- Mikrotik RB5009UPr with RouterOS 7.19.4
- L2 Switch only
- Asus RT-AX86U running only as an AP
Simplified schema:
Smartphone <---> AP <---> RB5009UPr <---> switch <---> PC
Due to some sluggish SMB transfers, I'm running some Iperf3 tests from a wired PC to a wireless Android, and the results are kind of odd.
The PC is on VLAN 7 (mgm), and the wireless devices are on VLAN 9.
When I run the test in normal mode with the Android as the server, I see a very low speed of about 3Mbps and many retransmissions.
$ iperf3 -b 0 --dont-fragment -P 2 -c 192.168.9.57
Connecting to host 192.168.9.57, port 5201
[ 5] local 192.168.7.3 port 37010 connected to 192.168.9.57 port 5201
[ 7] local 192.168.7.3 port 37024 connected to 192.168.9.57 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 512 KBytes 4.19 Mbits/sec 147 4.24 KBytes
[ 7] 0.00-1.00 sec 384 KBytes 3.14 Mbits/sec 141 4.24 KBytes
[SUM] 0.00-1.00 sec 896 KBytes 7.33 Mbits/sec 288
- - - - - - - - - - - - - - - - - - - - - - - - -
[ 5] 1.00-2.00 sec 384 KBytes 3.15 Mbits/sec 135 4.24 KBytes
[ 7] 1.00-2.00 sec 512 KBytes 4.19 Mbits/sec 131 1.41 KBytes
[SUM] 1.00-2.00 sec 896 KBytes 7.34 Mbits/sec 266
- - - - - - - - - - - - - - - - - - - - - - - - -
[ 5] 2.00-3.00 sec 256 KBytes 2.10 Mbits/sec 81 2.83 KBytes
[ 7] 2.00-3.00 sec 256 KBytes 2.10 Mbits/sec 75 2.83 KBytes
[SUM] 2.00-3.00 sec 512 KBytes 4.19 Mbits/sec 156
- - - - - - - - - - - - - - - - - - - - - - - - -
[ 5] 3.00-4.00 sec 256 KBytes 2.10 Mbits/sec 29 1.41 KBytes
[ 7] 3.00-4.00 sec 128 KBytes 1.05 Mbits/sec 28 2.83 KBytes
[SUM] 3.00-4.00 sec 384 KBytes 3.15 Mbits/sec 57
- - - - - - - - - - - - - - - - - - - - - - - - -
(...)
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 2.38 MBytes 1.99 Mbits/sec 550 sender
[ 5] 0.00-10.04 sec 2.33 MBytes 1.95 Mbits/sec receiver
[ 7] 0.00-10.00 sec 2.38 MBytes 1.99 Mbits/sec 535 sender
[ 7] 0.00-10.04 sec 2.34 MBytes 1.96 Mbits/sec receiver
[SUM] 0.00-10.00 sec 4.75 MBytes 3.98 Mbits/sec 1085 sender
[SUM] 0.00-10.04 sec 4.67 MBytes 3.90 Mbits/sec
However, when I reverse the flow so that the smartphone sends the data, the speed is more adequate for the wireless connection.
$ iperf3 -b 0 -R --dont-fragment -P 2 -c 192.168.9.57
Connecting to host 192.168.9.57, port 5201
Reverse mode, remote host 192.168.9.57 is sending
[ 5] local 192.168.7.3 port 47662 connected to 192.168.9.57 port 5201
[ 7] local 192.168.7.3 port 47674 connected to 192.168.9.57 port 5201
[ ID] Interval Transfer Bitrate
[ 5] 0.00-1.00 sec 33.6 MBytes 282 Mbits/sec
[ 7] 0.00-1.00 sec 33.8 MBytes 283 Mbits/sec
[SUM] 0.00-1.00 sec 67.4 MBytes 565 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
(...)
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.04 sec 549 MBytes 458 Mbits/sec 372 sender
[ 5] 0.00-10.00 sec 543 MBytes 455 Mbits/sec receiver
[ 7] 0.00-10.04 sec 459 MBytes 383 Mbits/sec 518 sender
[ 7] 0.00-10.00 sec 453 MBytes 380 Mbits/sec receiver
[SUM] 0.00-10.04 sec 1008 MBytes 842 Mbits/sec 890 sender
[SUM] 0.00-10.00 sec 996 MBytes 835 Mbits/sec receiver
When I run the same test from the PC to another wired PC on the same VLAN, the transfer reaches the maximum interface bandwidth. The same occurs when testing from an Android client to another Android on the same wireless VLAN 9.
In these cases, I think VLAN 7 should be contained within the switch, and VLAN 9 should be contained within the AP, not going through the Mikrotik router.
Running the test to external (Internet) Iperf3 servers shows the expected results, reaching my ISP's bandwidth limit. Also, there's no active VPN or firewall on the Android devices.
So, it seems to me that the router may be somehow limiting the local flow when routing between VLANs, but I cannot figure out what it is.
Here's mostly my current configuration.
20251008_conf.rsc (20.3 KB)
Please, any thoughts about this?