I don't know why but I did another test after upgrading two RB2011UAS to 6.3 using two 100FX SFPs (Digitus DN-81103 and DN-81104, LC, single fiber, 1310/1550nm) and crossconnected them.
I had to disable auto-negotiation and manually set the port-speed to 100Mbps.
I configured a test-network on both interfaces using IPs 192.168.66.1 and .2.

Running the integrated bandwidth test I get about >60Mbps bi-directional over tcp with standard settings (CPU is probably the bottleneck).

Can anyone else confirm that 100BX SFPs finally (!) work using ROS 6.3? And if I'm not dreaming right now, why isn't there a hint in the changelog?

And if I'm dreaming - don't wake me up!

Interestingly the LevelOne SFP-7321 (specs as Digitus DN-81103) is not working.

Can someone from Mikrotik confirm this?

Maybe I don't see the forest for the trees. Maybe I'm going crazy.

Working setup:
RB2011UAS-RM (6.3) + Digitus DL-81104 <-fiber-> RB2011UAS-IN (6.3) + Digitus DL-81103
I can do bandwidth test, ping the other side, etc.

Not working setups:
RB2011UAS-RM (6.3) + Digitus DL-81104 <-fiber-> RB2011UAS-IN (6.3) + LevelOne SFP-7321
RB2011UAS (6.3) + Digitus DL-81103/4 <-fiber-> LevelOne FVS-3800 media converter with adjacent Digitus DL-81103/4 <-RJ45-> LAN
RB2011UAS (6.3) + Digitus DL-81103 <-fiber-> FTTH fiber (same fiber and config works using media converter)

Converters and SFPs are a-ok and I tested them several times. I don't get why I can connect two RBs by fiber with 100FX, but can't connect to our LAN by fiber + converter, or can't connect by fiber to our carrier's test loop (looping back to our core router). I can live with the other SFP by LevelOne not working, but this whole situation right now gives me headaches

Does anyone have an idea?

I run some tests too.

ROS version: 6.28

Setup: RB2011 (SFP1) <---> Fiber <---> RB2011 (SFP1)

Speedtest with MT Bandwidth Test. UDP, everything standard, direction: both

Results:
1 GBit/s SFPs:
Cisco GLC-SX-MM (1GBit/s SPF) <--> Cisco GLC-SX-MM (1GBit/s SPF) - works with 100/910MBit/s (TX/RX)
Cisco GLC-BX-D <--> Cisco GLC-BX-U (1GBit/s SFP) - works with 120/930MBit/s (TX/RX)

100 MBit/s SFPs:
Cisco GLC-FE-100FX <--> Cisco GLC-FE-100FX - no link
Cisco GLC-FE-100FX <--> Cisco GLC-GE-100FX - no link
Cisco GLC-GE-100FX <--> Cisco GLC-GE-100FX - no link
HP ProCurve 100FX (J9054B) <--> HP ProCurve 100FX (J9054B) - Link, but no data transmission


My vote:
1Gbit/s SPFs work.
100MBit/s SFPs do not work.


Keep on dreaming

Can anyone find a custom sfp with 1.2G link to the board and 100mbps optics? I think that would surely work!