Equal cost multipath and shaping

I have two S.HDSL lines at 2Mbps each. I would like to bundle them to one line. I am currently simulating the two lines in a lab setup with two RB600’s.

If I just set the ethernet interfaces to 10Mbps and bundle them, I can get (almost) 2x10Mbps if I start two downloads. It works perfectly. However, if I add:

/queue tree
add burst-limit=0 burst-threshold=0 burst-time=0s disabled=no limit-at=0 max-limit=2048000 name=eth1 packet-mark=low parent=ether1 priority=8 queue=default
add burst-limit=0 burst-threshold=0 burst-time=0s disabled=no limit-at=0 max-limit=2048000 name=eth2 packet-mark=low parent=ether2 priority=8 queue=default
/ip firewall mangle
add action=mark-packet chain=forward comment=“” disabled=no new-packet-mark=low out-interface=ether1 passthrough=yes
add action=mark-packet chain=forward comment=“” disabled=no new-packet-mark=low out-interface=ether2 passthrough=yes

then all the flows share 2Mbps, no matter how many flows I add to how many different servers. (I have just one client; if there is reason to believe that it will work better with more clients, I can try that.)

What am I doing wrong?

Obviously this was a case where “debugging by maximising potential embarassment” was the right answer.

I am stupid, I AM actually getting 2x2Mbps – right now I have two flows at 1Mbps and 1 flow at 2Mbps (with a little variation.)

RouterOS works brilliantly as always.