AX86u getting 200mbps on iperf3

[Gentoo]

Hi all,

I'm using an AX86u with the latest Asus firmware, and otherwise default settings and I seem to get only 200 mbps on iPerf3.

I used my iPhone 11 (5 ghz AX wifi client) to my 2.5gbps enabled desktop and I only got about 200 mbps on uplink. I expected far higher speeds.

Additionally, speedtests on my gigabit connection only show about 200 mbps - worse than my AC Asus router. When I look at the dashboard, it shows my iPhone connecting at only 1200 with only 1 stream. Why isn't it using both streams?

Any advice would be appreciated!!

 

[L&LD]

Does it have two antennae/two streams?

Did you enable QoS at all (even if it's disabled now)?

'Latest Asus Firmware' is less than helpful. Be specific, please.

 

[Gentoo]

Does it have two antennae/two streams?

Did you enable QoS at all (even if it's disabled now)?

'Latest Asus Firmware' is less than helpful. Be specific, please.

Hi.

I tried with QoS on and off.

Firmware Version: 3.0.0.4.384_9318

Wasn't sure if you meant the iPhone or router, but in both cases yes there are two streams.

Deployment Reference for iPhone and iPad

This content has moved.

support.apple.com

ASUS RT-AX86U AX5700 Wi-Fi Router Review

2.5Gbe hits mainstream platforms with the RT-AX86U AX5700 Wi-Fi router from ASUS. Join us as we test and see what it's all about.

www.tweaktown.com

 

[L&LD]

Seems you're getting the maximum possible on your iPhone (connection-wise).

What model do you have specifically? Seems only the 'max' models have the best specs.

Why are you using default settings? See if setting it to 160MHz helps.

 

[Gentoo]

Seems you're getting the maximum possible on your iPhone (connection-wise).

What model do you have specifically? Seems only the 'max' models have the best specs.

Why are you using default settings? See if setting it to 160MHz helps.

I have the base iPhone 11. However I've seen others on YouTube get 600-700 mbps on iperf and speedtests.
The document makes it seem like 80mhz is the max for the iPhone. I've just tried 80mhz and 160mhz with no real difference to the iperf tests. Still getting ~200 mbps to my desktop.

I reverted everything to default for the sake of debugging the problem.

 

[Gentoo]

Should I flash to Merlin or is the hardware defective?

Edit: Flashed to Merlin, yet still getting ~200 mbps on iPerf3 on LAN and speedtests even with 80 MHz bandwidth and locked to AX.

 

[L&LD]

Try these suggestions on RMerlin 386.1 Beta 2 to get the router to a good/known state before giving up on the hardware.

New M&M 2020

Fully Reset Router and Network

 

[Gentoo]

Try these suggestions on RMerlin 386.1 Beta 2 to get the router to a good/known state before giving up on the hardware.

New M&M 2020

Fully Reset Router and Network

Thanks for your reply, but I think I'll have to send this router back. Just can't get good speeds out of it even after trying the above. My older 68u is doing a better job!

 

[Kudzu]

Given that your username is Gentoo and that you are using the 2.5Gbps port, maybe you are seeing something similar to what I've experienced. Bottom line: I get great wireless throughput with the RT-AX86u, just not when using > 1Gbps NICs in a linux host. This is really inconvenient for me because my 10Gbps linux machine is my server and I want to be able to use it for both wired and wireless clients. Currently, wired performance is great but wireless client performance sucks.

Any machine + O/S combo, connected to the RT-AX86u (via 802.11ax or 802.11ac) sending and receiving to a linux host with a 10Gbps NIC is limited to around 300 to 500 Mbps. Take linux out of the mix -- i.e win10 to win10, ios to win10, ios to freebsd, ios to win10 -- and throughput is fantastic with this router, getting anywhere from 650Mbps to 950Mbs over wireless!! The really strange bit is that if I switch the linux host to a 1Gbps NIC, then wireless throughput is great (just like the other O/S) with this linux host. I'm still investigating this weird phenomenon but I've seen a fair number of fast TCP retransmits when linux is sending to a wireless host via 10gbps. I'm pretty sure its not wireless packet drops, and therefore not the rt-ax86u, because I dont see the retransmit when sending with other O/S or if using a 1Gbit nic on the linux host.

More details, observations, and oddities:

• Using iperf3, latest version on all O/S complied from srcs
• slow linux/10gb wireless max throughput doesn't improve w/ parallel iperf streams
• Fully wired 10gbs performance is always fantastic, regardless of O/S. Wired-to-wired will saturate 10Gbps with no retransmits, xmit failures, cksum failures, etc.
• There is a 10gb microtik switch in the middle of all this
• RT-AX86u is in access point mode
• Using 160Mhz channel. I'm the only one of my near neighbors using 5ghz, apparently. Lucky me.
• When testing, only one wireless client is associated with the router
• RT-AX86u connected to microtik switch using 2.5gbps port.
• Tried the latest official 384 FW as well as the recently released official 386 FW (as of 12/30 I believe)
• Tried ubuntu 18.04 and just now upgraded to 20.04 w/ its 5.x kernel to see if that helped
• Tried various tcp/ip tuning params such as frto, ecn, ts, congestion alg ( I normally use the default cubic everywhere as it gives good 10gbps performance)
• 10gbps NIC is a mellanox ConnectX-3
• I tried setting the number of transmit and receive rings of the mellanox to 1 each. Hypothesis was that since fast TCP retransmits can be caused by duplicate acks and duplicate acks can be caused by out of order receipt then perhaps there was a flow hashing problem in the melanox driver that produced out of order segments. No luck.
• If I run iperf3 on the asus router itself, I cant get over 1.25 Gbps wired performance via the 2.5 Gbps port
  • Parallel streams don't improve result
  • There are no TX/RCV errors on either side of the wired link
  • No TCP retransmits
  • When receiving, it appears router is cpu bound
  • Sending looks to be cpu bound on router w/ 384 FW, but now with 386 FW, sending barely touches cpu. Its still limited to 1.25Gbps, however.
  • Verified that link was negotiated at 2.5Gbps on both sides. Again, no drops so the link looks clean.
  • So is 1.25 Gbps going to be the upper limit on this router? I wonder if this is just a misconfiguration of the switch chipset somehow.
• Interestingly, switching the router's lan connection from 2.5Gbps to a normal LAN port reduces wireless throughput even though the throughput is less than 1Gbps to start with.

Sorry for the long post. My new iphone 12 mini sends 700Mbps and receives 950Mbs with this router so I've witnessed what's possible. Everything else should be tunable so I'm a little obsessed with maximizing my wireless performance right now. I might try acquiring a different NIC card to see if I can rule out the NIC/driver.

 

[kapekohicafe]

@Gentoo did you return your ax86u? i wonder if you got a new one and did a test already? any difference?