I have problems with full duplex mode on switch TPLink TLSL2218, which connected to Mikrotik RB1100AH router (RouterOS ver. 6.39.1 stable). In web console of switch I discovered that ethernet port to router is working always in half duplex mode.
I checked a few times settings on Mikrotik router and TPLink switch. All RB1100AH ethernet ports have 100M and full duplex settings (auto negotiation is off, flow control is on, first five ports are in switch1 group - range from ether1 to ether5). All ports of switch have 100M, full duplex and flow control settings.
I tried to connect ethernet cable to other ports of switch (gigabyte and not gigabyte) - the same problem. Also I tried to connect cable to any ports of switch1 group - the same problem.
All other ports of switch is working on 100M full duplex mode correctly. To ports of Mikrotik swich1 is connecting a few servers, which working in full duplex mode without problems.
Please let me know where is my mistake. How can I check the real mode and speed between router and switch? Download a big file from any host via switch?
Thank you for your reply.
I enabled auto negotiation for 100M advertise only and it switched to full duplex. I read at wiki that “auto negotiation should not be disabled on one end only” and “gigabit link cannot work with auto-negotiation disabled”. I enabled autonegotiation and set 1000M advertise on mikrotik port and connected to gigabit port of TPLINK. After that connection is working correctly.
Is it possible that on switch auto negotiation option enable by default?
Thank you.
Do I need to set auto negotiation on user’s PC, which connected to the switch? I turn off this option on ethernet card manually, but speed 100M fullduplex.