Hi all there,

i am new to this forum and first write something about me:
It is nice to read here and everytime i use Mikrotik devices!
I do this for many years and working since round about 20 years as IT-Admin.
With Mikrotik i do switching, routing and wireless, CCR, CSS, LHG (5/60) SXT, RBs, hap, wap, and so on, i use nearly everything.
A small local wisp in Germany only with Mikrotik and Datacenter services with colocation again only with Mikrotik.

My problem:
A PTP link between two SXTsq5ac around 1km distance, nearly free line of sight with NV2 and AC only 40Mhz channel bandwith.
The link is working stable at -68db to -72db (35db to 38db signal to noise) for months now.
Bandwith is ok (around 120mbps TCP in both directions) latency is also ok...
The wireless connection does not disconnect over days / weeks.
-> A stable link in my eyes.
But if there is no traffic, the ip connectivity broke (ping does not work, winbox cannot connect etc. no IP traffic possible)
A MAC Ping over this connection is always working, the connection itself does not drop, theres nothing in the Log.
But if there is a little traffic, like a open winbox (around 55kbps) the ip connection is working all day long.
Some pings in parallel are not enough.

It is always like 10 seconds IP working, 30 seconds not, 10, 30....... (but MAC Ping is working all the time around 2-4ms)

I updatet to 6.44, tried another frequency, use nstreame, disabled NV2 security, everytime the same...
There is no firewall or something activated which may block the traffic, routing is ok.

Has someone a idea?
It is not a good solution for me to leave a winbox permanently open at a Server (like it is now!) to create a little Traffic.


Also i have a probelm with latency if there was heavy traffic.
Without big traffic the latency over this connection is about 2-4ms.
If there is heavy traffic (120mbit) the latency drops to 40-50ms this is ok.
But if the traffic stops, the latency is jumping between 10 and 40ms (without traffic!)
If i do a reconnect, the latency is nice again.
After a (re)connect it is syncronised to 60-120mbit (MCS9-11) if needet by traffic the modulation is going up to MCS12 (180mbit) but it stuck there also if it is not needet.
I want to turn down the modulation again if it is not needet by traffic, is this possible?