Ethernet connection drops for a few seconds

[ashh]

I had full fibre installed about a month ago and I've been having issues with the connection dropping pretty much at least once a day. It's a wired connection and these are the messages I see in the event log:

03:20:02, 14 Nov.
A device connected to Ethernet port 3
03:20:02, 14 Nov.
Wire Lan Port 3 up, Speed 1000 Mbps
03:20:00, 14 Nov.
A device disconnected from Ethernet port 3
03:20:00, 14 Nov.
Wire Lan Port 3 down, Speed 10 Mbps
03:20:00, 14 Nov.
DHCP device Disconnected: 192.168.1.156, f0:2f:74:54:a3:b6, PC
03:19:59, 14 Nov.
LAN [DEL] ARP 192.168.1.156 with f0:2f:74:54:a3:b6 from br0

In this particular instance it was only disconnected for a few seconds although it can sometimes be slightly longer, but not usually more than a minute. It's really annoying because it can cause me to get disconnected from things and often lose progress.

I've tried both using a different ethernet cable and port on the Smart Hub 2 and neither helped. Does anyone know what could cause this and how to fix it? Thanks.

[Keith_Beddoe · Accepted solution]

@ashh 

Welcome to this user forum.

It will be an issue with auto-negotiation, and slight temperature changes can cause timing differences and corrupt the Ethernet Link Pulse. See https://en.wikipedia.org/wiki/Duplex_mismatch

This is why you are seeing different connections speeds.

If you fit an Ethernet switch between a LAN port on the home hub, and the LAN port on your computer/network  the problem should stop, as the switch will match the two rates.

Like this one https://www.tp-link.com/uk/business-networking/litewave-switch/ls1005g/

You would only use two of the ports, and it would give three extra ones if you needed them.

[ashh]

Huh, never heard of that before. To be clear, it typically only happens once per day for like 10 seconds, it's not a situation where I'm constantly getting disconnected over and over.

I can order a switch though and test it out if you believe that to be the issue.

[Keith_Beddoe]

This issue has been reported before, and the addition of an Ethernet switch has cured the problem. You also need to make sure you use fully wired Ethernet cables in order to support 1Gb speeds.

Another example where it was causing the home hub to restart.

https://community.bt.com/t5/BT-Devices/BT-Smarthub-2-reboots-once-a-day/m-p/2205344#M25782

[ashh]

Thanks Keith, that thread does appear to be the exact issue after comparing his technical log to mine. I've ordered the switch you linked so will report back after I've had a chance to monitor it.

[ashh]

Accepted as solution. Been about a week without the issue since adding in the switch so thank you very much!

[Keith_Beddoe]

@ashh 

Excellent 🙂

[DavidM]

Thanks for letting us know this is sorted @ashh and thanks to @Keith_Beddoe for the help.

Cheers

David