Slow Download - fast upload on cable and wifi

Question

So I'm having this issue with the really slow download speed and very fast download speed over cable and wifi. The network topology is the following:

Provider router and FO media converter (PON-TECH PT-47RW) in bridge mode => Asus AC-RT66U router (connected to lan 1 from provider router).

The speed tests I have done are the following:

laptop connected over cable to provider router - (73.44 Mbps download / 72.83 Mbps upload) http://www.speedtest.net/result/6983140310

laptop connected over cable to my asus router - (9.36 Mbps download / 64.59 Mbps upload) http://www.speedtest.net/result/6983164758

laptop connected over wifi to my asus router - (13.19 Mbps download / 42.59 Mbps upload) http://www.speedtest.net/result/6983158870

I have already tried other suggestions from various forums like turning off the firewall or WMM but that didn't help. I have also ran the tests using an old tplink TL-WR940N router and here's what I got:

laptop connected over wifi to my tp link - (21.81 Mbps download / 10.76 Mbps uplpoad) http://www.speedtest.net/result/6983146621

laptop connected over cable to my tp link - (12.51 Mbps download / 10.65 Mbps upload) http://www.speedtest.net/result/6983153018

The download speed over wifi is slighly faster but on cable is the same...

What could the problem be?

Summary
cable provider router - 73.44 Mbps download / 72.83
cable asus router - 9.36 Mbps download / 64.59 Mbps upload
wifi asus router - 13.19 Mbps download / 42.59 Mbps upload
cable tp-link router - 21.81 Mbps download / 10.76 Mbps
wifi tp-link router - 12.51 Mbps download / 10.65 Mbps

Solution 1

After trying all suggested things and setups, I asked the provider to give me the WIFI password for their device and now I am using their device's wireless network and plugged out my ASUS router.

I concluded that the router-to-router connection isn't working very well or there is some sort of limitation in their device on using another router connected the PON-TECH one.

Solution 2

In your ASUS Router Web Interface, under the Traffic Manager side menu item, is QoS enabled? if so, there are probably upload and download bandwidth fields. This could be the cause of your un-even throughput. Just turn off QoS on your ASUS router and run your test again. This is just an assumption because I don't have your router configuration file in front of me.

Comments

[DavidPostill]

We don't want links to results in the question. Please edit and add a small summary table.

[DSF]

Added a summary as requested :)

[Ron Maupin]

If you are running NAT on your router, disable that. NAT is resource intensive, and your provider router is already doing that. Double-NAT gives you nothing. In fact, you should probably disable routing (bridge mode) on your router.

[DSF]

Should I do that even if the provider router is in bridge mode?

[DSF]

I disabled the NAT but the internet stopped working. I believe that since the provider router is in bridge mode, it isn't doing any NAT-ing.

[Vomit IT - Chunky Mess Style]

This seems like a standard throughput limitation issue with the devices in the middle per their configurations. Connected directly to the ISP router you get the fastest throughput but when you connect to other network devices through to the ISP router you gets less throughput. Read over the throughput specs for each device in question per however those are configured and see if the specs say otherwise there should be more.

[Vomit IT - Chunky Mess Style]

This is a common hardware spec and also commonly an assumed issue when it's just a hardware limitation issue more than anything and the speeds can vary based on the router configuration too. As per asus.com/us/Networking/RTAC66U I see this i.imgur.com/1wDJiAw.png

[Vomit IT - Chunky Mess Style]

Lastly, not sure how you have the routers configured, but if you are connecting a router device to the ISP device via the non-ISP router's WAN port, then that could be the issue. I know based on tests I've done in the past, network routers seem to have less throughout from the WAN ports so configure it if that's the case so the non-ISP router's LAN ports connect to the ISP LAN ports or whatever. Stay away from WAN to LAN on the inside network if possible and configure it accordingly for you needs at this level if that makes sense.

[DSF]

I don't believe it's a hardware limitation because in other configuration this router had much higher speeds and using an old TP-LINK with much lower specs I get 20Mbps on WIFI using the same topology. The configuration is as follows: FO cable - provider device (which also acts as a router and it is configured in bridge mode and outpus the connection to lan1) - my asus router connected to that lan 1 to it's wan.

[DSF]

I'm starting to believe that the asus router is now faulty and should be changed.

[Tale Words]

A bit of a strange question but do you, by any chance, have Google Chromecast/Google Home on your network?

[DSF]

No, I do not have any of those. Today I have borrowed a router from a friend and with it, the download speed was also around 12 Mbps. That got me to think that there has to be something wrong with the provider device and tomorrow I'll call them to clarify the issue.

[Antony Gibbs]

If you could get your hands on a FritzBox it would give you a lot more information on what is going on

[DSF]

No, QoS is off.