Inconsistent Network Speeds over Ethernet

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Inconsistent Network Speeds over Ethernet
Inconsistent Network Speeds over Ethernet
2021-01-12 12:03:38
Model: Deco M9 Plus  
Hardware Version: V2
Firmware Version:

Hi,

 

I'm having intermittent network issues that I am having no success in troubleshooting myself.

 

I am using a mixture of TP Link Gigabit Switched and Deco M9 Plus in my network. 

 

The PC and Laptop and Unraid Server will suddenly drop from a Gigabit connection to 100Mbps, sometimes even lower. Resetting the 8 port switch (i.e. disconnecting and reconnecting the power) fixes the issue immediately, but the problem will seemingly return at a random time.

 

I've checked all my socket terminations, all of the wiring (seemingly no degradation), I've updated the firmware on all of the Deco M9 Plus v2s (using the updater tool).

 

All of my switches are unmanaged. I have ordered some managed ones, to see if that can help further troubleshoot the issue.

 

Can this be an issue with the switch? Is there anything wrong in my network layout? I know you're not supposed to daisy chain more than 3 switches, but can you get issues with just 3?

 

Would appreciate any help as this is driving me nuts.

 

Regards,

 

Jamie

 

 

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Re:Inconsistent Network Speeds over Ethernet
2021-01-12 14:36:33

@jamiewgrant 

 

My quick question would be that when you mention the speed dropping to 100, is this the NIC card reconnects at 100 or does the througput drop to that?

 

If its the NIC card try forcing 1000 rather than autodetecting, if its throughput then you have another problem

 

 

 

My concern is that everything in Yellow is running off one 1GB port in reality, namely the trunk marked in RED

 

3 DECO devices, 4 LAN and however many wifi is a real bottleneck on that 1GB port.    If the 16 and 5 ports support 2.5 / 5 or 10GB then that would be a good idea, if not i would consider that. 

 

My next course of action would be iperf3 tests at the following points.. test this when full speed and speed drops at the following points and compare

 

Please excuse the paint scribbles :)   X to X    Y to Y and  Z  to Z   get a baseline, then when speed is crap rerun the iperf3 test using a laptop straight to socket/patch or switch.. dont use WiFi..    gut feeling is X to X will stay same and other 2 drop..

 

This is probably your best course of action to investigate this.  If new switches is a possibility, check this first and look to 2.5GB ports on teh new stuff coming out.  It will run ok on 5e also

 

 

 

 

 

 

 

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Re:Inconsistent Network Speeds over Ethernet
2021-01-12 15:56:04

@Philbert thanks for the suggestions.

 

The NIC negotiated speed doesn't change on any of the three affected devices. Stays at 1Gbps. So it's the throughput that drops to 100Mbps.

 

I agree it's a bottleneck on that one socket, I've been thinking about upgrading it, but I'm not sure it would account for an intermittent problem - which is immediately fixed by resetting a switch. I've also tried running single devices through the switch and it has the same issue.

 

I have to admit to being a complete n00b when it comes to networking. Apologies. Is the tool you described easy enough to pick up and learn?

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Re:Inconsistent Network Speeds over Ethernet
2021-01-12 16:42:49

@jamiewgrant 

 

Yeah the tool is pretty easy to use.  Just download the files for IPERF3 and place on 2x devices connected to the switches mentioned, this will flood the connection for ~30secs and give you the result in mbps.   Ideally 2x laptops or desktops with at least 1GB cards.  One device will be a server other client, run the test and get average then swop roles round

 

To do this open command prmpt and run the following commands

 

on device to be server

iperf3 -s

 

on the client device 

iperf3 –c x.x.x.x –w 2m –t 30s –i 1s

 

x.x.x.x being the IP of the server..   as said do it both ways and record results.   test using   X  Y  and Z mentioned earlier

 

this will give you the actual throughput on the wire, get a baseline and run it again once the issue happens

 

upload the results for us to consider :)

 

 

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