I have a RB951G-2HnD with the latest RouterOS v6.43.2 installed. When I connect it at port 2 (or another port, this is not a PoE issue) with a Netgear FVS318N LAN port using a straight or cross-over 8p cable, LED indicates link on both devices, but the connection doesn’t work. It works when I connect MikroTik to an Ubiquiti gigabit switch and then connect the Ubiquiti with the Netgear. It works when I connect MikroTik to the Netgear with a 4p cable forcing it to go down to 100 Mbps.
Is there a known incompatibility with other hardware at 1 Gbps?
The EIA / TIA-568B standard is only a 4-pair cable with 8 conductors. https://en.wikipedia.org/wiki/TIA/EIA-568
Wiring
See modular connector for numbering of the pins column in the table (1000BASE-T signal ID).
The problem is that MikroTik is unable to communicate with a Netgear using a standard 4-pair cable with 8 conductors. The same cable works for connection of PC-Netgear, PC-Ubiquiti or MikroTik-Ubiquiti, all at 1 Gbps. The 2-pair cable was used only for a test.
It is assumed that on all 5 ports of the RB951G-2HnD device the speed does not exceed 100 Mbit / s when using 4 pair cables?
The 2-pair cable can only operate in 10/100 Mbps mode.
Try to test the connected cable to one of the ports on the RB951G-2HD device connected to Ubiquiti.
Run (Winbox)—> Interfaces—> Duble click — ether(number of the port under test)—> Cable Test—>Start
If in the field the status value is displayed (link ok), then everything should be ok with the connection. If this field displays other information, then something is wrong with the connection.