Is there a way to do a “set priority” on bridged traffic without having to set the global “use IP firewall” flag for all bridges
and then having all bridge traffic pass through the IP firewall, where in fact only a single MANGLE rule is desired?
Use case: to have WMM working on an access point that is in bridge mode. Transmitted traffic has to be classified
according to DSCP e.g. using “set priority” “from DSCP high 3 bits” but this can only be done when IP firewall is
active on all bridge traffic.
Maybe a special mode for this should be available on the Wireless interfaces, just like there are special cases to
set the TCP MSS on a PPP interface without using the corresponding MANGLE rule?
I can’t really say that I know much about this, but there’s also action=set-priority in bridge filters and this suggests that it’s the same thing as in IP firewall. The difference is that in IP firewall, there are two more options (from-dscp, from-dscp-high-3-bits), but I guess they could also be added to bridge filters?
Yes that would already be a solution, for this particular issue.
I’m not sure if it would be as efficient as a special case like was made for the TCP MSS adjustment, and why that case was done the way it is.
(I normally put a MANGLE rule for TCP MSS adjustment in the forward table in routers where tunneling is done, but apparently MikroTik saw
the need to do this in a special way in the common case of PPPoE. in earlier software setting the “adjust MSS” option in fact introduced a
dynamic rule in the MANGLE table, but now this is no longer done or at least no longer visible, and I think it is done somewhere in the driver
code for that type of pseudo-interface)
The thing is that in the competitor’s product, WMM is enabled and effective without any user configuration at all.
The DSCP value is fully automatically used to create 4 different queues for different traffic classes as described in the WMM spec.
In MikroTik products, none of that is happening. WMM has to be manually enabled at the Wireless interface, and even that does nothing
to do the prioritization. One still has to add the MANGLE rule. And in case the Wireless device is in Bridge mode (they often are…)
it is not very simple as then the option for “use IP firewall” has to be enabled on bridges (it is a global option for all bridges, well that is
not really a problem in this use case) and you have to be careful that the filtering rules are compatible with that, because enabling IP
firewall only for MANGLE is not possible.
Result: this is often not done or forgotten, and the performance of MikroTik devices in wireless networks that transport different
classes of traffic at the same time (e.g. downloading files and making VoIP calls) is quite poor.
Setting it up correctly makes a huge difference! But it is not a matter of one or two or even 20 clicks. It should be.