Mixed 1Gb + 100 Mb connection on RB4011iGS+RM drops down the performance of 1Gb link

Hardware MikroTik hardware general
1

On the device RB4011iGS+RM there is a serious HW problem when on the switch chip (port 1-5 or 6-10) are both 1Gb and 100Mb connection. When the traffic is only on 1Gb line, the throughput of this connection is about 1000 Mbps. When there is also 100Mbps traffic on 100Mb line, the traffic on 1Gb line drops down to only 100Mpbs. So only 100Mbps + 100Mbps.

When the 100Mb line is switched to 1Gb the performance is expected 1000Mbps + 1000Mbps.

It’s more serious than I thought. With the second line speed as 10Mb, the 1Gb interface maximum speed goes down to 10Mbps.

ROS 6.48.4

Same switch chip RTL8367 is used also in RB1100AHx4.

Can someone confirm this HW issue?

Gigabit ethernet port becomes fast ethernet port
Gigabit ethernet port becomes fast ethernet port
2

Common issue in mikrotik router without buffer on the ethernet ports

https://en.wikipedia.org/wiki/Micro-bursting_(networking)

3

I also see this problem on 960 boards. Wondering if there is any fix. The ports arent even in a switch, they are all routed.

4

RTL8367 has 1Mbit embedded SRAM for buffer.

5

See Block diagram in Support & Download

6

If you are using it as a switch disable HW acceleration on the 100Mbit/s port.

7

Where?

8

@engycz did you find a solution for this? I got the same problem with my hAP ac.

9

I have got email response from Mikrotik support. Not tested.
1)
Yes, it is a known issue because of the buffer processing between 10M-1Gbps interfaces. On other devices, such a problem will be corrected with a cpu-flow-control feature. Unfortunately, RB4011 does not have such feature support, but we are planning to implement it in one of the further RouterOS releases. RouterOS version 7 should perform better if your setup allows operating with development versions.
2)
Most likely cpu-flow-control feature will be added in RouterOS version 7. As a workaround you can update RouterOS to version7 and use the hw-offload feature, in such case the device should perform much better.

10

I have other thing.
If to any of port was plugged 1GB and to other 100MB. 100MB port will down in ~30min-1 hour. and need unplug and plug.
Different devices plugged. tried different cables.
tried move 1GB to 1-5 ports, 100MB to 6-10. not help
upgraded to 7.4 - not helped
Activated/deactivated HW - not helped