Hello,
i have a x86 routeros 6.36.2 router with 3 ethernet interfases.
ether1 = wan 100mbps full duplex, no negotiation
ether2 = lan autonegotiation
ether3 = lan2 autonegotiation
so ether1 sometimes behave as 100hd on the status tab (also verified with some speed tests) even with the original setup on the ethernet tab.
so my current fix for this is to disable and enable this interfase and it changes (on status tab) to 10fd,
i do the same once again and it changes from 10fd to 100fd.
why is this happening.
sometimes it takes many hours to occur but other times it takes only a few minutes to repeat again.
This means you have a bad cable or interference problems due to very strong RF fields.
(e.g. we had this problem on our local 10M FM amateur radio repeater outputting 80W RF and the ethernet cables running
very close to the antenna system. in our case it was cured by putting some ferrite clamps on the network cabling, the wellknown
grey plastic clamps with tubular black ferrite cores in them that you find packed with some digital equipment and that
nobody bothers to put on the cabling because they do not see the need)
hello pe1chl,
thanks for your reply,
it does make sense for me so i will have a look at my cabling here and let you know by tomorrow.
really appreciated.
PD: if no ferrite clamps available, how much far should the data cabling be apart from the energy cabling?
the energy cabling is regular inhouse cable inside a plastic pipe. I used to run both the energy (inside the pipe) and data (outside the pipe) cablings together being confident my data cable is cat6 SFTP for indoor/outdoor use but now i have moved appart my data cabling to another path at many feets far awar from the energy cabling. Right now there are only 2 points where the cabinlgs cross each other at a few inches appart. I am having the same issues so far so i will test with a longer cable using another isolated path in order to see if this solve the problem or to know if i am having other kind of issue.
Also please note that i am using poe on my data cabling (24v x 1.2a = ~27w each data cable for runnings about 15 meters). Does this matter?
Thanks again
The ferrite clamp example was only to illustrate that RF energy could cause problems similar to what you see.
Unless your installation is at a transmitter site as well, there is little reason to believe that the cause is the same.
Those clamps did a very good job in our setup, but it may well be that they do nothing in your case.
This depends on the kind of interference (mainly its frequency).
On running cables parallel to AC energy cabling, the opinions differ. I would avoid running cables parallel
without any form of shielding. In practice, however, it appears to have little effect when doing only short
runs (a few meters). Long runs like cable ducts typically have separate compartments for energy and data
cabling, with a metal shield between them.
PoE use of the same cable should be no problem when the proper inserters and supplies are used, that are
putting only regulated DC on the cable and should not cause crosstalk to the data pairs.
When in doubt, always run a temporary cable from A to B (just roll out a cable over the floor) and see if the
symptoms are the same. When not, you can try to find what is the cause: the cable itself (bad crimp of a
connector, broken lead), or its path.
afther runing a isolated cabling from A to B using an alternative path i did realized that in the outside of facilities there was another run of energy cabling runing together with the data cabling so i did separate also this part of the runs and now the problem is gone
i was about to hit my head on the walls but now i am safe lol
Thank you so much.
