[Linux-ATM-General] R: R: Build up ADSL2+ Router with 2(!) PVC's

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> -----Messaggio originale-----
> Da: lin...@li... [mailto:linux-atm-
> gen...@li...] Per conto di Stefan Draheim
> 
> Am Dienstag, den 29.05.2007, 13:40 +0200 schrieb Giampaolo Tomassoni:
> > > -----Messaggio originale-----
> > > Da: lin...@li... [mailto:linux-
> atm-
> > > gen...@li...] Per conto di Stefan Draheim
> > >
> > >
> > > Hi all,
> > >
> > > ...omissis...
> >
> > Why the ATM-Card? You need a Linux-compatible USB ADSL+ modem.
> >
> > I'm actually using two Alcatel SpeedTouch 330 USB modems (but I
> believe they
> > are ADSL modems, not ADSL+) to connect to two upstream channels doing
> load
> > balancing on them.
> 
> I think I should have pointed out more clearly, that my ISP provides me
> with ONE physical circuit und uses TWO channels on this circuit. So I
> do
> need a configuration with somethink like two subinterfaces on one
> physical interface.

Well, I was talking about Virtual Circuits, not physical ones... :)

> And this is, where I see my biggest problem: I need
> a modem, where I can configure two channels on one physical port. As
> far as I can see, no buyable DSL-Modem is capable of this?

Every linux-compatible modem should work.

Since you are going to use pppoe for your links, you have to create two NAS
with br2684, then start two pppoe sessions over them.

The two NASes are created by invoking br2684 twice with two different values
for the -a switch (the one by which you specify the
[atm-interface.vpi.vci]). Say your ADSL modem will be the first one in the
system. It will get ATM device id '0'. Then, your two br2684 command to
issue will be something like:

	br2684 -c 0 .... -a 0.1.32
	br2684 -c 1 .... -a 0.1.35

Now you'll get the interface nas0 tied to the 1.32 (virtual!) channel over
the ATM device 0, and the nas1 tied to the 1.35 one over the very same
interface.

At this point you would probably need to "UP" the two NASes assigning an IP
address to them. The IP addresses you assign to the NASes are meant only to
get up the interfaces, since PPPoE should work by broadcasting packets.
Then, you may do something like:

	ifconfig nas0 inet 10.0.32.1 netmask 255.255.255.0 up

and

	ifconfig nas1 inet 10.0.35.1 netmask 255.255.255.0 up

Then you have to start two pppoe sessions over the two created NASes. Most
distros supply a pppoe plugin for pppd. Have a look at its configuration in
pppd. Somewhere in the conf you will have to specify the ethernet device
over which pppd have to run. Of course, this have to be one of the NASes. Le
say, in example, that you may need to invoke the following command:

	pppd noipdefault defaultroute user 'username@isp' noauth updetach
usepeerdns plugin rp-pppoe.so nas0

for the "Internet" virtual circuit, and the following:

	pppd noipdefault nodefaultroute user 'username1@isp' noauth updetach
nousepeerdns plugin rp-pppoe.so nas1

for the VoIP channel.

You will end having two ppp interfaces: ppp0 (the interface to Internet) and
ppp1 (the one to your ISP's VoIP server). Due to this, you have to be
careful with routes since you want your VoIP traffic not to go over ppp0 but
instead over ppp1. So, specify a route to the ISP's VoIP server such that it
injects the VoIP traffic over ppp1.

Please note I never used pppoe for my conns, so your mileage may vary. PPPoE
over DSL, however, is successfully used by many Linux users and there is
plenty of docs about it. The most common pppd plugin for pppoe is borrowed
by the rp-pppoe package. Google it.

> > The question is: which is the protocol your ISP requires on the
> Internet
> > circuit (1/32?). If the other circuit is dedicated to VoIP, you need
> > probably to run an IP stack over there, too. Or instead you need to
> use a
> > different technology there? In the first case, also for that you need
> to
> > know the protocol your ISP requires in order to connect. In the
> latter,
> > please tell us how you are requested to deliver voice over that
> circuit.
> 
> After some more information, this shouldn't be the the problem. My ISP
> requires on both Channels PPPoE, VoIP is done via SIP and RTP.
> 
> 
> > Actually, the Linux-ATM stack supports PPPoA, PPPoE, ClIP e IPoA. I
> never
> > had to setup a PPPoE or IPoA link, but probably their and surely the
> PPPoA
> > and ClIP implementations in Linux, do allow for defining multiple
> > connections on different VPI/VCI channels over the same interface.
> >
> >
> >
> > > So I hope someone here's able to help me a little bit:
> > > - Is it possible to build up what I think about?
> >
> > Probably yes.
> >
> >
> > > - What ATM-Card (or are there DSL-Modems available) is usable,
> where I
> > > can set up the required PVC-settings? (The modem will be directly
> > > connected to the DSLAM via the telephone line.)
> >
> > Again, you probably don't need it.
> >
> >
> > > - Do I have to care about ATM-VPI/VCI-setting as I can set them via
> > > br2684?
> >
> > So you have to use IPoA?
> 
> Ok, this was a missunderstandig from my side, I found too much pages,
> where this has been mentioned in combination with DSL. ;-)

If you were using IPoA (or even PPPoA) things where much simpler here. I
don't understand why a lot of ISPs run PPPoE, which complicates things,
wastes bandwidth and produces MTU issues...

Oh, by the way: I was a bit inexact in my previous post: both RFC2684 and
ClIP are IPoA protocols (the first is bridged IPoA, the latter is routed
IPoA).

Giampaolo

> 
> 
> >
> > For what I know, the br2684ctl utility in linux lets you attach
> different
> > ATM circuits to different network adapters, regardless of the per-
> interface
> > channels used. So, a probable reply to your question is no, you don't
> care.
> > Through ADLS USB Modems, ATM cells enter quite raw into the modem's
> driver.
> > Destination discrimination is done there in software, not in
> hardware.
> >
> >
> > Giampaolo
> >
> > > - Anything I didn't thought of till now?
> > >
> > > Hoping for your help.
> > >
> > >
> > >
> > > Regards,
> > > Stefan
> > >
> > >
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