Question: is there QoS support in MikroTik equipment for wireless links/access?
I use a queue tree with 8 queues set at limited speeds to achieve this on fixed wired links with a limited speed, and it
works fine by limiting just below the defined speed for the link. The proper queue is selected based on the high 3
bits of the DSCP.
On a wireless link, it is more difficult because there is no fixed speed. What I would expect, and how it actually works
on Ubiquiti equipment, is that there are multiple queues on or near the hardware radio level, and the packets are
put on those queues depending on the DSCP. The hardware then always sends packets from the highest priority
queue first, and then the lower ones. E.g. on the Ubiquiti equipment there are 4 such queues and they are selected
based on some fixed mapping of the DSCP values. Similar to what happens in switches.

In the MikroTIk documentation I find a reference to nv2-qos:
nv2-qos (default | frame-priority; Default: default) Sets the packet priority mechanism, firstly data from high priority queue is sent, then lower queue priority data until 0 queue priority is reached. When link is full with high priority queue data, lower priority data is not sent. Use it very carefully, setting works on AP

frame-priority - manual setting that can be tuned with Mangle rules.
default - default setting where small packets receive priority for best latency

This appears to be part of a similar solution, where I could make some mangle rules to determine the queue to use.
(which is also what I am doing with the queue tree on wired links)

However, the name nv2-qos suggests that this is only possible with the NV2 protocol. Is this true? Or does it also
work with the 802.11 standard? Is there a way to enable it on 802.11?

http://wiki.mikrotik.com/wiki/Manual:WMM

Ok, this is what I need and I already have the correct DSCP markings.
That article does not tell how to enable WMM.
Is it already on by default?