What are the best ways to debug this home network problem?
November 18, 2023 10:29 AM   Subscribe

Portions of our home network are not reliable. Should I replace the main wireless router? What tools and methods can I use to test and monitor network activity?

Our network consists of the following:
- A Motorola MB7621 Cable Modem attached to our outside service.
- A TP-Link AC1750 WiFi Router. This router creates WiFi Network A.
- A TP-Link WiFi Access Point TL-WA801N connected via 100 foot Ethernet cable to the router. This Access Point creates WiFi Network B.
- A 100 foot Ethernet Cable plugged into the router, that is then plugged directly into computers to create a Wired Connection.

The behavior:

WiFi Network A is reliable, but does not reach everywhere in the house.

We set up WiFi Network B to provide network access closer to the bedroom that wasn't serviced by Network A. This didn't work reliably, so we moved on to the Wired Connection.

The Wired Connection seemed to work reliably for about a year (our memory on this is vague) but has recently become very unreliable. We replaced the 100-foot Ethernet cable used by the Wired Connection, but the new cable didn't fix the problem.

When I use the Wired Network, it works fine except when I'm on video calls. When I try to do Zoom/Google Meet/Microsoft Teams calls, I get bad dropouts. It's not reliable enough to be used, and I have to work in a different location. I haven't tried Wireless Network B much, but another family member says it is also unreliable. The other family member often can't get any work done, including things like using docs, from that location using the Wired Network or Wireless Network B. But sometimes they can get work done fine, for hours on end. It's unpredictable.

Three questions:
- Should I try shorter Ethernet cables? A 50 or 75 foot cable would probably work.
- Should I just bite the bullet and buy a new wireless router with a bunch of Ethernet ports to replace the router currently used for Network A, and hope that it is more reliable? Is there a brand and model you would recommend?
- What are some tools and techniques I can use to test and monitor the network? Given the intermittent nature of the problems, I can't just, for example, replace a cable, do a test, and see whether it works. I could try doing a half hour zoom call with someone, but that's not very convenient. Short of immediate testing like that, is there an application I can run on a Macintosh or Windows 11 computer that will continuously monitor the network quality, and report dropouts?

Thanks very much for any thoughts and suggestions.
posted by Winnie the Proust to Computers & Internet (6 answers total)
If things are glitchy with video calls on wired Ethernet, I would start wondering about your cable modem or cable connection overall. A few years ago my Spectrum connection was godawful, especially for video calls, since upload for cable modems is weak sauce in the first place. Spectrum couldn’t have cared less of course. Fortunately, there was a fiber option, which cost about the same and was totally transformative.
posted by rockindata at 11:04 AM on November 18

Response by poster: Video calls are fine on Wireless Network A. Everything is fine on Wireless Network A except that it doesn't reach some parts of our home.
posted by Winnie the Proust at 11:20 AM on November 18

If you're having trouble on any device connected to a hard-wired connection to the TP-Link A7's LAN port, and also having trouble with any devices connected to another device hard-wired to a different TP-Link A7 LAN port, but no problems connecting via wireless to the A7 (aka WiFi Network A) itself, the issue almost certainly has to do with:

1) The way that the A7 is routing the LAN ports. This could be either a settings issue or firmware bug on the A7.
2) The specification of all the cables used to hard-wire the devices to the A7.

I would first check the "NAT Boost" and "Duplex" settings on the A7, which are in Advanced -> System Tools -> System Parameters. Make sure NAT Boost is disabled, and if it isn't, disable it and reboot the A7 and test.

I would then check the "Duplex" setting and set it to "Full 1000mbps" if it's not already. Try rebooting the A7 and test again.

If that doesn't help, try changing it to "Full 100mbps", reboot, and test again.

I'd also check to see if there's a more recent firmware for your A7.

If you're still having issues, I'd check on the sides of your 100 foot cables to see if they're rated CAT6 or higher. If they're CAT5 or CAT5e, I'd consider replacing them with CAT6 or CAT6a cables next.

If all that doesn't work out, it might be time to replace the A7 with a modern mesh router and remote mesh extenders. There is certainly further testing that could be done but it depends on how far down the rabbit hole you want to go and how much time you want to spend. Recommending a system is difficult without more specifics on budgets and goals, but I'll bet there will be Black Friday sales on the well-regarded Eero 6 systems, and I've often recommended Google Nest systems for the sake of reasonably simple setup and good performance.
posted by eschatfische at 12:06 PM on November 18 [3 favorites]

1) I'd still start by checking the modem event logs. There should be a sticker on the bottom of your modem with login info, but typically for this modem it's:
(type this address into a browser)

user name: admin
password: motorola

Look for event logs and see if there are multiple instances of timeouts (typically a T3 or T4 timeout). This would indicate a problem outside the house that's causing a flakey connection. (This happened to me with a line to the house with a cracked housing that was letting in moisture.)

2) Do you know what type of ethernet cable you are using? Cat 5, Cat 5e, Cat 6, Cat 6a? If the cable is old/bad it could be limiting speeds, which might only present itself in more bandwidth intensive applications like video calls.

3) A relatively cheap test would be to buy a brand new Cat 6a ethernet cable, turn off your wifi connection for your computer, plug in directly to the router, and test video calls. If the video calls are fine, it's likely not a hardware issue with the router but more likely a cable issue. If it's still bad then maybe it's flaky ethernet ports or general flaky hardware on the router which is making everything else connected to it flaky.
posted by bluecore at 12:06 PM on November 18 [1 favorite]

Is the ethernet cable crossing any AC power cords that would cause interference?

if you open up a command prompt, start the command ping (or ping -t on windows)

It'll stop, time out, or show an error when things go south.

The TP-Link app can be helpful configuring their devices.

In the past I have seen issues with separate Access Points with bad MTU (Maximum Transmission Unit), or how big it's "packets" of information are.

Then when the AP / Router send that packet into the Cable Modem, if it's a much smaller MTU, the routing table gets overloaded with all these small shards. So if you can reduce the MTU on the Router and AP to the same size, it may help keep the Modem happy.

posted by nickggully at 5:39 PM on November 18

Response by poster: Thank you all for this great and detailed advice.

I updated the router firmware and turned off NAT Boost as suggested by eschatfische. We haven't had any outages since then, though we haven't used the networks very heavily. I also checked the modem logs following bluecore's suggestion, and didn't find anything concerning.

Our cables are all Cat 6, and they don't cross any AC power cords.

The one other thing I did was turn off and disconnect our Synology NAS. Once I've established basic network reliability, I'll turn that back on and see if we run into any problems.

Thanks again for all the suggestions. It got me on track and hopefully things will be more stable from here out.
posted by Winnie the Proust at 12:35 PM on November 25

« Older U.S. Citizenship Gift Ideas?   |   Please help me give these 1950s plastic... Newer »

You are not logged in, either login or create an account to post comments