strange behaviour I faced with.
Installing Multimode SFP S-85DLC05D with manual speed set 100M and Full-Duplex > other side CISCO SG350 with Mikrotik SFP S-85DLC05D. Works ok.
Installing Singlemode SFP S-31DLC20D with manual speed set 100M and Full-Duplex > other side CISCO SG350 with Mikrotik SFP S-31DLC20D. Does not work
Seems that the Multimode module implementation on speed selection (10 / 100 / 1000) is done and tested correctly or the SFP chipset has some limitation?!?!
I have only Mikrotik SFPs, so other brand's recommendation will not help.
1G connection speed works ok, but that's not the scope at this special case.
Cisco port shows activity LED and link ok, from WEB GUI as well (I guess that monitors the SFP and backplane comm itself and not the fibre link health).
At the same time checking from Mikrotik side ACT LED is off, no link observed, can't ping. (obviously)
I have latest OS 7.5 in CCR-1036-8G-2S+, and the test is done to prepare the 100M for a legacy Switch, but failed even with Mikrotik own module.
Is there a limitation with the Single mode module using in CCR-1036? I read that generally 100M SFP modules does not operates in SFP+ slots; which not the case.
The supported 1,25G SFP should operate on lower (and selectable speed) is SFP+ slot in my readings.
Did anybody meet this issue before?