Hi, attached is my issue.

This is a brand new 433L routerboard, Connected to an 433uah

Both are running 5.20 with fw 2.41

Any Ideas?

bad cable? bad connector?

Connected to what?

"You are seeing visions, it is not happening."
Frankly you do not have any other option than to by a new set of equipments, because MT is not (active nor willing) to take that issue seriously.
http://forum.mikrotik.com/viewtopic.php?f=2&t=54038

"You are seeing visions, it is not happening."
Frankly you do not have any other option than to by a new set of equipments, because MT is not (active nor willing) to take that issue seriously.
http://forum.mikrotik.com/viewtopic.php?f=2&t=54038

We have not seen this issue once in our testing lab. All who have contacted support with their specific problems, have solved them. They were caused by malfunctioning device, bad cable or bad port. There is no software issue, as software can't cause port flapping. In older versions you simply did not see this, because ethernet logging was not implemented.

Put a switch between the devices and see which still portflap, if any. If you still see portflap on one device also change that cable. That way, its easier to see what device, cable, port or what ever is causing flapping.

"You are seeing visions, it is not happening."
Frankly you do not have any other option than to by a new set of equipments, because MT is not (active nor willing) to take that issue seriously.
http://forum.mikrotik.com/viewtopic.php?f=2&t=54038

We have not seen this issue once in our testing lab. All who have contacted support with their specific problems, have solved them. They were caused by malfunctioning device, bad cable or bad port. There is no software issue, as software can't cause port flapping. In older versions you simply did not see this, because ethernet logging was not implemented.

Normis do you think you could publicly Write on the forums about the past issues like a bit more detail of a few examples
i have been waiting a long time to see results of what the common problems are..

I personally took an assumption it was the capacitors..

please do tell, as you can see others have no clue so if you explain some situations it will help them.... makes sense right? and it will give you some credibility the next time someone gets very upset with this flapping problem that seems a little common.

thank you looking forward to your reply

I had this problem with an groove connected to rb750gl. Cable was ~10m, ftp, grounded, new. I have tried everything, upgrade ros, upgrade firmware, more upgrades to new an old versions, poe, etc. After I've changed the cable it worked. Try to change the cable maybe it helps.

To those who say software can't create port flapping, let me describe what I just did.

RB433L, ROS 5.22, two ethernet ports are connected. One is connected to a switch which goes to my office LAN. The
other port is connected with a 1 foot jumper cable to a Single Board Computer located next to the RB433L.

The above has worked well for over a year. I have never observed port flapping. The log correctly shows ports
that go up and down only when I unplug them on purpose.

At the request of Mikrotik support, while working on a multicast problem, I upgraded to 6.0rc6. (They wanted me to try 6.0rc7, but I have to wait for them to send it to me since it's not publicly available.)

As soon as I rebooted with 6.0rc6, both ethernet ports started flapping simultaneously about every 30 seconds. I made no changes to the hardware connections. I didn't touch or move the hardware or cables in any way. All I did was upgrade ROS using my laptop on another desk.

After observing the flapping for awhile, I downgraded to ROS 5.22 and the flapping stopped.

This would seem to indicate that software can cause this problem.

I had a ethernet port flap recently which was caused by rouge DHCP server on a customers LAN, enabled dhcp alert & mac + ip of this server is now listed in the logs?

http://wiki.mikrotik.com/wiki/Manual:IP ... ver#Alerts


http://forum.mikrotik.com/viewtopic.php?f=7&t=68954

I had such flaps from a CB radio transmitter nearby (ok, on my desk...) with a less than perfect matched antenna. So take also radio interference in account! In such cases FTP/STP cables could help.

Yes, CB radios and other transmitters could definitely cause flapping. However, in my case, the device has worked perfectly for a year and only flaps when running ROS 6.0rc6. A year of ROS 5.22 showed no problems and after downgrading back to ROS 5.22 there are no problems.

Flapping is caused by ROS 6.0rc6.

Perhaps there is something in the software that is more sensitive to issues that might cause flapping that was ignored in ROS 5.22, but that still is a software issue.

I can only confirm this.
Never seen it on 5.22 (the radio was there long before). I've seen it first on 6.0rc6. Maybe 5.22 didn't log those events?
And strangely, only port 1 on my RB450G was flapping (the one with PoE circuitry). Port 3 connected with an identical cable to the same switch was not (i separated IPv4 from IPv6 for those who are wondering...).
Switching cables kept the flap on port 1. EMC design issues?

It occurred to me also that perhaps 5.22 didn't log these events. I observe that 5.22 does log "ethernet link up" and "ethernet link down" events when I unplug the cat5 cable.

Just to be sure, I added the "interface" topic to systems->logging on 5.22. I still see no flapping on 5.22.