I have just recently discovered Ethernet cable issue can be extremely tricky to identify. One would think defective Ethernet cable will give overall low speed or no speed and when tested there is an issue of continuity. However, I have just learned the issue can show up as a puzzling, peculiar result such as distance dependent asymmetric up/down speed. Today, I provide a real life example/struggle I am going through at the time of this writing.
Background
Recently, I have been playing with my network setup and getting to the point where I am fairly happy with my Wi-Fi setup. As a next step/plan, I have started to look into 10G network. I have had couple devices that support 10Gbps speed, Qnap NAS and Mac mini, but I had never had a chance to test them due to the placement of these devices and had not had much interest before.
With settling Wi-Fi setup, my interest to 10G has suddenly erupted. I have just purchased a thunderbolt 3 to 10Gbps Ethernet adapter. This would allow me to test the 10G network speed using my MacBook Pro 2015 laptop in different rooms and ensure I have the supporting backbone needed for the future upgrade.
Setup
My current network is setup as above. The Qnap NAS (TVS-472XT) is capable of 10Gbps communication via its 10G RJ45 port.
*This item is no longer available on Amazon as I believe now it has been replaced by TVS-473e.
USW Pro 24 Gen 2 switch by Ubiquiti has two SFP+ ports supporting 10G. For those of you unfamiliar with SFP+ port, it is a special port often used for backbone connection of network devices i.e. switches together. There are adapters one can buy to make these ports into normal ethernet port (RJ45).
I have also had a multi-gigabit capable switch by Netgear MS510TX as part of my prior I converted my whole network into UniFi setup.
This switch has 1 SFP+ and 1 RJ45 ports supporting 10Gbps. Additionally, this has 2 up to 5Gbps capable ports and 2 up to 2.5 Gbps capable ports.
In order to test 10G speed the whole pathway between two devices must be 10G capable. This is not possible through the internet in majority of home in the world; therefore, the test is usually conducted locally between a local area network (LAN) connected devices/computers. Wi-Fi should also be not part of the path because they are not capable of delivering 10G speed even with the latest Wi-Fi 6 protocol.
To test a throughput between two computers connected on the same network, we have a handy, standard command tool, iPerf. I have my Qnap NAS running iPerf in server mode and for the client I use MacBook Pro 2015 model which is now 10G capable by the use of LINKUP adapter. Therefore, the real network topology/setup for 10G testing looks like below.
I could technically bypass one of the switch. When I discovered there is a throughput issue, I have indeed tried this i.e. connected Patch Panel to Netgear Switch then to the Qnap NAS. However, this did not change anything; hence, I restored the real/more appropriate network setup as above.
All wired connection between points use Cat 6, unshielded ethernet cables. Short cables (blue) are patch cables i.e. under 1-3 ft. Long cables (black) connects network rack in basement storage room to different rooms in my home, usually via attic space and some even partly coursing outside. Some runs I believe are reaching over 150ft. The medium cables (red) are what most of us typically use to connect from wall jack to a device, which are usually 3-5 ft range.
Patch Panel is a device that can be thought of as a giant multiple Ethernet wall jacks in a single panel. Technically, I can connect each run of ethernet cable from home wall jack directly into the switch but that would be hard to manage/organize.
10Gbps Confirmed
The first thing I did was confirming my existing setup can indeed support 10Gbps speed. I had 9 total Ethernet lines installed in my home about a year ago using unshielded Cat 6 cable by True-cable. For the test, I used iPerf 3 with server application installed on the Qnap NAS and using command tool connected from MacBook Pro 2015.
I was able to get 9.4 Gbps both up and down in the office, a room closest to the network rack. To my surprise, I was also able to get 9.4 Gbps up and 8+ Gbps down on the longest run wire, which I estimated to be ~150ft as it has to run from one end to another of my home (80-100ft) with one floor up, basement to attic, then some distance back down.
4 More Lines for future 10G Network
As I was able to get essential 10G speed even on the longest cable run room, I have decided to add 4 more lines in my home so I would be ready to have a 10G home network setup when the time comes. All 4 runs are physically closer than the longest run I already had. So with the exact same cable I got for the first time by TrueCable, I felt very confident that 10G speed will be achieved on all 4 new spots.