DSL that also uses dial-up (PPPOE)

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Why do some DSL services use pppoe, which is like using both dialup and
ethernet, whereas some DSL services seem to just use ethernet?

Doesn't this affect whether or not DSL connects automatically at
startup?

I think SBC DSL uses pppoe.


Re: DSL that also uses dial-up (PPPOE)


Hi Richard,

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You seem to have made an association that is not really
there........;-)  PPP is not JUST dialup, it is a protocol for
authenticating WHO the user is at the other end of a connection, and
it sets that connection up to carry IP type traffic. The connection
can be any one of Dial-up, DSL, Cable or whatever form of WAN
connection you are using. You can even use PPP over a Frame-Relay link
or over an ISDN service if you wish, and you can even 'stack" these to
create a larger "pipe" using what is known as "Multi-Link PPP".

Some things to think about -
  1. PPP stands for "Point-to-Point" Protocol. As such, it is only a
SESSION management protocol and it MUST be used over some form of
carrier service, be it Dial-up, DSl, Cable, Etc... It replaced what
started life as SLIP (Serial Line Internet Protocol), however SLIP had
limitations that do not exist in PPP.
  2. PPP over Dial-up Modem is the simplest form of PPP service
commonly used today.
  3. PPPoA (PPP over ATM) is a PPP link over a DSL service. DSL uses
ATM technology (Asynchronous Transfer Mode) as its carrier service.
  4. PPPoE is an PPP session over an Ethernet Service, however to do
this you first need an Ethernet service in place. You could use PPP on
an Ethernet link if you wish, however a more common form is to
configure a DSL service to provide Ethernet type connectivity, and
then use PPP for Authentication. The 2 most common forms of PPPoE are
PPPoE over a Cable environment, or PPPoEoA, which is PPPoE over DSL
  5. In addition, it is possible to configure a DSL service to deliver
pure Ethernet style connectivity, without PPP, however then the ISP
then has to work out how the end user is to be Authenticated and
managed, and this can pose some problems for them.
  6. Lastly, just to be really confusing, in some places a provider
may choose to deliver a DSL connection using ISDN services, rather
than ATM technology, however these are limited to 128Kbps and are
fairly rare and specific to longer run cable distances.

A key thing to remember is that some of the current terminology has
been adapted from pre-existing installations, and often you find some
DSL service provisioned using PPPoE instead of PPPoA, but the end
result is very similar.

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Nope,  it has nothing to do with it at all. What is important though
is to understand the ISO Protocol Layers being used, and to  
understand where things fit in.  A very rough analogy is -
  1. ISO layer 1 is the copper cable that goes into your house. it is
the PHYSICAL MEDIUM used to deliver the service.
  2. ISO layer 2 is the FRAMING or signalling on that cable (layer 1),
and it could be either V90 Dial-up Modem, Cable, or DSL (as examples).
  3. ISO layer 3 is the PPP session itself. This is the layer that
provides a method to authenticate WHO is at the end of the cable, and
once successful it provides the base level TCP/IP transport layer that
is required to get internet data between YOUR place and your ISP..
  4. ISO layers 4 - 7 are the traffic handling layers that the
software on your PC uses.

It is also critical to understand that for any layer to be able to
work, you MUST have the layer immediately below it in place first.

This is a very quick intro into all this but I hope it helps.

Cheers...........pk.


--
Peter from Auckland.

Re: DSL that also uses dial-up (PPPOE)



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Actually it's just a protocol for encapsulating packets. Some of
those packets might be for authentication but that's entirely
optional.

Personally I find the use of PPP over ethernet to be just plain
stupid. Ethernet already has encasulation and doesn't need
more overhead stacked on top of it.

--
http://yosemitecampsites.com /

Re: DSL that also uses dial-up (PPPOE)



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It gives them more control.

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It means you have to establish a pppoe session and, most likely,
login.

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They do. But there are some customers without it.

--
http://yosemitephotos.net /


Re: DSL that also uses dial-up (PPPOE)



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'at's what radius is all about (g).


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login _is_ ppp.  running it over ethernet is just a twist.


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And if they make _any_ changes (even circuit change) to their account they
will have to go to pppoe.



Re: DSL that also uses dial-up (PPPOE)



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No, it isn't.



Re: DSL that also uses dial-up (PPPOE)


Richard Fangnail wrote:
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Most all use PPPoE or similar. When you see the "just use ethernet" they
very most likely have given you a modem router and the router is handing
you an IP via DHCP.

Re: DSL that also uses dial-up (PPPOE)



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Mine doesn't.


Re: DSL that also uses dial-up (PPPOE)



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They use PPPoE, which is not dialup.  It uses PPP for authentication
and to encapsulate the traffic.

I can't say why some telcos use PPPoE - the reason probably
varies between telcos.  One advantage is that PPPoE gives them
more flexibility.

In an ethernet circuit, the gateway router has to be on the same
LAN segment.  Either the ISP has to provide each user with a private
LAN segment, using 4 IP addresses, or it shares a LAN segment with
several users and they see each other's broadcasts, ARP requests,
etc.  Use of PPP avoids this limitation, since it allows multiple
PPP links, each with a private segment, sharing use of a gateway
that forwards packets to the internet.

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My DSL (using PPPoE) connects automatically at startup.  Where is
the problem?


Re: DSL that also uses dial-up (PPPOE)


Neil W Rickert schrieb:
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Interestingly DSL here in Germany is provided by the T-Com (the has been
monopolist) but there are several Internet Providers on top of this.

So I can choos my provider by just changing pppoe login. And even more
interestingly it is even possible to connect to more than one provider
over ONE DSL line at the same time!

Wolfgang

Re: DSL that also uses dial-up (PPPOE)


On 26 Dec 2006 15:01:05 -0800, "Richard Fangnail"

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Lets them stack more customers per IP.

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