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AX86U and AT&T 1 gig upload speed problem

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road hazard

Regular Contributor
I've had my AX86U for well over a year I think. With my old ISP, I had 400/40 service and life was good. Less than a year ago, I got AT&T 1 gig service and put their modem in passthrough mode and pointed it at my Asus router and for MONTHS, I've been trying to figure out why I'm only getting about 450-500Mbps on my uploads and after reading this thread .... I've come to the realization that the problem was maybe my router all along.

The difference between my situation and that thread is I'm not using wireless or a mesh setup. All my PCs are hardwired and when testing with iperf to a friend down the street with AT&T 1 gig service, or serving up files via FTP or uploading 20-50 gig files to Azure and AWS...... raw upload speed is about half of what it should be. Sure, speed tests all show 930Mbps up and down but real world..... I'm only getting about half of my upload speed. Currently, I'm on the 3.0.0.4.386_49599 firmware and same problem.

Reading more and more, I guess this router has some sort of hardware limitation when it comes to gigabit (upload in particular) speeds? I can always max out the download speeds but upload.....consistently about 50% less than what I'd expect.

Since I'll probably need to scrap this router, can anyone recommend a good replacement?
 
Disable all of the add-ons to free up the CPU to handle 1ge speeds.

Not sure it's a CPU load problem. When I'm uploading files or using iPerf to test things, only 1 of the 4 cpu cores gets to about 30%. The only options I have turned on are Traffic Analyzer and AI Protection. But yes, I'll give that a shot and disable those. Between work, my Plex server and kids playing games, I might need to wait until tomorrow morning to see if that fixes it. :) Unless turning those off won't kill the internet connection?
 
Not sure it's a CPU load problem. When I'm uploading files or using iPerf to test things, only 1 of the 4 cpu cores gets to about 30%. The only options I have turned on are Traffic Analyzer and AI Protection. But yes, I'll give that a shot and disable those. Between work, my Plex server and kids playing games, I might need to wait until tomorrow morning to see if that fixes it. :) Unless turning those off won't kill the internet connection?
To make sure those setting stick it is recommended you withdraw consent on the privacy tab under administration. This ensures all Trend Micro modules are disabled after turning them off. I do not remember if this causes an internet disruption (I don't think it does, but since you are working I wouldn't bother with it until you are done).
 
To make sure those setting stick it is recommended you withdraw consent on the privacy tab under administration. This ensures all Trend Micro modules are disabled after turning them off. I do not remember if this causes an internet disruption (I don't think it does, but since you are working I wouldn't bother with it until you are done).

I threw caution to the wind and did all of that and it made things SLIGHTLY better. Instead of getting my usual 450-500Mbps I'm now seeing a consistent 540Mbps but still not quite the 900+Mbps I should be getting. So..... looks like it's time to say goodbye to my AX86U. :(

I'm leaning towards the Synology RT6600AX or ....... ??? This gig upload problem with my AX86U has left me with a bitter taste in my mouth for all things ASUS.
 
There must be something more going on. I have no problem hitting 940mbps up and down on Quantum Fiber with the RT-AX86U.
Without AI Protection on I can also hit approx 860/860 mpbs up and down at the same time which is as good as 1Gig ethernet gets.... Only when I turn AI Protection on do I have an issue that total WAN throughput drops to around 1,400 (instead of 1,700) mpbs....

Quantum uses VLAN Tagging (VLAN 201) but nothing else and I am connected directly to the ONT.

I suggest you do a full factory reset and try without configuring much and see what the throughput is...

Also try to hook up a computer directly to the AT&T Router in passthru mode to make sure it's not the AT&T router that is causing the problem...
 
I'm leaning towards the Synology RT6600AX or ....... ??? This gig upload problem with my AX86U has left me with a bitter taste in my mouth for all things ASUS.

Let us know how another router performs with ATT in Passthrough mode... I was wondering if the ATT box reserves some upload capacity for its other services.

And I would also reset and configure the AX86U from scratch before thowing in the towel.

OE
 
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bitter taste in my mouth for all things ASUS.
When I upgraded to gig on cable I had been using a combo CM/router/wifi device which served me well until boosting the speeds and it only did 300mbps thus requiring going to D3.1 modem + router. Well, I plugged in an older Asus and it fell flat on its face when it came to speeds. I don't recall exactly but plugged into it and trying to get speeds near where a direct to CM were just pitiful. I tried the RT2600AC / R7800 and stuck with the R7800 for awhile before ditching it an making my own using a PC + PCI card to host an AP off of. Well, then came AX and there still isn't a PCIE card that does it which forced me into an AP which wasn't really a bad thing but, I liked my compact all internal design more.

The reason Synology didn't work for me was 160mhz didn't work well on it and the R7800 did work but over time they kept pushing tons of FW updates and causing more issues than they were fixing. I can't really say on any AX off the shelf router but, if you want to split the router / wifi function into 2 boxes there's options.

But, with anything tech related you can get 5 devices and they all perform differently. Some perform well and others are dismal in the same class.
 
As others have suggested, you should get close to 1Gbps uplink over WLAN-WAN (see SNB test charts below), and definitely peg 1GbE over LAN->WAN no prob. If not, then something is disabling your h/w acceleration. Also, Ai Protection does disable h/w acceleration, and is single threaded which is why you see it only pegging a single core.

https://www.snbforums.com/threads/huge-bandwith-limit-with-skynet-and-others.79456/#post-771055

https://www.smallnetbuilder.com/too...hz-profile-up/4730-asus_rtax86u?testmethod=44
 
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For your AX86U the Hard Factory Reset, AKA WPS Reset, may not clear all the router settings. Factory Reset with initialize all settings does seem to work all the time.

In addition to resetting the router using another Ethernet cable between the ONT/modem and the router is in order. When setting the AX86U up use the WAN port to the modem and not the 2.5 GB port.
 
For your AX86U the Hard Factory Reset, AKA WPS Reset, may not clear all the router settings. Factory Reset with initialize all settings does seem to work all the time.

In addition to resetting the router using another Ethernet cable between the ONT/modem and the router is in order. When setting the AX86U up use the WAN port to the modem and not the 2.5 GB port.
What's the reason for using the 1GbE WAN, instead of the 2.5GbE?
 
What's the reason for using the 1GbE WAN, instead of the 2.5GbE?
I had an issue setting up the router on the 2.5 port when connected to my Xfinity gateway's 2.5 port. I had to change the interval for trying to get an IP address from aggressive to normal. The Comcast box didn't like getting hit with so many requests in a short period. On normal it is reliable.
 
Also try to hook up a computer directly to the AT&T Router in passthru mode to make sure it's not the AT&T router that is causing the problem...

I just got done doing as you suggested. Took the PC I was doing all my testing with (and getting 450Mbps with iPerf all the time) and hooked it straight into the AT&T modem...... bypassing my AX86U entirely........ I carried out the same iPerf tests to my friend down the street with AT&T 1 gig and got this:

Code:
------------------------------------------------------------
Client connecting to x.x.x.x, TCP port 5001
TCP window size:  162 KByte (default)
------------------------------------------------------------
[  3] local x.x.x.x port 34500 connected with x.x.x.x port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1.08 GBytes   923 Mbits/sec

and now, going back through the AX86U:

Code:
------------------------------------------------------------
Client connecting to x.x.x.x, TCP port 5001
TCP window size:  208 KByte (default)
------------------------------------------------------------
[  3] local x.x.x.x port 61743 connected with x.x.x.x port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec   561 MBytes   470 Mbits/sec

...... after several tests, speed were (on average) about 935Mbps bypassing the AX86U and (on average) 460Mbps through the AX86U. I guess this means there is something with my Asus router :)

I'll do the factory reset (with initilization) later today or tomorrow morning and before I make ANY configuration changes, I'll do the iperf test again.
 
I have AT&T fiber as well, with my fiber gateway in IP Passthrough mode. Just as a sanity check, you aren't using any of the other LAN ports on the fiber gateway when you have your RT-AX86U connected are you? You shouldn't be doing that if you are.

Also, are you sure that IP Passthrough on your fiber gateway is actually working? Do you see your AT&T WAN address as your WAN IP on your Network Map page? If you see an internal, non-routable IP address there instead, you don't have IP Passthrough quite working yet. Also, you most likely know this, but you need to do more than "Apply" when you configure IP Passthrough, you have to actually power-cycle your fiber gateway before the new settings go into effect. Funky, but true *smile*.

Sounds like you've thoroughly reset your RT-AX86U...hopefully when you reconfigured it after that you didn't use a saved configuration file. In fact, I would go with defaults as much as possible in initial testing after a factory reset. For me, the WPS reset on the RT-AX86U has worked well to do as complete a reset as I've needed to do. There is the additional reset item that you can use if you use the router web admin interface to do the reset, you could try that, who knows, might help?

Needless to say, with my fiber gateway in IP Passthrough mode, when I'm on gigabit internet on my RT-AX86U, I see about 930/930Mbps. So full download and upload speeds that I expect to see. I don't know if what you're experiencing is having acceleration turned off, since I would expect to see both download and upload be slower if I had a setting on the router turned on that disabled acceleration. I really don't know what could be slowing down just the upload other than the above two items that I mentioned. A good test would be to try another router on your fiber gateway, but remember if you do that, you need to update your settings for IP Passthrough on the fiber gateway to reflect the new MAC Address on the other router.
 
I have AT&T fiber as well, with my fiber gateway in IP Passthrough mode. Just as a sanity check, you aren't using any of the other LAN ports on the fiber gateway when you have your RT-AX86U connected are you? You shouldn't be doing that if you are.

Also, are you sure that IP Passthrough on your fiber gateway is actually working? Do you see your AT&T WAN address as your WAN IP on your Network Map page? If you see an internal, non-routable IP address there instead, you don't have IP Passthrough quite working yet. Also, you most likely know this, but you need to do more than "Apply" when you configure IP Passthrough, you have to actually power-cycle your fiber gateway before the new settings go into effect. Funky, but true *smile*.

Sounds like you've thoroughly reset your RT-AX86U...hopefully when you reconfigured it after that you didn't use a saved configuration file. In fact, I would go with defaults as much as possible in initial testing after a factory reset. For me, the WPS reset on the RT-AX86U has worked well to do as complete a reset as I've needed to do. There is the additional reset item that you can use if you use the router web admin interface to do the reset, you could try that, who knows, might help?

Needless to say, with my fiber gateway in IP Passthrough mode, when I'm on gigabit internet on my RT-AX86U, I see about 930/930Mbps. So full download and upload speeds that I expect to see. I don't know if what you're experiencing is having acceleration turned off, since I would expect to see both download and upload be slower if I had a setting on the router turned on that disabled acceleration. I really don't know what could be slowing down just the upload other than the above two items that I mentioned. A good test would be to try another router on your fiber gateway, but remember if you do that, you need to update your settings for IP Passthrough on the fiber gateway to reflect the new MAC Address on the other router.

AT&T router is definitely in Passthrough mode. All ports are being forwarded as I had to go into the ASUS and forward some for Plex and a few other things. Single network cable goes from the AT&T modem into the WAN port of my ASUS router. No other devices hooked up to the AT&T modem. I don't see anything about 'hardware acceleration' unless it's tucked away somewhere?

You say you get 930Mbps up and down. I thought so too...... just by looking at speed test results. But when using iPerf and FTP uploading, I'm not getting the upload speed that speed test sites claim. Is your 930Mbps real world uploading? (Like cloud backup or ssh/scp transfers?)

I didn't reset the AX86U yet. Will do that tomorrow morning and test upload speed with iPerf before I do anything else. I won't restore my config via the backup file.
 
Sad to report that factory resetting my Asus router (both ways) had no effect. iPerf and FTP uploads are still in the 500Mbps range. :(
 
I have a similar upload issue on 1gbit Fios. Like you, straight to the ONT gives the expected results. It seems to be a lan to wan issue as it doesn't show if I use the internal router speed test or when I use iperf lan to lan. Also, interestingly it seems to be related to Windows based systems, because I get better results on Linux. Ookal's Speedtest is the worst. I get better results with the fast.com test and of course Verizon's speed test. I've been waiting 8 months for someone to identify and hopefully solve this problem, but nothing so far. If it wasn't for the fact that I get slightly better download performance with the AX86U, I'd probably switch back to a AC86U.
 

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