Very weird internet issues

[+Mud W1ggle Subscriber²]

Hi All,

I have a very strange issue I cant figure out right now and wanted some ideas from the internet at large...

I have a 2 gbps internet fibre connection (both directions)

I have a UDM Pro, with a couple of GB switches (also Unifi) , and an USW aggregation (Unifi) switch for the stuff using faster than GB. All are latest firmware,

I have a 2.5gbps NIC in my PC (Realtek) as well as USB-C 2.5g dongle to test with.

I can safely connect to my NAS and transfer files at 2.5gbps speed, as well as run iperf for hours on end with no issues

but if I run speedtest.net on my PC, it very quickly kills the connection, and requires me to disable and then re-enable the NIC in the PC to get network connectivity back again (does this with both the built in one and the USB diongle). Also downloading a game with Battle.net or steam will also kill the connection.

There are no event logs generated on the UDM Pro or windows/Linux when the connection is killed.

This happens on both Windows 11 and Ubuntu so it doesnt "appear" to be an OS issue.

I can happily run the speed test on the UDM Pro itself and get 2 down and 2 up

Any thoughts would be appreciated!

[Mindovermaster Global Moderator]

@BudManmight know more.

But, as far as I understand, there must be a connection issue/breakage somewhere along this line.

[+Mud W1ggle Subscriber²]

On 19/09/2024 at 15:03, Mindovermaster said:

@BudManmight know more.

But, as far as I understand, there must be a connection issue/breakage somewhere along this line.

Yeah its strange.  The NAs is sonnected to the same switch as my PC, and the router is connected to that switch too via a SPF+ cable. 

[HoochieMamma]

Try and rule out the Ethernet run and the port it's using on the switch. Does it happen if you do it on another port in the house/switch?

[+Mud W1ggle Subscriber²]

On 19/09/2024 at 16:35, HoochieMamma said:

Try and rule out the Ethernet run and the port it's using on the switch. Does it happen if you do it on another port in the house/switch?

with some extra troubleshooting this afternoon, it looks to be the USW Aggregation switch at fault.

If I run a SPF to Cat 6 converter into the router directly its fine, but when the SPF is in the USW Agg it fails when transferring high speed to the internet.

This leads me to wonder if the DAC cable connecting the UDM Pro and the USW is faulty, even if it is showing a solid 10G connection...  (its a genuine Ubiquiti one too)

It would explain why the PC to NAS works (traffic is inside the USW only)

 

 

[+Warwagon MVC]

I've had this issue on every router OS I've ran off a computer

The only solution I found is to set a cap for the max download on the wan side. So instead of 1gb I dropped it to 980. In your case try 995 

I was downloading a ubuntu ISO and they must have some good pipes because at around 130 per second the internet connection died network wide. it did recover after 1 min But after I dropped the speed slightly so the max could never be reached, the issue went away.

it would only happen downloading something that would saturate my connection. LAN wise it never happened. Only WAN traffic.

[+Mud W1ggle Subscriber²]

On 20/09/2024 at 05:44, Warwagon said:

I've had this issue on every router OS I've ran off a computer

The only solution I found is to set a cap for the max download on the wan side. So instead of 1gb I dropped it to 980. In your case try 995 

I was downloading a ubuntu ISO and they must have some good pipes because at around 130 per second the internet connection died network wide. it did recover after 1 min But after I dropped the speed slightly so the max could never be reached, the issue went away.

it would only happen downloading something that would saturate my connection. LAN wise it never happened. Only WAN traffic.

What do you mean by a Router OS you've run off a computer?  The router is a rack mount piece of kit designed for multi-gigabit connections.  It looks like the Intermediate 10G SFP+  I use for the high speed connections is at fault.

[+Warwagon MVC]

 

On 19/09/2024 at 17:18, Mud W1ggle said:

What do you mean by a Router OS you've run off a computer?  The router is a rack mount piece of kit designed for multi-gigabit connections.  It looks like the Intermediate 10G SFP+  I use for the high speed connections is at fault.

I was just talking about in my case. It happened to me running PF sense and open WRT.

[+Mud W1ggle Subscriber²]

For those interested, I figured it out!

It was having two SFP+ to RJ45 converters next to each other in the swtich, the moment I moved them apart, it all started working exactly as it should be behaving!

I can only assume some heat issue when its being pushed hard, or some form of intterference..