Packet loss on Cambium 4625 (AP-SM)

The scheme has an active Wireless Link and also installed a backup Wireless Link Cambium 4625 SM - 2 pc (AP-SM):

When working on the main Wireless Link, everything works properly:

When switching traffic to the Cambium 4625 Wireless Link, we observe packet loss via icmp.

Wireless status and test:


In Monitor - Performance - Ethernet Statistics no Packet Errors and Packet Drops.

Settings for Cambium 4625 AP and Cambium 4625 SM (in AP channel bamdwidth 80 MHz):


Traffic 300 – 400 Mbit/sec. The air is pure. According to the internal wireless test, the results are higher than the speed of the transmitted traffic.

What could be the problem? Why are we seeing losses?

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This appears to be a PtP link, is there a reason you’re not using ePTP mode or TDD mode (if you need sync)? ePTP is the recommended mode for PtP links and provides the highest performance.

Why do you have your modulation rate set to DS MCS 9 instead of auto rate?

Is there any reason you’re using Winbox’s traceroute tool instead of the ping tool for measurements? Does it make a difference if you try the ping tool?

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Switched to EPTP mode. There is less packet loss. The interesting thing is that there are no losses in Mikrotik ping tool, but there are losses in traceroute tool.

There are no packet losses through the main wireless link in both the ping tool and the traceroute tool.

Why does this happen on the wireless link Cambium 4625?

I don’t know why those two test provide different results… but I’d be most concerned if actual traffic going across the link was being dropped. Are there issues with real world traffic passing over this link?

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I have the same exact issue with the same configuration and circumstances
I’m not satisfied at all with this model and i have tried every thing possible including downgrading / upgrading
Cambium support and engineers should seek a solution to this disaster because this packet drop thing is affecting any kind of service passing through this model