[LARTC] How to bond pppoe links

[LARTC] How to bond pppoe links

[Damjan]

I have three ADSL lines that I'd like to use as one big pipe to the
internet. The ADSL service works by establishing a pppoe connection (the
ADSL "modem" is a bridge), and each pppoe interface gets its own IP
address. 
This means I'd have to have 4 ethernet interfaces (3 for each
of the ADSL modems and 1 for the LAN) in my gateway. I'd setup the
gateway to NAT the LAN computers.

Now, I'm not completely sure how would this work, and what to expect.
Any suggestions from someone that has done this (or similar scenario)?



-- 
damjan | дамјан
This is my jabber ID --> damjan@bagra.net.mk <-- not my mail address!!!
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Re: [LARTC] How to bond pppoe links

[Rene Gallati]

Damjan wrote:
> I have three ADSL lines that I'd like to use as one big pipe to the
> internet. The ADSL service works by establishing a pppoe connection (the
> ADSL "modem" is a bridge), and each pppoe interface gets its own IP
> address. 
> This means I'd have to have 4 ethernet interfaces (3 for each
> of the ADSL modems and 1 for the LAN) in my gateway. I'd setup the
> gateway to NAT the LAN computers.
> 
> Now, I'm not completely sure how would this work, and what to expect.
> Any suggestions from someone that has done this (or similar scenario)?

Yes it is possible, though it may make only sense iff you have several 
clients behind the gateway (since for example http is a stateless 
protocol where most often every single picture and page is fetched using 
another tcp connection and if you balance it always, you are constantly 
switching the source ip which breaks ssl and session tracking. Generally 
you always use the same link for the same destination, which means less 
balancing, so you need more clients to even it out again)

But for help, I have found the nano-howto extremely useful.
http://www.ssi.bg/~ja/nano.txt


-- 

C U

      - -- ---- ----- -----/\/  René Gallati  \/\---- ----- --- -- -

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Re: [LARTC] How to bond pppoe links

[diab]

D> I have three ADSL lines that I'd like to use as one big pipe to the
D> internet. The ADSL service works by establishing a pppoe connection (the
D> ADSL "modem" is a bridge), and each pppoe interface gets its own IP
D> address. 
D> This means I'd have to have 4 ethernet interfaces (3 for each
D> of the ADSL modems and 1 for the LAN) in my gateway. I'd setup the
D> gateway to NAT the LAN computers.
It's only possible to "bond" the interfaces correctly (meaning that
eg. one ftp download could reach almost the sum speed of all ADSL
interfaces) if you have an other computer on the other end that
"splits" the packages for you.
I've managed to do it but keep in mind that it's only worth it if you
have a colocation facility near by where you do not pay after the
traffic.

It looks like this:

lan - gw === coloc - internet

between the GW (your gateway) and the coloc (the computer you have
total control over at a colocation facility) there are any arbitrary
number of transports (eg. ADSL lines).

the trick is to create one VPN connection over one ADSL line (I am
using vtund, ether tunnel over TCP because UDP didnt work for some
reason) and bond the tunXX intefaces together on both sides using
ifenslave. after this the default route should be set to bond0 and
if ip forwarding is enabled on the coloc machine it all miraculously
works.

vtund should be running as a server on the colocation machine and each
client instance on the lan gw should connect using a different ADSL
interface.
if can be achieved by running pppd with "nodefaultroute" and with the
combination of iptables MARK / ip rule / ip route different instances
(connecting to different ports on the coloc machine) of vtund client
connections will be routed on the correct interface using
packet classification and static routes.

we've been running an internet cafe on 2x1,5mbit ADSL here in
Hungary reliably on this link adding only 2-3ms delay (because of the
additional routing / extra computers) and having at least 90%
bandwidth of the 3mbit. the colocation computer is also set up at the
isp where we're getting the adsl from, so it's relatively "near" in
terms of latency.  it worked rather shitty (if at all) when one of the
lines was 512 and the other one was 1500.

i've also heard of isp's in England who support ethernet bonding so
you may just order a bunch of adsl lines and bond them together on
your end. there might be some in your area as well :) (definitely not
here in Hungary though)

--
diab




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Re: [LARTC] How to bond pppoe links

[Damjan]

> Yes it is possible, though it may make only sense iff you have several 
> clients behind the gateway (since for example http is a stateless 
> protocol where most often every single picture and page is fetched using 
> another tcp connection and if you balance it always, you are constantly 
> switching the source ip which breaks ssl and session tracking. Generally 
> you always use the same link for the same destination, which means less 
> balancing, so you need more clients to even it out again)
> 
> But for help, I have found the nano-howto extremely useful.
> http://www.ssi.bg/~ja/nano.txt

I think this will work... I've made some preliminary tests, a simple
multipath default route:
 ip route add default proto static  nexthop dev ppp0 nexthop dev ppp1
and I saw packets going out from both of the interfaces.

I've also tried to setup MLPPP on the PPPOE links but it seems that the
DSLAM on the other side didn't support this.

-- 
damjan | дамјан
This is my jabber ID --> damjan@bagra.net.mk <-- not my mail address!!!
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Re: [LARTC] How to bond pppoe links

[Rene Gallati]

Damjan wrote:
[..]
>>
>>But for help, I have found the nano-howto extremely useful.
>>http://www.ssi.bg/~ja/nano.txt
> 
> 
> I think this will work... I've made some preliminary tests, a simple
> multipath default route:
>  ip route add default proto static  nexthop dev ppp0 nexthop dev ppp1
> and I saw packets going out from both of the interfaces.
> 
> I've also tried to setup MLPPP on the PPPOE links but it seems that the
> DSLAM on the other side didn't support this.

If you want true bonding, you need someone on the other side of the 
links to "unbundle" for you. That means either your ISP(s) or you can 
also have a system on the internet and create a tunnel to that host over 
the links. It was described today under the subject "Packet Level Load 
Balance inbound/outbound success with nth and route".

If you are not going to get a cooperative partner on the other side of 
the links, the loadbalancing described in nano is about the best you can do.

Please note that you absolutely need some of the other lines if you have 
incoming traffic. Traffic might come in through one but leave by the 
other interface with the wrong IP address otherwise. This is not always 
bad and often works if all links go over the same ISP. I have one cable 
and one dsl line from two different providers. I had a bit assymetric 
routing until I corrected it.


-- 

C U

      - -- ---- ----- -----/\/  René Gallati  \/\---- ----- --- -- -

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