pppoe query

I understand ppoe to be "ppp on ethernet".

Surely ppp is a packet/data handling protocol
and so is ethernet.
So isn,t pppoe overkill and an increase of overhead?

network ignorant but curious.

--
faeychild.

On Wed, 17 Dec 2003 09:15:10 GMT, faeychild <nykysle@ph> wrote:
>
>
>
> I understand ppoe to be "ppp on ethernet".
>
> Surely ppp is a packet/data handling protocol
> and so is ethernet.
> So isn,t pppoe overkill and an increase of overhead?
>
> network ignorant but curious.
>
> --
> faeychild.

Yeh, I think it is. But it's really handy because it can wrap the packets
from any protocol in its frames.

I do FTP and HTTP over ethernet....

Is that what PPOE is? Isn't it just a way to make a PPP connection beyond
the lan when that's what's being used on the lan? Just between your box
and the gateway?

Just guessing, actually. No reason it couldn't connect you to your ISP.

Interesting. One expert or another will set us straight here.

AC

faeychild <nykysle@ph@(E-Mail Removed)> wrote:

> I understand ppoe to be "ppp on ethernet".

> Surely ppp is a packet/data handling protocol
> and so is ethernet.
> So isn,t pppoe overkill and an increase of overhead?

Sure there is a small overhead running pppoe, but then it is just
a tunneling technology, easy to handle for ISPs which can assign
IP/etc just like with usual ppp connections.

> network ignorant but curious.

For more info, you might like to check RFC 2516, should be found
over there (www.faqs.org).

Good luck

--
Michael Heiming

Remove +SIGNS and www. if you expect an answer, sorry for
inconvenience, but I get tons of SPAM

Michael Heiming <michael+(E-Mail Removed)> wrote:
> faeychild <nykysle@ph@(E-Mail Removed)> wrote:

>> I understand ppoe to be "ppp on ethernet".

>> Surely ppp is a packet/data handling protocol
>> and so is ethernet.
>> So isn,t pppoe overkill and an increase of overhead?

> Sure there is a small overhead running pppoe, but then it is just
> a tunneling technology, easy to handle for ISPs which can assign
> IP/etc just like with usual ppp connections.

Exactly. Note the "Category: Informational" designation on the first
page of RFC 2516, and that RedBack Networks, Inc. was credited - that's
the company that promoted PPPoE in the beginning. It has no real value
for the consumer, but many advantages for the ISP, particularly in regard
to control.

Since the Standard Tracks DHCP protocol can assign IP addresses for
dialup ADSL, PPPoE is simply unnecessary and the RFC will always be
classified as Informational.

--
Clifford Kite Email: "echo xvgr_yvahk-(E-Mail Removed)|rot13"
PPP-Q&A links, downloads: http://ckite.no-ip.net/
/* Speak softly and carry a +6 two-handed sword. */

> It (pppoe) has no real value for the consumer

No real advantages ??? over what ??



If you dont use ethernet ( and hence PPPoE), then you need some other high
speed communications link between modems and hosts (PC's and
router/firewalls).


rs232 .. too slow
parallel port, too slow

synchronous serial, SCSI, USB,firewire-- too complex , expensive, cabling
issues


So PPPoE is the obvious common interface.

Leon. wrote:
>> It (pppoe) has no real value for the consumer
>
>
> No real advantages ??? over what ??
>
He's saying the using pppoe has no value for the consumer over just
sending raw ethernet over the phone companies ADSL line or the cable
companies cable. If they allowed us to just send raw ethernet, they
would have a very difficult time charging customers money for services.
They could only really charge for assinging ip address to clients, and
after that, they would have no real way of monitoring/controlling usage.
They would have no real way to tell if I were using enough bandwidth
to qualify as a business, for which they could charge more money. Using
pppoe puts the ISP business back into the realm of the circut switched
business model which they can more easily charge for. The phone/cable
compaines are outlandishly slow to accept change.

>
>
> If you dont use ethernet ( and hence PPPoE), then you need some other high
> speed communications link between modems and hosts (PC's and
> router/firewalls).
>
Ever used a LAN? its uses ethernet without the benefit of pppoe.
ADSL/broadband is perfectly capable of transmitting raw ethernet, just
as though you were on a local network that you set up at home. The only
reason the phone/cable companies dont set us up that way is because it
screws with their business/support models and they can figure out how to
cope.

>
> rs232 .. too slow
> parallel port, too slow
>
You're missing the point

> synchronous serial, SCSI, USB,firewire-- too complex , expensive, cabling
> issues
>
Still missing the point.

>
> So PPPoE is the obvious common interface.
>
>
How about oE without the ppp?


--
Neil Horman
Red Hat, Inc., http://people.redhat.com/nhorman
gpg keyid: 1024D / 0x92A74FA1, http://www.keyserver.net

Leon. <(E-Mail Removed)> wrote:

>> It (pppoe) has no real value for the consumer

> No real advantages ??? over what ??

After doing a google search for ADSL HOWTO I can see why you're confused.
This is a link to the ADSL HOWTO before PPPoE came along:

http://new.linuxnow.com/docs/content/ADSL/ADSL.html

It doesn't mention PPPoE at all; if you're not satisfied with Neil's
well-written reply then read it to see "over what."

--
Clifford Kite Email: "echo xvgr_yvahk-(E-Mail Removed)|rot13"
PPP-Q&A links, downloads: http://ckite.no-ip.net/

In article <(E-Mail Removed)>, Clifford Kite wrote:
> Michael Heiming <michael+(E-Mail Removed)> wrote:
>> faeychild <nykysle@ph@(E-Mail Removed)> wrote:
>
>>> I understand ppoe to be "ppp on ethernet".
>
>>> Surely ppp is a packet/data handling protocol
>>> and so is ethernet.
>>> So isn,t pppoe overkill and an increase of overhead?
>
>> Sure there is a small overhead running pppoe, but then it is just
>> a tunneling technology, easy to handle for ISPs which can assign
>> IP/etc just like with usual ppp connections.
>
> Exactly. Note the "Category: Informational" designation on the first
> page of RFC 2516, and that RedBack Networks, Inc. was credited - that's
> the company that promoted PPPoE in the beginning. It has no real value
> for the consumer, but many advantages for the ISP, particularly in regard
> to control.

There are advantages.

One advantage is multisession capability. I have my FTTH line at home
connected to two different ISPs simultaneously.

--
David Van Cleef - Engineering Manager
(E-Mail Removed) - Fusion Network Services, K.K.
(E-Mail Removed) - Global OnLine Japan
-- "We have forgotten at least two things..." --

David Van Cleef <(E-Mail Removed)> wrote:
> In article <(E-Mail Removed)>, Clifford Kite wrote:
>> page of RFC 2516, and that RedBack Networks, Inc. was credited - that's

>> the company that promoted PPPoE in the beginning. It has no real value
>> for the consumer, but many advantages for the ISP, particularly in regard
>> to control.

> There are advantages.

> One advantage is multisession capability. I have my FTTH line at home
> connected to two different ISPs simultaneously.

I take it that FTTH stands for Fiber To The Home. Can you give us a
URL that might explain what more precisely what "multisession" means
here and how it works? Or a brief explanation, including why you can't
do multisession FTTH without PPPoE?

Also you said "advantages" so how about another example?

--
Clifford Kite Email: "echo xvgr_yvahk-(E-Mail Removed)|rot13"
PPP-Q&A links, downloads: http://ckite.no-ip.net/
/* They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." Benjamin Franklin */

In article <(E-Mail Removed)>, Clifford Kite wrote:
> David Van Cleef <(E-Mail Removed)> wrote:
>> In article <(E-Mail Removed)>, Clifford Kite wrote:
>>> page of RFC 2516, and that RedBack Networks, Inc. was credited - that's
>
>>> the company that promoted PPPoE in the beginning. It has no real value
>>> for the consumer, but many advantages for the ISP, particularly in regard
>>> to control.
>
>> There are advantages.
>
>> One advantage is multisession capability. I have my FTTH line at home
>> connected to two different ISPs simultaneously.
>
> I take it that FTTH stands for Fiber To The Home.

Correct. In my case a 100mbps full duplex bidirectional line demarcated as
ppp over fast ethernet.

> Can you give us a
> URL that might explain what more precisely what "multisession" means
> here and how it works? Or a brief explanation, including why you can't
> do multisession FTTH without PPPoE?
>

Its fairly well described in RFC2516. The RFC makes explicit references to the
ability to set up multiple instances of PPPoE over the same medium to the same
or different PPPoE access concentrators. In a nutshell, after your first
session is set up, just go back to the PPPoE discovery phase and do it
again - start sending out PADI packets and set up another connection - the
protocol has had the fields in place to manage them from day 1.

In the common case here (Japan), the dominant telco (NTT) sells ADSL and FTTH
lines entirely independent of the ISPs (though they themselves operate several
ISPs using this equipment as well). The ISPs have IP-layer interconnects with
the telco, and the telco's PPPoE access concentrators will route the connection
to the appropriate ISP based on a RADIUS realm contained in the PPPoE username.

Typical lines (ADSL and consumer-FTTH) have capability of 2 sessions,
business-class FTTH lines can run up to 4 sessions. The typical situation is
that you maintain one session to your ISP, and a second session may be kept up
to connect with a VOIP carrier (QoS is supposedly handled differently) or to the
telco's own content sources (a limited amount of video-on-demand, etc.).

There's an extremely good guide at http://www.flets.com/pdf/flets-tech.pdf
(shows a much more detailed example of how PPPoE actually works than in the
RFCs) but its only in japanese.

> Also you said "advantages" so how about another example?

The ability at the LCP layer to transmit line quality reports (though I have
doubts that it is actually used that much in the real world).

--
David Van Cleef - Engineering Manager
(E-Mail Removed) - Fusion Network Services, K.K.
(E-Mail Removed) - Global OnLine Japan
-- "We have forgotten at least two things..." --