i connect RB2011 and cisco3550 at gigabit port but port’s light on both device is off.
But if i set speed 100M and set full duplex on gigabit port both cisco3550 and RB2011 then port’s light is on.
But if i set speed 1000M and set full duplex on gigabit port both cisco3550 and RB2011 then port’s light is off.
i need to use speed 1000M at gigabit port not 100M.
Anyone can help me pls.
nobody can help me
I had the same constellation some time ago. Worked without a problem…
Why don’t you use auto on both sides?
KR,
uebi
How about configuring both sides to autonegotiation?
i want use speed 1000Mbps at gigabit port
so if i set autonegotiation i just can use speed 100Mbps which it not enough for me.
is it possible to use speed 1000Mbps between RB2011 and cisco3550
How long is this cable?
Does it run past lots of power?
If so, is it shielded?
Is the cable cat5 or cat6?
Try connecting to a PC with each of the troublesome devices to isolate the problem. Once you know if it’s the Cisco or the MT, then take it from there.
Does it support gigabit? I mean cisco3550
Depends…
WS-C3550-24-SMI is 24x 10/100 plus 2x GBIC (1000)
…
WS-C3550-12G is 10x GBIC (1000) plus 2x 10/100/1000 Copper
KR,
uebi
Chances are good that your cable is busted. 100mb requires 2 of the 4 pairs to be connected, gigabit however requires that all 4 pairs be connected.
you can use a cable-diagnostics on the Cisco to test the cable, or alternatively use a cable tester device
I believe the cisco 3550 does not support cable diagnostics.
More than likely the cable
Got a couple of 3750’s here, all of them supports it…
Well… The 3550 is a bit older than your 3750 
woops 
Hello:
My experience is the same: a Cat. 4500, module WS-X4424-GB-RJ45 and a RB 1100 AH X2.
Nothing to negotiate. The only way is cisco at 100 Mb. Full duplex, No auto.
Cable length is 2m.
Regards.
strange .. today I’ve got my brand new RB2011UAS-2HnD-IN and can not get gigabit ports working at gigabit speed with my computer (intel gigabit ethernet card) too … cable is cat5e, shilded … tried different cables/brands = still the same .. works fine on 100mbit… well.. it’s enough to run 100mbit/s with this router at present location for now but I still wonder what is wrong …
JF
I have a similar problem with port speed on the RB2011 - I have posted a thread here
I would be interested to hear if you made any progress.
I’ve been using router/switch equipment for 10+ years and this is the first instance of a port speed problem I can remember. The only difference is that this is the first Mikrotik I’ve used. Rather disappointing 
How about configuring both sides to autonegotiation?
\
I have similar problems with Cisco 7200 devices. On ports 1-10 is troublesome. On ports 11, 12 or 13 it works.
Just a note: the RB2011L Gbit/s ports running against the RB600A will not get me reliable operation even when set manually 100Mbit/s mode - after some time the port will lock up and no traffic will pass, only rebooting the units will fix it. Tried changing cables, but nothing changed. Now running that connection over the 100Mbit/s ports just fine with the same equipment.