Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card

Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card
Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card
2020-08-31 11:24:19 - last edited 2020-09-07 22:09:29
Hardware Version: V1
Firmware Version: Firmware Version:0.9.1 0.0 v004a.0 Build 180816 Rel.31879n

Hello you network guru's out there. I'm looking for help with a very strange issue which is happening in my home network.
It might ba a CISCO related, but you are network specialists, you can point me the right direction at least.

 

Intro:

I have a 4G Internet connection from O2 using their TP-link Archer MR200 router with 20/2 Mbps (Down/Up) connection.
This Archer is connected via ETH to my other router ASUS RT-AC55U in AP mode to extend the Wi-Fi signal across the house and garden.
This works just fine and I have good connection for wired and wireless devices across the house and the speeds are ok.

 

Recently I decided to "upgrade" (don't laugh! :) ) to wired VDSL O2 connection with speeds 50/5.
To connect this to my existing home network I use an old CISCO 886VA route IOS 15.3.

 

Now the problem I have:
When I set up the connection from O2 on my CISCO router, I get very good speeds (like 57Mbps / 15Mbps) on the CISCO router itself (show controller vdsl 0).
When I connect my laptop to the CISCO ETH ports and do a Windows 10 Network speed test, I receive 50+Mbps download and 5+Mbps upload speeds regularly. Thats OK.
When I connect my TP-Link router to the CISCO router (set it up to get WAN from WanETH port not from 4G Sim card) and connect my laptop to the TP-link ETH ports, I also get full speed.
But when I try to connect my laptop to the TP-LINK Wi-Fi, I only get 0,42Mbps download and 5+Mbps upload!
I have even tried replacing thet TP-LINK MR200 with another, older wi-fi router I have here (also TP-LINK unfortunately) but its exactly the same 0,42 D 5+ UP. On all wireless devices I have at home.
The strange thing is, when I try to go to a web page while wirelessly connected, it shows the texts, but doesn't load the pictures or other multimedia content.
On the other side, when I try to go to Youtube and play a 4k video, it has no issues whatsoever to play this high quality, bandwidth demanding video stream while I'm wirelessly connected to my TP-LINK.

I'm kind of puzzled here. Don't know where to look for the issues.
I can ping all IP's, I have the DNS set OK, what I'm not entirely sure of is the NAT and why UDP media (video stream from YT is OK, and from other pages it is not even loading up).

I can share the network diagram for you to see the whole picture and I can share the configs if you need them to better understand the setup.

Now I'd be very grateful if anyone can advise where to look for issues with the slow Wi-Fi download speeds. I'm suspecting issues at the TP-Link config, but don't know what to look for.

Thanks
 

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Re:Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card-Solution
2020-09-07 22:09:06 - last edited 2020-09-07 22:09:29

Hi All, the culprit has been found! 

After tweaking the MTU size (1400) and the Maximum Segment Size (MSS) (1360) in my CISCO router, the connection is now flawless. 

Thanks to everyone participating and especially to the CISCO guys out there who helped me out identifiyng it. 

 

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5 Replies
Re:Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card
2020-08-31 12:09:13
Wow... what a setup. Nice graphic. What I would do is disconnect the Asus Ethernet cable to the MR200 and power down the Asus and the WR353ND. Then trouble shoot the MR200 WIFI issue. Once that is resolved, bring back one device at a time. I suspect interference on your WIFI. Are you using 2.4 GHz or 5 GHz? Are you using any of the same SSIDs, and/or the same channels numbers? Note that some channels overlap a bit so channel selection may be key here. See https://www.duckware.com/tech/wifi-in-the-us.html for more info on overlapping channels. How close are the routers to each other as to close can cause issues. Actually what I would do is consider a true Mesh system such as the Deco M9 but I understand working with what you got. Let us know what you find.
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Re:Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card
2020-08-31 13:06:00
The routers are in the same house just on different floors separated by wooden floor/ceiling and approx 4-5 meter distance. The problem won't be in Wi-fi overlaping/interference as it just works OK in exactly the same Wi-fi setup when the source of the internet is the TP-LINK 4G sim card. It only does this, when the source of internet is the WAN Ethernet port on the Archer.
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Re:Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card
2020-09-01 20:07:14

@Waran666 

 

Are all three wireless nodes configured to have the same network name? If so, your device may be getting confused connecting to the furthest device.

 

Make every wireless network a unique SSID.

 

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Re:Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card
2020-09-01 20:15:07

@Tony yes Tony, they have the same SSID. I wonder how would you explain the fact that I'm mentioning in previous posts that when I switch the "internet source" from Ethernet WAN port back to the 4G SIM card (3G/4G Router Mode) and leave everything the same, the wifi works OK.The download is full speed and the upload is full speed. 

But when I switch the TP-LINK router to "Wireless Router Mode" and connect Wan cable with 50/5 speeds, then only the upload is full speed and the Download is always only 0,42! 

??? 

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Re:Very low download over Wi-fi when WAN is set for EthWAN and not 4G SIM card-Solution
2020-09-07 22:09:06 - last edited 2020-09-07 22:09:29

Hi All, the culprit has been found! 

After tweaking the MTU size (1400) and the Maximum Segment Size (MSS) (1360) in my CISCO router, the connection is now flawless. 

Thanks to everyone participating and especially to the CISCO guys out there who helped me out identifiyng it. 

 

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#6
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