Assume the following setup:
4 WAN links (ether1, ether2, ether3).
6 local VLANs (vlan1, vlan2, …) on sfp1
Several of the VLANs map 1:1 with a WAN link, ie each VLAN gets a routing mark sending their traffic out a particular WAN interface. I want to attach a queue tree to limit upload / download to avoid buffer bloat and prioritize traffic, this is easy under this setup since I apply the upload queue to ether1 and the download queue to vlan1 for example.
The problem starts when I need to apply the same queue to VLANs that share a WAN link, in the above example, vlan2 and vlan3 both get routed out of ether2. In this case I can limit the upload by adding the queue to ether2, but if I add a download queue I cannot find a way to tell RouterOS that it should be a shared queue for both vlan2 and vlan3. If I add the same queue to both then the WAN link is easily saturated if clients on both vlan2 and vlan3 perform simultaneous downloads, and it also isn’t acceptable to halve the WAN bandwidth for each VLAN since when it’s idle clients on either VLAN should be able to utilize the full throughput. I can’t use the global queue parents since this would also affect the other unrelated VLANs.
Is there a way to do a multiple-interface queue tree or am I simply stuck here?