Ethernet - link down

Hardware MikroTik hardware general
1

Hello,

I’m currently facing an intermittent issue with a link going down and then coming back up on the CCR2004-16G-2S+ RouterOS 7.11, affecting both the WAN and LAN ports and consequently impacting the service.

I’ve taken several steps to address the problem:

-Replaced the cables.
-Manually configured the interface speed to 1 Gbps after disabling auto-negotiation.
-Deactivated loop protection.
-Restarting the device.

Example of the recurring log entries appear as follows every few minutes:
22:16:44, interface, info ether1- link down.
22:16:47, interface, info ether1- link up (speed 1G, full duplex).

I’m actively working on resolving this issue to restore stable connectivity.
any help is appreciated

Thank you

2

7.11.1 changelog contains quite a few items mentioning bridge and stability in same sentence. Some mentioning bugs introduced in 7.10 or 7.11 …

Beware that 7.11.1 contains a bug in DHCP server, so you probably want to upgrade to 7.11.2.

3

Thank you, I upgraded tp OS 7.11.2, Hope the issue will be resolved

4

Unfortunately, after upgrading to OS 7.11.2, the issue still exists.

5

I also had my ether 1 port going up and down recently on a CCR1036.
I too changed cables without success.

I have not found the solution yet, but for the time being, I migrated to another eth port that was available to get my system running.

6

If I’m the case is only ether1 then im ok can change the port, but its happening in all used ports! The issue wasn’t happening on os 6.49 only happens with os 7
I hope mikrotik do something about it

7

Such things are hard to replicate. So ideally you would create a supout.rif file while any of ports are down and another one soon after the flapping port gets up again. Then open a support ticket and provide both files to MT. That would give them chance to figure out what’s happening.

8

Thank you, I have upload the support.rif to Mikrotik support hope they reply me

9

Here is a screenshot, can anybody help me?

10

Category 6 cables? If yes, try changing to cat5

11

I already tried to change the cables, and this issue is not happening with our router running Os 6.49 only the router with Os 7
which I suspect is software or hardware issue

12

downgrade 7.8

13

Thank you for your suggestion, I done downgrade but the issue still happen

14

Downgrade the version until the problem goes away

15

I downgraded until 7.4.1 which is the factory firmware and still happen!!!

16

I installed a Switch between WAN and Mikrotik and noticed it worked without the port dropping!
Like in the photo below
any idea why?

17

I have many towers where i get link flapping.
Some of them happen every day, others - randomly.
Many just don’t flap at all.

The switches i use are CRS326

Not i have 2 main places where it happens a lot:
CRS326 + LHG60
There are other LHG60’s in the same spot and only one would drop the link. Cable has been replaced, no change.

CRS326+UBNT PowerBeam AC5 Gen2

It randomly switches to 1gbit, than drops to 100mbps a hundred times a day.
After some time it will stop flapping and works ok, than next day it starts again.
SNR in the ubnt antenna is 30 at all pairs..

I use the same shielded cable for the links.

UPD:
And now when i disabled auto negotiation,
interface status says 100mbps full duplex, but in the powerbeam it says 100mbps half duplex. Which one to trust?

FW versions are latest for today (CRS326 was 6.47 until today, but nothing changed after upgrade both FW+Bootloader)

18

You should trust both sides … because without auto negotiation each side uses whatever it’s set to do. In your case you have a duplex-mismatch which can (and will) disrupt traffic occasionally (more if link is loaded higher). So by all means change settings so that they match on both sides. I’d go with full duplex unless you encounter some problems.

19

hello, I encountered the same problem as you, you image link is down, could you please re-upload it again, how to put the switch, this problem has haunted me for so long.

20

Are you using shielded cables?