Provider (ISP) still like PPP because of authentication (PPP supports CHAP), accounting (checking customer’s bill), link management (ISP can use PPP to assign a public IP address for customer).

However, Ethernet and PPP do not support each other natively. To utilize the benefits of both Ethernet and PPP, a protocol was created: PPPoE, which allows computers to connect to an ISP via a Digital Subscriber Line (DSL) modem.

 

PPPoE_Connection.jpg

PPPoE creates a PPP tunnel over an Ethernet connection by encapsulating a PPP frame inside an Ethernet frame. The modem converts the Ethernet frames to PPP frames by stripping the Ethernet headers. The modem then transmits these PPP frames on the ISP’s DSL network.

Note: PPPoE client functionality can be installed on the DSL modem or on the user computer as a software. If PPPoE is implemented on the DSL modem, all the users behind will share the same PPPoE account of the DSL modem. If PPPoE is installed on user computer, each computer can access different services with different PPPoE accounts. Nowadays PPPoE client functionality is available in most operating systems from Windows, Linux to Mac OS.

The picture below shows the PPPoE Client dialog box to enter username and password before making a PPPoE connection on Windows OS.
PPPoE_Client_Windows.jpg

PPPoE Client on Windows

PPPoE simulates the dial environment where each PPPoE session is treated as a separate phone line, even though they are being transported on a single PVC.

PPPoE is composed of two main phases:

+ Active Discovery Phase: In this phase, the PPPoE client locates a PPPoE server, called an access concentrator. During this phase, a Session ID is assigned and the PPPoE layer is established.
+ PPP Session Phase: In this phase, PPP options are negotiated and authentication is performed. Once the link setup is completed, PPPoE functions as a Layer 2 encapsulation method, allowing data to be transferred over the PPP link within PPPoE headers.

PPPoE Configuration

PPPoE_Topology.jpg

Configuration at Client side (PPPoE Client)

interface Dialer 2
 encapsulation ppp
 ip address negotiated
 ppp chap hostname TUT
 ppp chap password MyPPPoE
 ip mtu 1492
 dialer pool 1

1. First we need to create a dialer interface with the interface Dialer 2 command. Any interface number is good. A dialer interface is a virtual interface and PPP configuration is placed on the dialer interface, not on the physical interface. The PPPoE client can be configured with a static IP address but in most cases it will be automatically assigned a public IP address by the ISP so we used the ip address negotiated command here.

The CHAP hostname and password must be configured so that the PPPoE Server can authenticate the customer. The hostname and password configured on the PPPoE Client router must match the hostname and password configured on the PPPoE Server router. In this case, the commands ppp chap hostname TUT & ppp chap password MyPPPoE tells the router to use “TUT” & “MyPPPoE” as the username & password to authenticate with the server.

The maximum transmission unit (MTU) should be reduced to 1492 (default of 1500) to accommodate the PPPoE headers: 6 bytes for the PPPoE header and 2 more for the PPP protocol ID. This prevents unnecessary fragmentation.

Finally this dialer interface must be linked to a dialer pool with the dialer pool 1 command.

Next we configure the physical interface.

interface Ethernet0/1
 no ip address
 pppoe enable
 pppoe-client dial-pool-number 1

2. The physical Ethernet0/1 interface that connects toward the PPPoE Server is enabled PPPoE with the pppoe enable command. This physical interface is then linked to dialer pool 1 with the pppoe-client dial-pool-number 1 command. Notice that the dialer pool number must match on the dialer interface and physical interface. In other words, the number in the commands “dialer pool <number>” (on Dialer interface 2) and “pppoe-client dial-pool-number <number>” (on interface E0/1) must be the same. But notice that the dialer interface number (interface Dialer 2) does not have to match the dialer pool number. This is how the dialer pool is connected to the interface dialer and physical interface:

dialer_interface_dialer_pool_physical_interface.jpgAlthough this way of configuration is a bit more complex than directly connecting physical interfaces into dialer interface but it makes the configuration more flexible. Imagine you have three dialer interfaces 2, 5, 10 and many physical interfaces. With dialer pools, you can easily change the physical interfaces which need to associate with your dialer interfaces without making change at the physical interface level.

multiple_dialers.jpg

In the next part we will learn how to configure PPPoE at Server side.

Comments
Comment pages
1 2 1472
  1. Tam
    August 25th, 2017

    HI Tan can you give me also the dumps for 300-101 at my email {email not allowed}

  2. Netw
    August 25th, 2017

    If you want gns3 lab for mpls vpnv4, check this
    https://garziadmostafa.wordpress.com/2017/08/21/mpls-vpnv4-configuration/

  3. Anonymous
    August 27th, 2017

    Please kindly share the recent dumps for ccnp route pleas, will really appreciate

  4. Steve
    August 30th, 2017

    Please send me the newest dumps via mail

    milenkovic23 @ hotmail . com

    Thank you.

  5. Anonymous
    September 3rd, 2017

    Hi guys,I am about to write my Routing and I really need your help.I need the RECENT Dumps for my exam. This is my email bimboy.conde at yahoo com Thanks in advance

  6. Anonymous
    September 4th, 2017

    Please email me the latest dumps. freyjasbooks at gmail com

  7. New470Qs
    September 12th, 2017

    Passed. 9xx…
    McQs: 3 or 4 new quesitons
    Labs all: same
    Drag and Drop: same
    Dumps470Qs

    https://docs.google.com/document/d/1cp2vtCYSV_21JTZF9D14Ua2gHdijtZjfIDuyVT1NyJg/edit?usp=sharing

    All exam questions are cover with Lab simulation and Drag drop in above link.
    Thankyou

  8. Anonymous
    September 13th, 2017

    kababakaramoko @ gmail . com please send me the last dump

  9. Anonymous
    September 25th, 2017

    Hi everyone,
    Could anyoven send me last version of ccnp dump that still valid please

    erkandursun1225 at gmail dot com

  10. CiscoDaddy
    September 26th, 2017

    Does anyone know if this is in the exam route 300-101?

  11. Spark
    October 3rd, 2017

    Can you send me the lastest dumps for all ccnp:routing and switching. Pls send it to “youngspark at ymail dot com”

  12. Anonymous
    October 4th, 2017

    Can someone send me the latest dumps at {email not allowed}

  13. Anonymous
    October 4th, 2017

    Can someone send me the latest dumps at “jaravind1 at yahoo dot co dot in”

  14. Anonymous
    October 13th, 2017

    Hi everyone,
    Could anyone send me last version of ccnp dump that still valid.

    questionmaster34 @ outlook dot com

  15. HIfly
    October 15th, 2017

    can somebody send me latest dump for ccnp 300-101 . iam planning to sit next week,
    would be very help

  16. HIfly
    October 15th, 2017

    can somebody send me latest dump for ccnp 300-101 . iam planning to sit next week,
    would be very help
    hifly.mansoor at gmail.com

  17. sky
    October 16th, 2017
  18. sahebul
    October 25th, 2017

    Hello everyone,
    Can anybody send me last version of ccnp route dump that still valid.
    sahebul.kt at g mail dot com

  19. r o
    November 5th, 2017

    This means YOU, personally, really should weight your words SERIOUSLY v w p, and I strongly advice you to delete this written defamation r o t x of both characters and a huge group of people who do not take slander and character assassination like this easily h g i o b. I do not know which organization you have got to back you up, but if you do not care about lawsuits in the multi-million dollar range, fine, just keep on what you are doing o y j f l. If you DO care about spending x-amounts of money to try and defend this CLEARLY written libel, then take my DELETE-advice. Your “Post” is now officially taken both copies and screen-shots of and digitally stored for later use and evidence. This is just a warning. We are antifa, we do not forget. {email not allowed}

    t

  20. XXX
    November 7th, 2017

    Passed with 918/1000.
    For valid dump, please contact on jknishant87 @ gmail . com

  21. KT
    November 8th, 2017

    Can someone send me some latest CCNP route and Switch Dumps please. kimdctorres @ gmail.com

  22. 1111
    November 15th, 2017

    Add a Comment

  23. kek
    November 19th, 2017

    antifa lol. Are all these people asking for dumps and posting links to google drive real? I cant figure out what is spam and what isnt. Can someone tell me if this web site has useful info for the route exam.. I am taking it the 29th and need to polish up my skills. thx

  24. maya
    November 24th, 2017

    hello everyone! just passed my 300-101 exam on my first try, I would like to thanks https://www.braindumpscerts.com/ for providing me the authentic exam study material.

  25. Nick
    November 29th, 2017

    DO NOT USE http://www.myexamcollection.com/ ITS A FAKE

  26. Ali
    December 3rd, 2017

    dont use vceplus dumps they are not good

  27. ALF
    December 6th, 2017

    Can someone send me some latest CCNP ROUTE 300-101, please!! {email not allowed}
    Thanks!

  28. SHEp
    December 6th, 2017

    Hello guys ,Can anyone share CCNP route dumps,am writing Jan,I will be happy to share them as well.#helpfellowengineersrise.

  29. SHEp
    December 6th, 2017

    email is htsepang at yahoo.com

  30. An 1
    December 7th, 2017

    Hey thanks for this site , it helped me to give my CCNP this year cleared by June

    Does any one can provide advices on how to crack Palo alto certification !

  31. Anonymous
    December 9th, 2017

    Hi i want to give exam CCNP routing next week 300-101 any suggestion regarding the dumps
    which someone recently use

  32. Anonymous
    December 9th, 2017

    or the website where i can buy from

  33. 690/1000
    December 15th, 2017

    Hi friend today I took the CCNP exam.
    There are few OSPF and EIGRP question, there are no BGP question. Most question in CCNP version 2 relate to new technology such as
    – IPv6
    – IPv6 DHCP
    – IPv6 access-class and filtering
    – NAT (NAT-PT, NATv6, NPTv6 etc.)
    – GRE Tunnel
    – DMVPN
    – NTP access restriction
    – netflow
    – pppoe
    – EVN VRF
    – uRPF

    In parts of Network Lab : OSPF evaluate , EIGRP evaluate , PBR , OSPF multi area , OSPF & EIGRP redistribute.

    In parts of Drag& Drop : frame relay , AAA , IPv6 NAT.

  34. hkjack
    December 27th, 2017

    Hi, could you plz send me the updated and latest CCNP route dumps
    to Vacharavit_ARM @ hotmail . com
    Thanks a lot.

  35. hkjack
    December 27th, 2017

    Hello to All
    I passed EXAM Today…….. 943 /1000

    Dump is super valid 100%

    GOT 100% Guaranteed VALID passing Material from below

    email:
    teledeal.pk at gmail

  36. palko30517
    December 28th, 2017

    Hello guys , could you send me valid dump for 300-101 ,please ?
    palko30517 at gmail dot com
    Thanks ;)

  37. SD
    January 7th, 2018

    Hello hkjack

    Bro Please Can you send me the Latest Dumps of (CCNP Route 300-101)

    {email not allowed}

    Thanks

  38. SD
    January 7th, 2018

    My email is (sd.rehman at gmail dot com)

  39. SD
    January 7th, 2018

    Sorry i mistakenly type my email id wrong so this is my right email id so bro please send me the (300-101) Latest dumps at my this email ID.

    (sd.rehman97 at gmail dot com )

    thanksss

  40. SD
    January 7th, 2018

    Hello guys , can anyone send me valid dump for 300-101 ,please ?

    sd.rehman97 at gmail dot com

    thankss

  41. CCNP Dumps
    January 8th, 2018

    Hi Guys,

    vincentitumele(at)yahoo.com,

    please kindly anyone with new dumps share with me, I’m taking the exam 15 Jan.
    please guys any help will do.

    thank you
    Vince

  42. Varadarajan
    January 8th, 2018

    Hello,

    can you pls share the latest CCNP route dumps, am planning to write the exam on 27th Jan.

    Pla mail to jv0055 at yahoo.co.in

  43. Spartan.Route
    January 8th, 2018

    Hi Guys,
    spartacus23 @ gmail . com,

    Can you please send me the CCNP ROUTE, I’m taking the exam Jan 28th.
    please guys any help will do.

    Thanks
    Spartan.Route

  44. timp
    January 8th, 2018

    Hi, anyone with the ccnp route dumps? my email is timp69 at mail (Not gmail) dot com

  45. Anonymous
    January 9th, 2018

    Hello Guys,

    Please send me the CCNP Route dump to this email address {email not allowed}. I am giving this exam within this week.

    Thank you

  46. Anonymous
    January 9th, 2018

    Anonymous January 9th, 2018
    Hello Guys,

    Please send me the CCNP Route dump to this email address writetoanish1(at)yahoo.com. I am giving this exam within this week.

    Thank you

  47. Anonymous
    January 9th, 2018

    Hello guys,
    Please send me the CCNP Route Dumps to ashritaash93(at)gmail.com.
    Thank you.

  48. sportkh
    January 9th, 2018

    please kindly anyone with new dumps share with me, I’m taking the exam 15 Jan.
    please guys any help
    {email not allowed}

    thank you

  49. sportkh
    January 9th, 2018

    khaled.jadabi att gmail and yahoo

  50. sportkh
    January 9th, 2018

    please kindly anyone with new dumps share with me, I’m taking the exam 15 Jan.
    please guys any help
    khaled.jadabi att gmail & yahoo

    thank you

  51. Hi Guys! Route Exam
    January 9th, 2018

    Someone with a beaufitul heart could you send me the latest 300-101 dump?
    If you pass, you will be having a nice life with a lot of money in your bank account ;-)
    gambitec at hotmail dot com

  52. Anonymous
    January 15th, 2018

    Hi Guys, can you please send me a dump for ccnp route, email is spynx_21121 at yahoo dot com . Thank you in advance.

  53. bob
    January 16th, 2018

    Hi all, are the quizzes on the front page (flash quizzes) not the questions that are in the test?

  54. MOhamed Atef
    January 21st, 2018

    Could anyone send me last version of ccnp dump that still valid on my email : {email not allowed}

  55. MOhamed Atef
    January 21st, 2018

    Could anyone send me last version of ccnp dump that still valid on my email :
    mohamedatefm hotmail com

  56. MOhamed Atef
    January 21st, 2018

    Hello

    Could you send me last version of ccnp dump that still valid please

    the email : mohamedatefelgendy at gmail
    Kindly

  57. Mustt
    January 22nd, 2018

    Hello
    Could you send me last version of ccnp dump that still valid please
    the email : mustafa_basciftci at hotmail . com
    Kindly

Comment pages
1 2 1472
  1. No trackbacks yet.