How to troubleshoot dropped internet?

[danageis]

I have (what I had thought) was a fairly robust home network: cable modem (older DOCSIS 2.0 Motorola surfboard) connected to main router, main router connected to 2 APs throughout the house through cat6 in the walls. APs are same model routers (TP-Link archer 7) configured w/o DHCP and connected only to LAN ethernet ports. Each AP is also used as an ethernet switch for PC and game console in separate rooms, but again nothing hooked into the WAN port of the APs.

My issue is that my internet has been dropping VERY frequently. By dropped, I mean that wireless network is still broadcasting but "limited", and even wired ethernet devices cannot connect to the internet.

Only fix I have found is unplugging all 3 routers and the modem, waiting ~30s and restarting all 4 devices.

My question is, is there a way I can figure out which devices are causing the problem, either by looking at logs are by doing some sort of troubleshooting when the network goes down?

2/3 of the routers are refurbished, and I have read online of some issues with these models, but I'd like to figure out which ones specifically are the culprits if possible.

I'd appreciate any help or insight, and also if you feel that my hardware is just too old/bad to bother with, do you have any recommendations?

 

[USAFRet]

1. This happens across all devices at the same time?
Call your ISP and see if something's up.

2. Give each router a different SSID. That way, you can maybe tell which ones are up or down.

 

[danageis]

It's not only that the WiFi network is down, but that the entire network can't connect to the internet (even wired devices, connected to any of the 3 router Lan ports). I have checked for outages during some of the shutdowns and the ISP says there are none.

 

[Sam Poland]

There could be a couple things happening here. If giving them different SSID's doesn't yield any results put them all back on the same SSID but make sure they are each using a different channel. Since you have 3, use channels 1,6 & 11. This is counter-intuitive but that's why most people make the mistake of having all their AP's on the same channel. I would also get a DOCSIS 3 modem. In Cal. I know Charter provides them. I don't know that either of these is the fix for your problem. I do know it's best to have your network conform to 'best practices' in order to aid in your troubleshooting efforts.

 

[Sam Poland]

Here's a link that includes some info about the 5GHz bands:

https://www.extremetech.com/computing/179344-how-to-boost-your-wifi-speed-by-choosing-the-right-channel

 

[danageis]

Hi Sam, yes that is currently how I have the network configured, same SSID channels 1/6/11. I'm not sure I understand the separate SSID check suggestion. Maybe I haven't explained correctly, but when the network drops, I can't even connect online with a wired connection to ANY if the 3 routers, so I don't understand how naming SSIDs differently would help me.

If the idea is to check if a certain SSID goes down when the crash happens, that is not the case. I've using wifi analyzer on my phone to manually connect to the SSID on each of the 3 bands, and when the crash occurs I cannot get internet access on any of the bands (each coming from a different router) - they all appear as available networks, but connection is limited when I connect and I cannot access the internet.

I guess I was more hoping, is there a way to tell if the problem is my modem not able to connect to my ISP for some reason, or is one of the routers causing an issue in the network? Is there a way I can troubleshoot that? Since the network stays up, I should have local access to the routers, is there any kind of terminal tool or log that would help me diagnose this?

 

[Sam Poland]

Is it possible to leave the other 2 routers disconnected long enough to see if the problem persists?

 

[danageis]

Hmm, that is something I haven't tried, but the main problem is that I need the 2 APs to use as ethernet switches. Both of them are hard wired to at least 3 devices

 

[USAFRet]

It's not only that the WiFi network is down, but that the entire network can't connect to the internet (even wired devices, connected to any of the 3 router Lan ports). I have checked for outages during some of the shutdowns and the ISP says there are none.

Your ISP specifically said they can see your network (modem and/or router), when you cannot get to the outside world?

Everything being affected is either your modem/router, or outside your house.

 

[danageis]

I asked the ISP the last time it dropped (yesterday afternoon), and they fixed it by remotely rebooting my modem. I also learned how to view logs on my modem, and every time the internet has dropped it has been logged as a connection error in the modem log. I think the router resets 'fixing' my issues were just coincidental with the issue really being fixed by rebooting the modem. I'm still not sure why the modem keeps dropping connection (from what I've read online, the signal values on the modem are all within acceptable range), but regardless I don't think this forum is going to be able to help me diagnose cable modem issues. Thank you all for your advice. If anyone thinks I am wrong about the cause of this and has some more advice on troubleshooting my cascade configuration please feel free to let me know.

 

[USAFRet]

"connection error" in the modem log would point (to me at least) to be an issue outside.
The modem can't talk to the ISP equipment.