I have a 802.11n link (RouterOS 5.0rc7, R52N, nv2, two chains - two cross-polarized antennas) which runs fine at 162-216 Mbps. But when the traffic is very low the wireless data rate falls dramatically (like 78-104 Mbps) - looks like if one chain is being disabled, because I disabled lower MCSes. The whole thing looks like some kind of power saving to me.
This is annoying for two reasons - the latency (ping time) increases and I can’t monitor link quality (I display data rates charts using mrtg/cacti to see how the link performs - and I don’t know if lower data rate is caused by interference or that ‘power saving’).
This is normal behaviour for 802.11n as it was written into the protocol for laptops that need to reduce power consumption.. as 802.11n cards do consume more power than 802.11abg cards so disabling one chain is permitted on low traffic levels. But not sure why Mikrotik needs to implement this “feature” if that’s what is happening?
RouterOS isn’t disabling any chains when there is no traffic. The only thing what is does it lowers the data-rate when there is no traffic. If you do not like it, you can disable the lower data rates, but note that you should have a good link to avoid disconnections as the wireless driver is lowering the data-rates when it can’t send the data to the other wireless node.
Is there any way to disable this data-rate lowering without disabling lower data rates? I need lower data rates exactly in case of link problems. And also as an indication of link problems - so if the data rate falls, the link still works and I know that something is going wrong.
After disabling lower data rates I’ll get disconnections - just as you wrote. Without disabling them - I get automatic data-rate lowering when there’s no traffic, so I don’t know if it is caused by interference or by low traffic. How to disable just this ‘automatic data-rate lowering’ feature?
You should see worse ccq values when data rate is lowered due to problems.
Driving with lower data rates at lower traffic should give a more stable connection
as there are more robust modulations used at lower data rates.