One device drags entire home network down

[newnews]

Hello,

I am using Asus RT-AC68U with 386_7.2 firmware. I experienced strange but very annoying issue. Sometimes all my devices(computers/phones,etc.) lost the internet connection and cannot get ip from the router. I also cannot login to router from the computer with static ip address(I use static ip address for desktop PCs). Cannot ping the router as well. After spending some time to troubleshoot, I found the problem is on one computer that went on sleep. If I disconnect the ethernet cable from it, the home network restored, everything works again. I turned on that computer, connect back the cable, no issue at all. I then put it to sleep, the home network is still working fine.

Some weeks later, the same issue occurred again but causing by another computer. Same method(disconnect ethernet cable, turn on computer and reconnect the cable back) to solve the network outage.

It seems a random issue but it all happened on computers with wired ethernet connection. The computer is either at sleep, off, or non-responsive state when it is causing network issue.

It happened on previous version of merlin firmware as well.

I don't understand why a single device could cause entire network problem when there is no physical issue i.e. wire short-circuit/grounded/voltage drop/network adapter failure. To me it is more like software issue because Asus router stop assigning IP addresses.

Any advice? Thanks

 

[ColinTaylor]

It's been known before (rarely). An old/bad network card drags down all the Ethernet ports on the switch (in this case the router's). The best solution is to replace the Ethernet card. If that's not possible there might be something you can do on the problem PC with the driver or perhaps in the BIOS.

 

[Kitsap]

Hello,

I am using Asus RT-AC68U with 386_7.2 firmware. I experienced strange but very annoying issue. Sometimes all my devices(computers/phones,etc.) lost the internet connection and cannot get ip from the router. I also cannot login to router from the computer with static ip address(I use static ip address for desktop PCs). Cannot ping the router as well. After spending some time to troubleshoot, I found the problem is on one computer that went on sleep. If I disconnect the ethernet cable from it, the home network restored, everything works again. I turned on that computer, connect back the cable, no issue at all. I then put it to sleep, the home network is still working fine.

Some weeks later, the same issue occurred again but causing by another computer. Same method(disconnect ethernet cable, turn on computer and reconnect the cable back) to solve the network outage.

It seems a random issue but it all happened on computers with wired ethernet connection. The computer is either at sleep, off, or non-responsive state when it is causing network issue.

It happened on previous version of merlin firmware as well.

I don't understand why a single device could cause entire network problem when there is no physical issue i.e. wire short-circuit/grounded/voltage drop/network adapter failure. To me it is more like software issue because Asus router stop assigning IP addresses.

Any advice? Thanks

On the suspect computer, go to the control panel device manager and check the properties and power setting for the network card. There is an option to turn off or leave on power to the network card when the machine goes into sleep mode.

The computer manufacturer or network card manufacturer may have updates to the network card drivers that do not install via Microsoft.

 

[Tech Junky]

Since it's stated that this is on multiple PCs replace the router and your issues should go away.

 

[newnews]

It's been known before (rarely). An old/bad network card drags down all the Ethernet ports on the switch (in this case the router's). The best solution is to replace the Ethernet card. If that's not possible there might be something you can do on the problem PC with the driver or perhaps in the BIOS.

The PCs are not old, one is just 2 months old and another one is 1.5 years. Indeed, Other older PCs(about 6-10 years old) never caused issue. Also the two computers are connected to router through a unmanaged switch. Switch has been replaced but problem is still occurring.

 

[Tech Junky]

Switch has been replaced but problem is still occurring.

Replace the router.

 

[newnews]

Since it's stated that this is on multiple PCs replace the router and your issues should go away.

But if PC is on, I never had problem.

On the suspect computer, go to the control panel device manager and check the properties and power setting for the network card. There is an option to turn off or leave on power to the network card when the machine goes into sleep mode.

The computer manufacturer or network card manufacturer may have updates to the network card drivers that do not install via Microsoft.

All my wired connected PC has same power settings for wake-on-lan. Tried different drivers. It occurs randomly and very infrequent.

 

[newnews]

Replace the router.

I can try another router, but it may take months to verify the result.

 

[Kitsap]

But if PC is on, I never had problem.

All my wired connected PC has same power settings for wake-on-lan. Tried different drivers. It occurs randomly and very infrequent.

Maybe we did not communicate. Do you allow your computers to turn off the power to the network connection when the computer goes into sleep mode?

 

[laracroftonline]

it’s the 386.7.2 firmware try using 386.5.2 and your network will be stable again.

 

[newnews]

Maybe we did not communicate. Do you allow your computers to turn off the power to the network connection when the computer goes into sleep mode?

View attachment 44191

yes, I ticked all three.

 

[newnews]

it’s the 386.7.2 firmware try using 386.5.2 and your network will be stable again.

sure can have a try

 

[drinkingbird]

sure can have a try

It is entirely possible that it isn't actually the PCs, but the process of unplugging and replugging (perhaps them renewing their DHCP lease, sending ARP requests, etc) somehow "wakes up" the router. Make sure you're not causing a loop of some sort, do the PCs also have a WIFI card in them or some other way of connecting between each other? There is some possibility that when they go to sleep, they're bridging all their connections or something causing a loop and drowning out your switch and the switch on the router. Never seen it before, just throwing some guesses out there. Dumb switches have no spanning tree protection in them so connecting two ports together (even indirectly) will crash your network, including switches upstream of that switch.

 

[newnews]

It is entirely possible that it isn't actually the PCs, but the process of unplugging and replugging (perhaps them renewing their DHCP lease, sending ARP requests, etc) somehow "wakes up" the router. Make sure you're not causing a loop of some sort, do the PCs also have a WIFI card in them or some other way of connecting between each other? There is some possibility that when they go to sleep, they're bridging all their connections or something causing a loop and drowning out your switch and the switch on the router. Never seen it before, just throwing some guesses out there. Dumb switches have no spanning tree protection in them so connecting two ports together (even indirectly) will crash your network, including switches upstream of that switch.

If the device is not waken up, unplug the cable will make the network normal, and re-pluging cable will make the network down again. As soon as the device is online, no issue at all.

 

[dlandiss]

I recall some models of home pc -- was it Lenovo? -- that had a chancy network port that would crash when the BIOS was set to certain power configurations or updated. It would take down everything on that network. The long-term solution was to ignore the built-in port and buy a cheap network card.

 

[drinkingbird]

If the device is not waken up, unplug the cable will make the network normal, and re-pluging cable will make the network down again. As soon as the device is online, no issue at all.

Only thing I can think is somehow the PC is bridging the TX and RX together when asleep (occasionally) and causing a loop. You could try toying with some BIOS power settings but sounds like you've already tried disabling/unchecking power management for the NIC in windows? If so the next poster may be correct and you just have to toss a different NIC in the PCs. Are they both the same brand and/or same onboard NIC by chance?

If so you could try searching that manufacturer's forums/support and see if any solution has been found.

 

[newnews]

Sorry I have to correct some information I provided. When I created the inquiry, the problem was not currently happening, so I wrote based on my memory. Apparently, there was some incorrect memory. The problem re-appeared after I wrote the post, the fact is it happens as soon as I shutdown(not sleep) the laptop. It is Lenovo P15 laptop with TB3 USB ultradock. The ethernet cable is connected to the dock.

I decided to switch to Raspberry PI 4B as my main router with OpenWRT, turn original router RT-AC68U to AP mode only. Haven't seen the problem so far

 

[drinkingbird]

Sorry I have to correct some information I provided. When I created the inquiry, the problem was not currently happening, so I wrote based on my memory. Apparently, there was some incorrect memory. The problem re-appeared after I wrote the post, the fact is it happens as soon as I shutdown the laptop. It is Lenovo P15 laptop with TB3 USB ultradock. The ethernet cable is connected to the dock.

I decided to switch to Raspberry PI 4B as my main router with OpenWRT, turn original router RT-AC68U to AP mode only. Haven't seen the problem so far

Odd. If putting the laptop to sleep does cause it to bridge TX and RX maybe your new setup (I'm assuming there is a switch in the path between the laptop and raspberry pi) is somehow dealing with/ignoring that better than the Asus was. I'm just guessing that is what the issue was, but can't really think of anything else that would cause it, unless that dock NIC somehow starts flooding out traffic when it goes to sleep, but seems unlikely if the laptop is asleep.

Did you ever try updating the drivers for the USB dock? Or possibly the bios in the laptop to update the Thunderbolt/USB-C firmware (or there may be a separate firmware file for it but I believe Lenovo bundles it with the BIOS, that's how my work laptop is).

 

[DJones]

Hello,

I am using Asus RT-AC68U with 386_7.2 firmware. I experienced strange but very annoying issue. Sometimes all my devices(computers/phones,etc.) lost the internet connection and cannot get ip from the router. I also cannot login to router from the computer with static ip address(I use static ip address for desktop PCs). Cannot ping the router as well. After spending some time to troubleshoot, I found the problem is on one computer that went on sleep. If I disconnect the ethernet cable from it, the home network restored, everything works again. I turned on that computer, connect back the cable, no issue at all. I then put it to sleep, the home network is still working fine.

Some weeks later, the same issue occurred again but causing by another computer. Same method(disconnect ethernet cable, turn on computer and reconnect the cable back) to solve the network outage.

It seems a random issue but it all happened on computers with wired ethernet connection. The computer is either at sleep, off, or non-responsive state when it is causing network issue.

It happened on previous version of merlin firmware as well.

I don't understand why a single device could cause entire network problem when there is no physical issue i.e. wire short-circuit/grounded/voltage drop/network adapter failure. To me it is more like software issue because Asus router stop assigning IP addresses.

Any advice? Thanks

My only advice make sure Fast leave isn’t turned on in the router. Fast leave enabled caused me disconnection issues over wired lan. That’s basically the only trouble I’ve had using Ethernet.

 

[newnews]

Odd. If putting the laptop to sleep does cause it to bridge TX and RX maybe your new setup (I'm assuming there is a switch in the path between the laptop and raspberry pi) is somehow dealing with/ignoring that better than the Asus was. I'm just guessing that is what the issue was, but can't really think of anything else that would cause it, unless that dock NIC somehow starts flooding out traffic when it goes to sleep, but seems unlikely if the laptop is asleep.

Did you ever try updating the drivers for the USB dock? Or possibly the bios in the laptop to update the Thunderbolt/USB-C firmware (or there may be a separate firmware file for it but I believe Lenovo bundles it with the BIOS, that's how my work laptop is).

Sorry I did not make myself clear. The laptop is actually shutdown, not sleep. BIOS and dock firmware are all up to date