PPPoE in DSL modem/router (novice question)

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I use Verizon DSL (in my location Verizon uses PPPoE). My modem is a
Westell 6100 modem/router. ( I have no additional networking hardware.)
My OS is Fedora 7 (Linux).

I would like to have a clearer understanding of which PPP functions are
integrated in my modem.

When I used to use dial-up, PPPD ("PPP daemon") was running in Fedora.
Now, with DSL, PPPD is not invoked. Fedora includes PPPoE software (from
Roaring Penguin Software). But this software is not being invoked on my
system.

PPPoE is running on my modem/router. Does the modem/router also run PPP?
I've read that PPP consists of a number of major states: establishing,
authenticating, networking, terminating, and dead. Is any or all of this
functionality integrated into the modem/router?

Additional questions:

1. Is the ethernet cable between my NIC and modem carrying strictly
ethernet frames, as if the PC were on a LAN with no Internet connection?

2. Is the line between my modem and phone jack carrying PPPoEoA frames
or just PPPoE frames?

3. Is there an information source (e.g. website, article, book) that
elaborates on this? The PPPoE RFC is of minimal help to me. It just
illustrates how PPP frames are encapsulated in ethernet frames.

Re: PPPoE in DSL modem/router (novice question)
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Your question is really oddly worded. PPP over Ethernet is running in
my routers, does my router also run PPP? Since PPPoE is PPP over ethernet,
yes, its running PPP. Almost every router (as opposed to bridge or
"dumb modem") has PPP over Ethernet or over ATM or both built into.

It handles all phases and negotiation of the PPP protocol to talk back
to the ISP for you.

Yes, your workstation can also do PPPoE. So can every Windows and Mac box
out there. But they in general don't.


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Yes.


It really depends on what you mean and what your ISP does. Most do run
their DSL networks on ATM. I'm not sure by what you mean with PPPoEoA.
There's PPPoE and there's PPPoA. Technically both run over the ATM
network. Or PPPoE can also run over straight ethernet network, but PPPoA
can't.

Seperate protocols. The main difference is PPPoE has an extra 8 byte
overhead on each frame, so if PPPoA is supported all around, its
generally preferred as it doesn't have that.  PPPoE frames are still
going to be chopped up into ATM cells the same, so in general they are
the same protocol.

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Right, you keep posting questions and you're looking for the 10,000
foot picture with incredible detail, and people are telling you to
look at the source material to fill in the incredible detail.
There's not going to be a good source for you other than to keep posting.
Alot of what you are asking is just common experience in networking.


Re: PPPoE in DSL modem/router (novice question)
Doug McIntyre wrote:
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Thanks for your clear response. You answered my question, but I'd like
to explain my confusion. I'm a networking novice. My only source of
info on PPPoE is the RFC and wikipedia. Neither one of them describe
PPPoE as a superset of PPP which incorporates all of the PPP
functionality. They just describe it as the process of encapsulating PPP
    frames within ethernet frames. So to me, it was conceivable that the
PPP functions were being performed on the PC and PPPoE on the modem just
consisted of sticking those PPP frames into ethernet frames.
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I don't know what you're referring to. I don't recall anyone telling me
to look at source material for any of the networking questions I've
posted to various forums. I inquired about PPPoE in one forum, and I was
told to look at the RFC.  I gotta believe that between all of the
OReilly books, and the IEEE papers,and networking magazines, someone out
there gives a detailed description of the architecture of residential
gateways. Also, for dial-up modems, there used to be a number of
enthusiast websites. I haven't seen something similar for DSL modems.

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