I have an issue with several RB3011 boards.
Some ethernet ports are often flapping. For example, they go from 1 Gbps to 100 Mbps negotiation, or they disconnect unexpectedly for short times (1 -3 seconds).
Of course this behaviour is causing lot of problems (I see frequent OSPF flapping between routers).
On the eth stats I often see some FCS errors.
I already checked my cat5e cables and plugs with Fluke.
The interesting thing I noticed is that the disconnections seem to be present on all ports of the same switch chip at the same time.
Please look at the following example, where you can see that eth6-eth10 flapped at the same time (they are connected to different devices but share the same switch chip internally)::
I tried with different RouterOS, now I use 6.42.10 (longterm).
Thanks for any suggestion,