PPPoE load balancing

[lukek]

Hello,
Let me apologise firstly if this is a topic which has been thrashed to death
on this list.  I need some advice before I get myself into a hole that is
very deep, dark and lonely.

I need to add an additional DSL line to my exisiting network to keep up with
the expanding bandwidth requirements of the users. In a situation like this
my first reaction would be to get some fibre into the office and take it
from there but the building we are currently in is unsuitable for fibre (
according to the provider ) therefore for the interim I have no choice but
to get additional DSL circuits.

My question is how difficult is it to get one FBSD router to reliably manage
multiple DSL circuits. These circuits would have static IP addresses
probably /28 on the outside and there are two distinct networks internally.
An ethernet segment and a wireless segment.

I am using IPFilter and IPNat to provide simple NAT functions and simple
firewalling functions. If I create further external links ie tun0 and tun1
will this create problems for NAT ? I am contemplating separating the two
internal networks so that the ethernet segment gets routed to tun0 and
wireless to tun1. Would I need two instances of IPNat and IPFilter or can I
wrap all the rules into one instance of these tools ?

Is there a smarter way to do this ?

Any advice is appreciated as I suspect that this is not a trivial thing to
accomplish reliably and given no other real options at this time I have to
come up with a solution that is reliable. Ideally it would be great to be
able to get load balancing and failover working but I won't push my luck.

Regards,

LukeK