Bridge / TCP Performance

Bridge / TCP Performance

The following problem exists with with ROS5 / RB800 and transparent wireless bridges:

Using Tools → Bandwith Test we see 100 Mbit with UDP, but only 35 Mbit with TCP

Here is the network diagram

RB800 (1)
ether1
bridge1
vpls1
wlan
5GHzN,
NV2 or 802.11, CCQ 100%, Bandwith 300 Mbit,
wlan
vpls
bridge
RB800 (2)
ether1 connected to Gigabit Port on Foundry BI8000
connected to 100 Mbit Switch
connected to GBit Fiber 50km
connected to RX4 (several 10Gbit)
routed to RB1100AHx2 (3)

Bandwith Test with TCP
BT from 1 to 2 gives 100+ Mbit (230 Mbit UDP)
BT from 2 to 3 gives 95 Mbit
BT from 1 to 3 gives ONLY 35 Mbit (where UDP would be 95)
Also, downloads of any system connected directly at (2) gives 90+Mbit download speed
where downloads from system connected to (1) gives ONLY 25 Mbit download speed

I have been thru all kind of different setups (e.g. EOIP insted of VPLS, different MTU) with no improvement.
I use Mikrotik since more than 10 years, with lots of different scenarios and about 40 links.

By reading other articles in the forum, it is perfectly clear that bridgeing via WLAN is the problem
and does NOT (anymore) deliver acceptable throughput.

Is there any solution ?