Talk:Point-to-Point Protocol over Ethernet

I have added Content from the German article to add to this one. The following points need clearing up:

• The first paragraphs of both articles are very different, and so I have left it alone - but that does not mean it could modified....

• There are no references, although I suppose the RFCs define it ( ? ) .

• The usual caps / technical terms issue.

Regards

ACH 17:00, 17 December 2005 (UTC)

IPCP and PPPoE and TCP/IP protocol stack

Where is IPCP located in the table provided? — Preceding unsigned comment added by 156.17.236.67 (talk) 07:50, 26 November 2011 (UTC)

"Reasons"

The article states that the reasons for using PPPoE is that Ethernet is connection-less and has no support for user authentication. However, it fails to explain why the network access server can't just use PHY information (like what actual telephone line the data is coming via) instead of adding an extra protocol layer. I haven't actually worked with a DSLAM, so I'm afraid I can't contribute this information myself. Dolda2000 18:19, 30 May 2007 (UTC)

Your question is probably more relevant at the PPP discussion page. I am assuming that you are asking why we need PPP at all when we can identify the individual links at the server. The basic reason is to hide the differences between the different kinds of physical links (async, serial, frame-relay, ISDN etc..) and their unreliability and provide a standard interface to IP. In fact one of the goals of IP itself was to hide the hardware differences and provide a single interface to any network application (like http). They just do this thing at every layer. For more details refer the PPP page. This article just specifies why it became necessary to run PPP over ethernet and why PPP originally did not run over it. Mukesh.mv 08:59, 4 July 2007 (UTC)

Actually, that isn't quite what I'm asking, because PPP has an obvious need over e.g. serial links, where there is no natural datagram boundary or standardized semantics for how to handle broadcast requests and such things. Ethernet, on the other hand, already has all those things that PPP is supposed to provide to links that don't have them. That's why I don't understand why anyone would want to use PPP over Ethernet. Dolda2000 18:34, 18 July 2007 (UTC)

Some answers -

* The DSLAM actually aggregates traffic from individual phone lines into one or two high performance links. Hence we cannot manitain user information that way.

* Ethernet does not have all the things that PPP provides. Ethernet is designed for broadcast mediums and is not a point-to-point protocol. Though it has a datagram boundary/multi protocol encapsulation etc., it lacks connection establishment, user authentication mechanisms. One way would have been to build this over ethernet itself. But since PPP already existed they just ran it over ethernet to solve the problem instead of inventing a new mechanism.

* Existing software at the server end would have to be changed if PPP was not used.

Hope this helps. Mukesh.mv 14:49, 5 August 2007 (UTC)

IP over ethernet is terriblly insecure! Anyone can send fake arp broadcasts or mac floods to spy on traffic! Anyone can take any IP address they like! There is no way to authenticate users. This is tolerable (though far from ideal) for an internal network in a company but totally unsuitable for a system where anyone can pay a small monthly fee and connect any equipment they like. PPP on the other hand establishes a well authenticated point to point link with strong authentication and if required encryption. Plugwash 00:03, 6 August 2007 (UTC)

Another possible reason might be that back when ADSL first appeared in the late 1990's, there were many legacy applications that still expected a dial-up line to the ISP. So back then there was greater need to provide a PPP interface to the user and PC. Also, reading some of the old documents from the time, it seems that one of the advantages being touted for putting PPP over Ethernet was that you then "dial up" on a PPP login client and access the Internet from any PC on the LAN, and even run multiple sessions simultaneously, on separate PCs, one per user. While this makes no sense in age when most people have all-in-one router+firewall+modem+WAP in one box, back in the early 2000s most ADSL setups did not include a router, and probably the best way to provide and control ADSL access was for each user have their own PPP login connection on the own PC to the ISP. 14.203.84.92 (talk) 08:42, 21 November 2016 (UTC)

The rationale for PPPoE has long eluded me and the given rationale still does not answer the obvious question -- or even mention it. Why not Ethernet over ATM, with a DHCP server/gateway at the DSLAM? Ethernet and DHCP were already ubiquitous at the time. This would require no new software or hardware (the modem excepted) at the customers' premises. Plug the cable into your DHCP enabled Ethernet port and "magic"; the connection just works. On the other side, the gateway at the DSLAM provides network isolation from other customer's traffic (no snooping, as suggested above). From the other side of the gateway, the traffic can be aggregated for transport. This is very close to what PPPoE does, but without the grotesqueness of grafting PPP onto Ethernet for transport.

For background, in the year 2000 I was the primary architect/implementer of the new BeOS network stack. I had already implemented PPP over asynchronous serial line at the time when I received notice that ISPs in some regions were deploying this new thing called PPPoE and in order to support these customers, I would have to implement it. I recall a fair amount of internal discussion, as no one on our small network team could fathom the impetus behind it.

After much discussion, research, and push-back against this new "requirement," our collective conclusion was that PPPoE was being deployed because ISPs were familiar with PPP and PPPoE fit neatly into their existing business model -- not for technical reasons. There was also a belief among ISPs that this "solution" would be be more familiar to customers, who had become acclimated to PPP over dial-up. Essentially, it was an argument of technological inertia -- sticking to what was familiar.

There is an argument above for multiple computers using separate "dial-up" PPPoE connections over a common Ethernet link. This still does not adequately explain it; DHCP can just as easily accommodate multiple clients over the same link, but with much less configuration hassle and protocol overhead. Again, this reinforces the idea that PPPoE was driven by familiarity with the dial-up model, rather than any technical rationale.

And 20 years later, I'm posting this over DSL connection still employing PPPoE and still looking for definitive answers. Jdinalt (talk) 21:25, 15 August 2020 (UTC)

Article title

Why is this article titled PPPoE, when every other protocol in the Internet protocol suite has its name spelled out? I propose that we move the page to Point-to-Point Protocol over Ethernet, to match the article for PPP. — EagleOne\^Talk 20:55, 18 December 2005 (UTC)

I agree - in the interest of consistency. One could just put a redirect at PPPoE. ACH 10:21, 19 December 2005 (UTC)

I posted a similar request on Talk:PPPoA today. If no one objects in a coulpe of days, I'll move the pages and fix the redirects. — EagleOne\^Talk 17:58, 20 December 2005 (UTC)

PPPoE and atm

ADSL is afaict atm based yet some providers use PPPoE rather than PPPoA or even allow both. How exactly does this fit in? Plugwash 01:45, 2 January 2006 (UTC)

"Fit in" in what sense? Yes, ADSL is ATM-based. Some providers run bridged Ethernet over ATM, and then run PPPoE over that. Some providers run PPPoA, and avoid using Ethernet at all. Some providers run bridged Ethernet over ATM and don't bother running PPPoE over that. Guy Harris 00:42, 28 October 2006 (UTC)

Reading the old Technical Report produced by the ADSL Forum back in 2001, it seems that they supported many combinations of existing protocols, from IP running directly over AAL5/ATM, or using PPP in between them helped by PPPoA or L2TP, or using Ethenet+L2TP, or both PPP and Ethernet. 14.203.84.92 (talk) 07:53, 21 November 2016 (UTC)

Password

How does the use of passwords in PPPoE links differ from the alternatives? Just what alternatives are used on DSLs where PPPoe is not? Jim.henderson 15:03, 25 October 2006 (UTC)

Some ADSL connections use bridged Ethernet over ATM without running PPPoE, and don't use passwords at all. Guy Harris 16:32, 25 October 2006 (UTC)

Correct...the article states Verizon FIOS connections are not using PPPoE. The article itself should also be edited to state that both Verizon FIOS and Verizon DSL services do NOT use PPPoE. I know this because I use regular Verizon DSL in both Florida and New Hampshire, and neither service uses PPPoE. SarasotaSlim (talk) 13:05, 6 June 2010 (UTC)

Ethernet is atm based and can use a variety of schemes for transmitting IP over that, including PPPoE (i don't entirely understand how this works, i guess it uses atms ethernet like emulation layer or something) PPPoA and a variety of older protocols. Both PPP variants handle passwords in the same way as any other PPP variant (e.g. pap or chap), most of the other schemes afaict don't do passwords at all.

Ethernet is not ATM-based. See the Ethernet article to see how Ethernet works.

To understand how PPPoE works, see the PPPoE article and the RFC for PPPoE. It doesn't use anything about ATM. (ATM's "Ethernet-like emulation layer" is "LAN Emulation" or "LANE". It emulates an Ethernet or Token Ring LAN over ATM.)

PPPoA doesn't involve Ethernet at all. That's what the "oA" prt of "PPPoA" indicates - it runs PPP directly over ATM without Ethernet being involved.

The standard scheme for transmitting IPv4 over Ethernet doesn't involve any protocols other than Ethernet, ARP, and IPv4 itself; see RFC 894. The standard scheme for transmitting IPv6 over Ethernet involves Ethernet, IPv6 itself, and assorted other protocols.

Bridged Ethernet over ATM doesn't involve PPP at all, and doesn't use passwords. See RFC 2684.

Well, thanks, everybody, especially the ones who remembered to sign their names. My problem with a relative's two years old Verizon DSL connection was fixed by calling the toll free help number and the guy in India talked me through putting the password in correct places, namely both the Actiontec router and a place in XP Networking. In my own Verizon DSL installed this summer (one computer under WinMe and one 98SE) there is no password. No security measures in the link, router, or computers that I can see. Whether either of these ADSLs have ATM or bridged Ethernet or both or neither, I have no idea.

Why someone at Verizon two years ago thought consumer DSL needed the security, verification, compression etc features of PPPoE, I may never know, but fortunately they changed their mind and no new users are afflicted with security that makes insecurity. Ought the article say whether PPPoE is rare or common, new or obsolete, in consumer DSL and CATV Internet? Jim.henderson 05:24, 28 October 2006 (UTC)

ADSL always has ATM. Whether it has bridged Ethernet over ATM without PPPoE, bridged Ethernet over ATM with PPPoE, PPPoA without any Ethernet, or whatever, is up to the provider. I've no idea what Verizon have done over time; the page at [1] suggests that "ADSL Data Network Release 1" might have used either bridged Ethernet over ATM without PPPoE ("IP over Ethernet over ATM") or bridged Ethernet over ATM with PPPoE ("PPPoE over ATM"), and that "ADSL Data Network Release 2" might have used either bridged Ethernet over ATM with PPPoE or PPPoA ("PPP over AAL5"). Perhaps there's a "Release 3" that went back to bridged Ethernet over ATM without PPPoE. (That document says "Bell Atlantic", which indicates how old it is. :-)) Guy Harris 07:01, 28 October 2006 (UTC)

Section for average user

Could a short section be added that gives the average user a simpler description? For example...

• Where does the average user set PPPoE? Must it be set on each computer in the local network?
• Why would PPPoE be necessary for DSL but (apparently) not for cable modems? Doesn't the Ethernet network itself (including router etc.) look the same in both cases? So why would the type of modem (DSL versus cable) make a difference?
• Regarding the statement "By using PPPoE, users can virtually "dial" from one machine to another over an Ethernet network", what does this typically look like to the user? Don't most modern operating systems already provide this?

This would help average readers better understand what PPPoE is actually used for.

3dimen (talk) 23:27, 20 June 2008 (UTC)

PPPoEoE vs PPPoEoA

I'm struggling to understand the difference here - the section 'How PPPoE fits in' seems to imply that they both run over ATM and both involve RFC2684 bridging. Can someone make this a bit clearer? Kisch (talk) 12:48, 4 August 2008 (UTC)

Basically, PPPoEoE takes the whole ethernet frame with its embedded PPPoE packet and encapsulates it into ATM frames on the other side, effectively bridging the ethernet network (i.e. making it appear that there's a virtual ethernet network extending from the client's site to the ISP's.) PPPoEoA, on the other hand, takes the embedded PPPoE packets out of the ethernet frames and encapsulates them in ATM, more of a relaying or forwarding process. -- Steved424 (talk) 09:23, 1 June 2009 (UTC)

Changed to PPPoE connection

My service provider had an outage of late. eventually after phoning a couple of times resetting my router to default etc. they told me to set up a PPPoE connection, now it works. On my mega105wr router my internet led does not come on, only the dsl led is on. My router in the web based management does not show it has a ip address or default gateway. Why is this. —Preceding unsigned comment added by Steggos (talk • contribs) 07:51, 8 October 2008 (UTC)

With PPPoE, your "router" is actually operating below the IP layer, merely forwarding PPPoE packets from the ISP to your PC. In this setup, it's your PC which runs PPP, and so gets an IP address assigned and needs a default route. Because of this, you should make sure you have a firewall running on your PC - such as the one that comes with (I think) XP SP2 and later. -- Steved424 (talk) 09:28, 1 June 2009 (UTC)

broadband connection

most users are basically intrested in the way computers are connected to intrenet. so i'va added a introduction with the help of a block diagram to create the intrest of newbie about the layers of protocol and devices involved in the connection to internet and thier importane.

regards --gursimar singh mohar 15:01, 26 December 2009 (UTC) —Preceding unsigned comment added by Simar mohar (talk • contribs)

Overhead

When the overhead for a 1492 byte payload is calculated as ${\frac {1500-1492}{1492}}={\frac {8}{1492}}$, I would expect to calculate the overload for a 60 byte payload as ${\frac {8}{60}}$ which results in 13.33 %. Therefore I doubt the mentioned 15.3 %. -- Simon04 (talk) 15:31, 27 February 2011 (UTC)

PPPoEoA vs PPPoA

The quirks section claims that PPPoEoA is different from PPPoA. I don't quite see the difference, especially since PPPoA can use either VC multiplexing or LLC encapsulation. Can someone clarify this ? The second diagram might have to be modified, or perhaps titled differently. Bomazi (talk) 21:42, 31 March 2011 (UTC) I heard you. I thoroughly reworked these two diagrams, expanding them and adding detail and context. I hope this work helps.CecilWard (talk) 23:37, 3 September 2012 (UTC)

PPPoE-speaking??

I was about to remove all instances of "speak" in the article where it was inappropriate, and replace them with more appropriate terms, because it sounds like a colloquialism. Surely, electronic equipment communicate with each other using protocols, not simply shout into the air like people do. Seeing as the use of this term is very pervasive in this article, I decided not to, because I'm not knowledgeable in PPPoE, and it's been known for colloquialisms to become normal technical language in computing circles (i.e. window, file, folder, mirror, etc). But if someone who knows a lot about PPPoE is reading this, and knows that "PPPoE-speaking" is not a technical term, please replace it with more appropriate terms. --BurritoBazooka (talk) 21:26, 28 January 2013 (UTC)

You are right - “become normal technical language in computing circles” is indeed the case here. The verb “speak” is like “she speaks French” which means that you can speak and can understand the language (not that you are speaking it just now). The things that can be understood or “spoken” are typically. protocols or headers, or possibly data formats. A real-world example: “A BGP-speaking” device is one which can understand or which does speak the BGP protocol. “Can and does understand” and “does participate” are the senses that are most important. An example of not being a something speakerSome nodes have info going through them, but they don’t and are not allowed to understand the format of it. It is required that the data remains just a block of bytes whose meaning is none of your business. This is one important case of being a non-protocol-X-speaker; the other is where protocol-X traffic does not reach some part of the network because it simply doesn’t get that far or because protocol conversion has happened earlier.CecilWard (talk) 13:14, 27 August 2014 (UTC)

DHCP to PPPoE

Why is Frontier DSL (bought out what was formerly Verizon DSL) switching to PPPoE from DHCP? The article makes it sound like DHCP is the future and PPPoE has nothing but extra unnecessary snags? I work for a company that has an ISP portion thru Frontier lines. I heard it was to monitor outages on the network easier, but I don't see how a drylooped phone line number is not easy to monitor for outages. --Lakecityransom (talk) 02:17, 8 May 2013 (UTC)

I've not seen any source saying that DHCP has obsoleted PPPoE (or IPCP to be more precise). Since it was basically unsourced speculation, I've deleted it. The GPON spec indeed does not provide for PPPoE configuration, however, ZTE, a manufacturer of GPON equipment, has seen fit to patent (in 2010) a certain use of PPPoE over/with GPON, and they argue in the patent that it's quite useful... Someone not using his real name (talk) 05:52, 11 December 2013 (UTC)

A bit of googling shows that a fair number of other ISPs use GPON with PPPoE, e.g. Orange France Globe Telecom [2]. Also other equipment mgfs. (besides ZTE) support PPPoE with GPON e.g. the Alcatel/Lucent 7342 ONT family, Huawei HG8245 ONT, Alphion AONT-1240 or the Tellabs 1100 OLT (google and you'll find a PDF brochure each of these). So I'm not buying that PPPoE is on its last legs. You wouldn't see all these manufacturers bothering with something that is patented (in some way) and not in the GPON standard if it made no practical sense. Someone not using his real name (talk) 06:34, 11 December 2013 (UTC)

Also there are various documents by the Broadband Forum which mandate (to the extent that their guidelines are taken seriously) that PPPoE must be implemented, even with new techs like EPON, e.g. TR-200 "Using EPON in the Context of TR-101" (2011) [3] says "The OLT and the multiple-subscriber ONU MUST be able to perform the PPPoE Intermediate Agent function, as specified in Section 3.9.2/TR-101." Someone not using his real name (talk) 06:43, 11 December 2013 (UTC)

Verizon

Also, Verizon has a page [4] "Am I on a DHCP or PPPoE network? Your location determines whether you are on a DHCP or PPPoE network. Select your state below to find out which network you are on." which suggests they don't even use the same method in all states (though probably some of that service is still DSL)... Someone not using his real name (talk) 08:42, 11 December 2013 (UTC)

Also, there's definitely FIOS in Maryland (I lived there) but if I select that state, the page says "PPPoE Based on your state selection, your Verizon High Speed Internet connection probably utilizes PPPoE (Point to Point Protocol over Ethernet)." LULZ. I'm deleting the claim that they switched to DHCP (everywhere). Someone not using his real name (talk) 08:45, 11 December 2013 (UTC)

ADSL Protocol Comparison

This is a good source for information - https://www.broadband-forum.org/technical/download/TR-043.pdf - comparing the various protocol stacks - in Section 3.2 and App B and C. 14.203.85.11 (talk) 05:14, 13 November 2016 (UTC)

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