Dropped packets in trunk interfaces


I having dropped packets in my two OpenWRT devices. This is what I have at home:

The red dots are VLAN 10 and yellow ones are VLAN 10. The connection between the RouterOS and OpenWRT devices is with a single wire with both VLAN in tagged.

In the remote TVBOX I have pixeled video sometimes and this is what I start looking for a solution.

In the RouterOS trunk interface there is no any dropped packets, but in the OpenWRT ones yes:

Is something I can do it for fix this drops? How could I debugg it better?

I am using 19.07.3 version in both OpenWRT devices.

I will really appreciate your help.

Best regards.

Those are dropped when received, right?.
You may have faulty cables causing errors to packet contents, or the router's CPU is too busy or something like that.

The amount is so small, less than 1/1000, that I wouldn't be too worried about it.

1 Like


Maybe you meant VLAN 10 and 100?

Which OpenWrt?

@hnyman brings up a very good point...because there are valid reasons for a packet to be dropped. I was going to hazard a guess for a few in the case of the OpenWrt-1 (mostly related to a movement of WiFi, IP, a cable or machine)...but realized something else...

Can you check the output for the actual VLAN also?

ifconifg eth0.10

1 Like


Thanks for the replies.

I change one of the OpenWRT AP for a gigabit one. Now both APs are MT7621 devices (Xiaomi Mi4A gigabit).

VLAN 10 is the LAN network, and the VLAN 30 is the VIDEO network that I see some pixeled images. Before I use the APs, I had netgear switches and there was not any pixeled image, so I can discard the wire problem (maybe the Xiaomi ethernet ports are less sensitive?)

In the eth0.10 there are dropped packest too:

I have dropped packets in both APs:

I have no way to see the dropped packets in the VLAN30 network.

When I had Netgear switch, I have IGMP Snooping activated, but now I think it is not necessary because it is only available to enable in the LAN (VLAN 10) network. The multicast streams goes in the VLAN 30:

The CPU is low in both APs:

Thanks again for your help, is there any configuration I can do to get less dropped packets?

Best regards.

Why are you unable...?

You simply run ifconifg eth0.30 like you did for VLAN 10?


The VLAN 30 has no interface in the APs:

It only has interface in the VLAN10:

Both APs use same switch hardware: (mt7530)

I see there is some pull request to this hardware: https://github.com/openwrt/openwrt/pull/2847

Hope this PR will help to fix the problems.

Kind regards.

Create VLAN 30 as well.


But I don't need the VLAN 30 interface in the APs, this VLAN is just for the TVBOX.

I have VLAN 10 interface because it is the home LAN network and I use this interface to manage the APs.



Latest release fix my dropped packets: New fixes feedback - Xiaomi Mi Router 4A Gigabit Edition (R4AG/R4A Gigabit)