R7800 poor WAN download upload rate when a client is connected at 100Mbps

[sppmaster]

Latest stock firmware.

Just found out a new unpleasant discovery. WAN slowdown bug when there is simultaneous LAN traffic with 100Mbps device involved in the LAN traffic.

I have 3 devices connected to the R7800 LAN ports - two Android TV boxes and a 4K TV (all with 100Mbps NICs! This is really important to trigger the bug).

A desktop PC is connected at 1Gbps to the R7800 LAN port 4. There is a Plex server installed on the desktop PC.
When a 4K movie with bitrate ~70Mbps is played on the TV box and on the 4K TV set, the Internet (WAN) download/upload speeds on the desktop PC or on any other device connected by cable drop dramatically from 940/680 Mbps with 1ms ping to just anything between 25-350/100-200Mbps. The speedtest results are really low and inconsistent (varying hugely from as low as 25Mbps to 350Mbps) with high ping from 50 to over 350 ms.
I can hardly reach the speeds on the below picture during a LAN traffic from a desktop PC streaming two 4K movies with video bitrate around 70Mbps to Android TV (playing the movie) and Android Set-top box.

I can reproduce this using iperf3 to create LAN traffic between two or more LAN clients.

If I connect a Laptop with 1Gbps connection instead of 100Mbps device, the WAN slowdown doesn't occur.

But it does occur when I connect the same Laptop but with 100Mbps cable (4 wires).

I have this WAN down/up speeds limitation only during active LAN transfer/s between a PC and another 100Mbps LAN client/s. You need simultaneous WAN and LAN transfers. I use iperf3 to better shape the scenario.
Otherwise this doesn't occur.
For me this is unacceptable because when anyone is watching on a TV set (100Mbps) movie streamed over a LAN (PC at 1Gbps as a server - TV set as a client) the PC (1Gbps) can download/upload from/to WAN at very low speeds. And all other 100 Mbps devices involved in LAN transfers cannot download either.
A separate Laptop connected at another port at 1Gbps can download at full speed from WAN as long as it doesn't take part in simultaneous LAN traffic with another 100Mbps device.
Obviously a complicated but real life scenario.

I've used three routers - two different R7800s (to reject it is a hardware problem only) and cheap no-name gigabit router with Ralink chipset.

The cheap router doesn't have this issue when performing absolutely the same tests. It easily achieves simultaneous full WAN/LAN speeds.

[FURRYe38]

What Firmware version is currently loaded?
What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

Tried installing a non managed Gb LAN switch in between the router and these devices? 

What CAT# Lan cable are you using? CAT6 is recommended.

Is QoS, Armor, or Traffic Meter enabled on the router? 

Has a factory reset and setup from scratch been performed since last FW update?

Something I don't see with mine:

https://community.netgear.com/t5/Nighthawk-WiFi-Routers/New-firmware-for-the-R7800/m-p/2207085/highl...

Though my 3 Dish network Joeys are connected behind switches...

[sppmaster]

R7800 Firmware Version 1.0.2.90

I've tried with non managed Gb LAN switch but as long as there are devices connected at 100Mbps and they transfer over LAN the WAN speeds drop dramatically.

None of the QoS, Armor, or Traffic Meter are enabled on the router.

Factory reset and setup from scratch doesn't make any difference.

I stress that WAN speeds drop occur only when there are 2 or more devices connected at 100Mbps that transfer data over LAN (I use iperf3 here to reproduce/trigger the WAN bug) and you perform WAN speed test at the same time from desktop PC connected at 1Gbps that takes part in LAN transfers too (around 200-300 Mbps LAN traffic to both 100Mbps clients). Sometimes WAN speed is still decent but there are LAN speed drops.

This doesn't happen if all the devices are 1Gbps. Only happens with two or more 100Mbps devices connected taking part in simultaneous WAN and LAN traffic.

[FURRYe38]

I'd be curious if Voxels 3rd party FW does the same thing.

What is the brand of model of the switched you tested with? 

What CAT# cables are you using?

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

[sppmaster]

Yep, the bug is present in stock, Voxels and OpenWRT firmwares.

The cables are OK because noname cheap router for 20 bucks doesn't have this issue with all the tests repeated using the same network setup and environment.

[FURRYe38]

What is the brand of model of the switched you tested with? 

What CAT# cables are you using?

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

[sppmaster]

The cables are OK because noname cheap router for 20 bucks doesn't have this issue with all the tests repeated using the same network setup and environment.

The slowdown happens no matter if I use or don't use a switch in the setup.

A presence of 100Mbps connected devices is compulsory to trigger the bug.

It doesn't happen if only 1Gbps clients are connected.

[FURRYe38]

Well since we can't get the details, seems like you should contact NG support and let them know what your seeing. Seem to be your next step. 

Good Luck. 

[sppmaster]

The issue is present without any additional switch - but here it is TP-Link LS1005G.

Cables - CAT.5E

ONT Alcatel-Lucent I-010G-U

Hope all this helps.

[sppmaster]

At this time I can only speculate that there should be easy fix for this because if only 1Gbps devices are connected to the LAN ports and no matter what LAN and WAN traffic combinations are performed, all data flawlessly goes at Gigabit Full Duplex speeds from/to WAN and LAN simultaneously or not.

But once there is only one 100Mbps device connected to any LAN port and it sends/receives data over LAN the WAN/LAN performance drops significantly.

WiFi is not affected by this bug, only LAN ports.

The paradox is that a 100Mbps device shouldn't put even a light load on the Gigabit device but in this case the result is awful.

[FURRYe38]

So was interested in testing this with my R7800 router mode v.90 FW loaded connected to a CAX80 in modem mode on a 1Gb port. 

I found a couple of old 100Mbps NG routers from ages ago. WGR614v5 and a WNDR3400v1.

Set them up for AP mode and connected them via LAN cables to the R7800. 

Ran a speed test here on the wired Mac Book Pro with the R7800 alone:

I took a speed test with a Mac Book Pro 2018 after turning on the old 100Mbps APs:

No streaming happening at this point.

I connected a Galaxy Tab S2 to the 614 2.4Ghz only and my IPhone 12 pro Max and a older IBM Think Pad Laptop with Windows 7 on it and connected these two to the WNDR3400 on 5Ghz. 

Set up the Tab S2 and IBM laptop for youtube and set Halo Forward Unto Dawn for max resolution and started playing the video on both. 

Captured a speed test with the Mac Book:

Didn't notice any significant drop in speeds. 

Both Tab S2 and Laptop and phone had updates available so I triggered these as to get a bit more saturation from the system:

After compiling the screen captures and inputting them in to this post I took one more speed test with the Mac Book about 5 minutes later:

Unless I'm not saturating the system enough or there is a different configuration between yours and mine or possibly your devices are causing some bad behavior when connected or your R7800 maybe having HW issues, I can't see any issues with having 100Mpbs devices connected. Not once has the speed dropped significantly on the R7800 with having 100Mpbs devices connected. 

[sppmaster]

Thanks for your input here.

I think with your setup you may not notice this.

The WiFi is not affected by this bug, only LAN ports that have simultaneous WAN and LAN traffic going through them with at least one 100Mbps device connected to any LAN port but also transferring data over LAN.

Here is my network setup

First I run iper3 server on a PC (1) as a LAN server connected at 1Gbps. Then I run iperf3 as a client with -R (reverse option) on a client device (2) Laptop connected at 100Mbps with 4 wires cable (that's what triggers the bug). It doesn't matter if the connection of device 2 is directly to a router LAN port or to the same port via second switch (Gbit or not).
I run network traffic from PC server (1) to all three (2, 3 and 4) 100Mbps clients. Total around 300Mbps going from the PC (1) to clients 2, 3 and 4 at the same time.

Finally I run WAN speedtest on a PC (1) connected at 1Gbps. The PC (1) WAN down/up speed drops significantly.
When I run WAN speed test on PC (1) I have ridiculous WAN performance varying from 20-30Mbps to maximum 40-50Mbps with ping increasing to 50-500 ms (normally 1ms). WAN upload speed is negatively impacted too. I have 700Mbps from my ISP but am able to achieve 150-200Mbps at most. Sometimes speeds are little bit higher but all LAN transfers are interrupted during the WAN test.
With this setup If a client device (2) is connected at 1Gbps to LAN port 2 (I use the same Laptop and just change the cable with 1Gbps one) and it doesn't send any data to any other 100Mbps device over LAN then the Laptop (2) can download/upload from/to WAN at full Gigabit speeds. Even if the PC (1) cannot do this because it sends data to any other 100Mbps device.
Obviously the router LAN port, through which the LAN data is sent to 100Mbps device connected to another port, cannot receive/send data at Gigabit Full Duplex speeds to WAN in this case.

If I use second Gigabit switch it becomes a real nightmare because even more 100Mbps devices are present on the LAN part and none of the 100Mbps devices (connected to the second switch) cannot download form WAN at more than 1-2Mbps even if only one of them is involved in LAN traffic (sends or receives data to PC server connected at 1Gbps).

In the network setup above if all devices 1, 2, 3 and 4 are connected at 1Gbps the WAN and LAN performances are great. Even if the PC server (1) sends data at 930Mbps through the LAN to 2, 3 and 4 (now all are connected at 1Gbps) at the same time it's still possible to download from WAN on a PC (1) at 930Mbps. We have expected Gigabit Full Duplex performance - 930Mbps download (with 1 ms ping!) from WAN on PC (1) and simultaneous data sending over LAN from PC (1) at 930Mbps to other LAN clients.

I've used two different R7800 routers with three different firmwares with default and custom settings. The results are repeatable every time.

Unfortunately all current TVs and other AndroidTV boxes only have 100Mbps NICs.
With another really cheap Gigabit router for 20 bucks I'm able to download and upload from/to WAN from PC (1) at Gigabut FD speeds 930/670 Mbps with exactly the same network setup running same tests.

[FURRYe38]

Understand that when I connected the WNDR3400 and WGR614, these were LAN cable connected to the back of the R7800, thus these two devices I used to emulate your devices, only support 100Mbps. I was using the wifi on these devices to get traffic flow over the 100Mpbs LAN connection to these wireless AP to check if anything was disserable with a drop in speed on my R7800 and having two 100Mpbs devices connected. The LAN LEDs on the R7800 were amber thus indicating a 100Mpb connection. My Mac Book Pro was connected at 1000Mpbs thus the LED on the router was WHITE. 

Possible that the two devices you have connected maybe causing this problem, if it happens across two different same model routers and different FW versions. I kind of doubt the router HW is faulty. 

If you wan to keep using the R7800 with these devices, I would recommend and suggest the following, put in a good quality LAN 1Gb LAN switch in between these two devices and the router to see if this helps alleviate this issue you see. Or connect up a wireless client bridge to each of these devices and connect them via wireless to the router. This should work in these two configurations. I've had a wireless bridge connected to a DISH joey for connection to the system. Works well. 

Otherwise you'll need to contact NG support and let them know about this. Would be nothing else we can do here in the forums. I can only presume they will take a look at this and see if they can fix it. However since your the only one thats reported seeing this, not sure how much traction it will get or get fixed at all if it's reproducible at NG. Also a fix would not come over night. 

Good Luck. 

[sppmaster]

Thank you.

I understood really well what you wrote.

That's why I told you that probably you won't notice the bug. It's complicated and most people will never notice this. Once again Wireless is not affected by this bug, only LAN ports.

It's not enough to just have several devices connected at 100Mbps and they download from WAN.

The compulsory condition is real LAN traffic between at least two LAN devices - one of them 1Gbps device (PC as a file server) and second 100Mbps device. The best is if you have three or four devices as described below. There should be data transfer between those 100Mbps LAN devices and a 1Gbps device. At the same time you have to run the WAN speed test on the 1Gbps device (PC file server).

First I run iper3 server on a PC (1) as a LAN server connected at 1Gbps. Then I run iperf3 as a client with -R (reverse option) on a client device (2) Laptop connected at 100Mbps with 4 wires cable (that's what triggers the bug). It doesn't matter if the connection of device 2 is directly to a router LAN port or to the same port via second switch (Gbit or not).
I run network traffic from PC server (1) to all three (2, 3 and 4) 100Mbps clients. Total around 300Mbps going from the PC (1) to clients 2, 3 and 4 at the same time.

Finally I run WAN speedtest on a PC (1) connected at 1Gbps. The PC (1) WAN down/up speed drops significantly.
When I run WAN speed test on PC (1) I have ridiculous WAN performance varying from 20-30Mbps to maximum 40-50Mbps with ping increasing to 50-500 ms (normally 1ms). WAN upload speed is negatively impacted too.

On OpenWRT forums there are several other people confirming the same behaviour.

Putting a second gigabit switch make things a nightmare.

In my setup I have a Gigabit switch and I have even more 100Mbps devices connected and then the things go really bad. 20-30 Mbps WAN download with ping over 250-300ms and none of the 100Mbps devices cannot download form WAN at more than 1-2Mbps even if only one of them is involved in LAN traffic (sends or receives data to PC server connected at 1Gbps).

I've tried two different gigabit switches and two different gigabit routers in addition to the two R7800 routers.

[FURRYe38]

Also that kind of configuration is a testing configuration as well. Not normally seen out here in the real world or in the average home user. So again something that maybe particular to your configuration and environment. Overall, if you feel this is a bug, you'll need to contact NG support and let them know. 

Good Luck. 

[sppmaster]

I think the setup is trivial because nowadays the home TV service is managed mostly by ISPs over fiber-optical networks.

It's normal to have 4-5 TV sets (all with 100Mbps NICs) at home. It's normal that more and more people have NASes, File Servers, DLNA, Video Surveillance Systems and a pile of other network devices. 

In my case when someone watches a movie, streamed over LAN from PC file server to a TV set, on a second TV HBOMax cannot be watched normally because the WAN speed to the TV is low. HBOMax needs 20Mbps average bitrate but the TV device can achieve 5Mbps or even lower.

All of this won't remove or cure the bug. That's why I report here and all owners can test and confirm it.

I'm sure that other users suffer from the same WAN/LAN performance drop but they are simply unable to find the reason for this.

If Netgear really care for its products and clients they should fix this ASAP.

[FURRYe38]

Not all devices now days are 100Mbps supporting, some are 1000Mbps so again may not see this in most average homes and most users like to use the wifi features of TVs when they can. Again, you've been the only one posting about this. So not to say that there isnt' a bug however not everyone seems to be seeing it and again, not using your same devices nor your configuration. I'm not seeing it with my setup. 

Its your responsbility to let NG know about and hopefully they can review and if it's something they can reproduce, fix it. Let them know for sure. Otherwise, you'll need to find alternatives. Again, fixes don't come quickly. So you have your information. 

Good Luck. 

[sppmaster]

Unfortunately I cannot open a support case with Netgear Support.

I just get a message stating that complimentary technical support expired on 2021-05-02

Does anyone have a suggestion?

[FURRYe38]

What FW is loaded on the R7800.

What is the brand and model of the host wifi router the R7800 is connected too? 

How is the wifi configured on this router? 

Whats the distance in between the host router and R7800?

[sppmaster]

Firmware - 1.0.2.90

R7800 is connected to ONT Alcatel-Lucent I-010G-U via 1.5 m cable.

ONT Alcatel-Lucent I-010G-U doesn't have Wi-Fi.