Do you have to pay 2 sets of line rental to do that?
2 Sets of line rental, 2 broadband connections, A dedicated server or co-location with a 1Gbit/s uplink. Static IP's on both connections (Well that could probably be worked around, but it's easier in my case as I'm using GRE tunnels)
I'm still not even sure the routers I have will actually be able to handle it, I've managed 400Mbit/s raw GRE throughput through an ER-X when testing on the bench but that was without asking it to do PPPoE and firewall/nat on top. It wouldn't surprise me if I need to offload the PPPoE to another device.
I've managed to "bond" the connections using a L3 Multipath approach however the split has to be even (I.e 50/50 to each line) to do that.
It also helps at the moment that edgeOS isn't doing ECMP as far as I can tell (So it literally just puts packet1 line1 packet 2 line2.etc instead of doing it based on the flows). I'm not doing it at the moment as whilst it was successful in testing until the upgrade of my 2nd line to FTTC happens it would actually slow down my connection (Because the ADSL line is only 10Mbit/s).
In theory I think I could "bond" un-even lines using a slightly different approach but utilising the mangle feature of IPTABLES and nTH packet based marking, the problem with that alternate approach is it's really CPU heavy on the routers/firewalls which means I'm pretty sure the current kit I've got lacks the grunt to actually do it.
It's a lot easier to simply find an ISP that offers line bonding and pay them, it's just I already had a pulse8 ADSL connection as a backup for my FTTC line and also had a server in co-lo with sufficient (in theory) bandwidth to pull it off. That and It's one of those things that I thought I'd do to see if it works, more as a learning experience than anything else.
Whilst moving it to FTTC reduces the redundancy somewhat I figured hell why not i've always got 4G if the cab dies and now i'll actually use that circuit rather than pay for it and have it sitting Idle.
Anyone once the 2nd line gets upgraded to FTTC and I get the balancing/bonding working I'll post a speedtest result and we'll see if the routers can actually manage 120Mbit/s +