2 TM-AC1900, connecting AP to main router causes download speed to drop?

[ColinTaylor]

Just checking... Is your WAN Connection Type set to Automatic IP or is it PPPoE?

In your iperf test earlier what was the device running the server at 192.168.29.126 and is it Ethernet connected to the main router together with the client?

 

[pierop]

Just checking... Is your WAN Connection Type set to Automatic IP or is it PPPoE?

In your iperf test earlier what was the device running the server at 192.168.29.126 and is it Ethernet connected to the main router together with the client?

WAN Connection Type is set to Automatic IP.
on the iperf test, the server was my Desktop PC (192.168.29.126), connected to the main router.
the client was my laptop, also connected to the main router.
When this test ran, there were 0 wifi devices connected as the SSIDs were never used, and the PC and Laptop were connected wired.

 

[ColinTaylor]

I'm just wondering why you weren't seeing full gigabit throughput from iperf when both devices were plugged directly into the same switch.

C:\Utils\iperf-3.1.3>iperf3 -c nuc
Connecting to host nuc, port 5201
[  4] local 192.168.1.49 port 55372 connected to 192.168.1.10 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.01   sec   114 MBytes   941 Mbits/sec
[  4]   1.01-2.01   sec   113 MBytes   949 Mbits/sec
[  4]   2.01-3.00   sec   111 MBytes   946 Mbits/sec
[  4]   3.00-4.00   sec   113 MBytes   949 Mbits/sec
[  4]   4.00-5.00   sec   113 MBytes   950 Mbits/sec
[  4]   5.00-6.00   sec   113 MBytes   949 Mbits/sec
[  4]   6.00-7.00   sec   113 MBytes   949 Mbits/sec
[  4]   7.00-8.00   sec   113 MBytes   949 Mbits/sec
[  4]   8.00-9.00   sec   112 MBytes   944 Mbits/sec
[  4]   9.00-10.00  sec   113 MBytes   946 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec  1.10 GBytes   947 Mbits/sec                  sender
[  4]   0.00-10.00  sec  1.10 GBytes   947 Mbits/sec                  receiver

iperf Done.

 

[pierop]

I'm just wondering why you weren't seeing full gigabit throughput from iperf when both devices were plugged directly into the same switch.

C:\Utils\iperf-3.1.3>iperf3 -c nuc
Connecting to host nuc, port 5201
[  4] local 192.168.1.49 port 55372 connected to 192.168.1.10 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.01   sec   114 MBytes   941 Mbits/sec
[  4]   1.01-2.01   sec   113 MBytes   949 Mbits/sec
[  4]   2.01-3.00   sec   111 MBytes   946 Mbits/sec
[  4]   3.00-4.00   sec   113 MBytes   949 Mbits/sec
[  4]   4.00-5.00   sec   113 MBytes   950 Mbits/sec
[  4]   5.00-6.00   sec   113 MBytes   949 Mbits/sec
[  4]   6.00-7.00   sec   113 MBytes   949 Mbits/sec
[  4]   7.00-8.00   sec   113 MBytes   949 Mbits/sec
[  4]   8.00-9.00   sec   112 MBytes   944 Mbits/sec
[  4]   9.00-10.00  sec   113 MBytes   946 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec  1.10 GBytes   947 Mbits/sec                  sender
[  4]   0.00-10.00  sec  1.10 GBytes   947 Mbits/sec                  receiver

iperf Done.

Tested again, this is with everything plugged in, wired and wireless.
PC and laptop wired to main router.

PC ethernet adapter is: Realtek PCIe GbE Family Controller
Laptop ethernet adapter is : Intel(R) 82579LM Gigabit Network Connection

 

[ColinTaylor]

Well that's better than before so I wonder what changed. Did you have other devices connected when you did the first test. It might be useful to re-test with all devices disconnected apart from the two PC's to see if you can get a consistent throughput. If you still don't it could be an issue with one or other PC. I've seen problems like this caused by things like anti-virus software, third party firewalls, Windows updates, etc.

 

[pierop]

What changed between tests was that I had all my WIFI devices connected in the last test vs none during first test.
I'm still confused as to why connecting all the WIFI devices slows down my wired connection.

Can't test again at the moment, but I'll update when I do.

 

[Ronald Schwerer]

Not sure what features are included in the TM-AC1900 firmware. Maybe Airtime Fairness in the Professional settings(both 2.4 and 5GHz)? I may of missed it in a quick scan of this thread. Is all the QoS stuff disabled?

 

[pierop]

Not sure what features are included in the TM-AC1900 firmware. Maybe Airtime Fairness in the Professional settings(both 2.4 and 5GHz)? I may of missed it in a quick scan of this thread. Is all the QoS stuff disabled?

Yes. QoS is disabled.
Airtime fairness was already enabled for 2.4 and 5.0.

 

[ColinTaylor]

Airtime Fairness and Universal Beamforming are often suggested to be turned off for WiFi compatibility issues. However your problem doesn't appear to be about WiFi stability.

 

[Ronald Schwerer]

Airtime fairness was already enabled for 2.4 and 5.0.

I'd try it disabled. Not sure if it affects wired. Worth a shot.

 

[pierop]

Disabled Airtime Fairness and Universal Beamforming on 2.4 and 5.0 on all routers.

No change.

 

[Ronald Schwerer]

I hate to suggest more disruption, but some of these settings aren't effective without a reboot or a services restart

 

[pierop]

I hate to suggest more disruption, but some of these settings aren't effective without a reboot or a services restart

Yes I have rebooted both routers after every change.

 

[doczenith1]

Seems like we have two issues. The first being the drop in WAN download speed and the second being lower than expected LAN speed. For the WAN speed it seems that others have given some good ideas to try. One thing I didn't see mentioned was cpu usage. Have you looked at the router cpu usage both during 500 and 300 events? I believe NAT acceleration must be on if your getting 500 Mbps but worth double checking.

Edit: Was just re-reading through the posts and saw in one of your screenshots that NAT acceleration is enabled.

 

[pierop]

Have you looked at the router cpu usage both during 500 and 300 events?

not sure if I get what you're asking, while running the speed tests, CPU 1 is >90% while CPU 2 stays below 10%.

 

[ColinTaylor]

not sure if I get what you're asking, while running the speed tests, CPU 1 is >90% while CPU 2 stays below 10%.

If you don't have full (Level 2) NAT acceleration enabled your download speed may become CPU limited. It looks like this might be the case. With full NAT acceleration the CPU load should be almost zero (when testing from an Ethernet attached device).

In your screen shot in post #7 your NAT acceleration was set to Level 1 CTF. Can you change this to Level 2?

 

[pierop]

If you don't have full (Level 2) NAT acceleration enabled your download speed may become CPU limited. It looks like this might be the case. With full NAT acceleration the CPU load should be almost zero (when testing from an Ethernet attached device).

In your screen shot in post #7 your NAT acceleration was set to Level 1 CTF. Can you change this to Level 2?

It's weird I've tried 2 times now, and after it finishes loading, I lose connection to the router for a few seconds and when I go check the NAT acceleration, it's back to Level 1 CTF.

Tried it on the main router with the AP unplugged as well.

 

[ColinTaylor]

There was a similar problem in this thread (see the last post).

P.S. NAT acceleration is only applicable in router mode, so setting it on an AP has no effect.

 

[pierop]

There was a similar problem in this thread (see the last post).

P.S. NAT acceleration is only applicable in router mode, so setting it on an AP has no effect.

I could only try it on the main router as the router in AP mode doesn't even show the "Switch Control Tab".
I read through the thread, last post is talking about doing some stuff I'm not sure how to do
is he talking about this post? I have a different router than the OP in that thread.

Release - [Fork] Asuswrt-Merlin 374 LTS release 45EC

The next release 46E8 is now available https://www.snbforums.com/threads/fork-asuswrt-merlin-374-lts-release-46e8.68757/ LATEST RELEASE: Update-45EC 19-November-2020 Merlin fork 374.43_45ECj9527 ============================ Picks up a few fixes for problems reported since the last release...

www.snbforums.com

 

[ColinTaylor]

I think the moral of that thread was "when stuff makes no sense do a factory reset on router".