Yes I can imagine using iptables to work but it was my understanding that this would only be able to determine the next hop and I couldn’t get it to force the decision higher up the chain. This would mean that every party along the chain has to play ball.

I can imagine that it would be beneficial for the internet experience if we could segregate low latency traffic (human/hft) traffic from hulk traffic such as video. Although this goes against net neutrality I suppose.

If you want it to be done externally without setting up a routing table then the next best option would be some kind of traffic tagging to indicate what you want to go over which line. That would start looking like a network with multiple VLAN:s.