I know this question has already been asked a few times but I feel that my case is a little different since I've tried all the solutions provided in the other threads.
I created a small diagram to avoid any potential confusion.
So I have a cat6 cable of 80 meters. This cable has worked in the past. However, 2 years later I want to use that cable again and now it only gives me 95 mbps(tested with iperf3), it also gets recognized as a 100mbps link instead of a 1000mbps link. Image 1 provides a visual representation of how everything is laid out at this point.
- The lsa wall plug that I use: https://www.allekabels.be/netwerk-wandcontactdoos/11438/1084697/cat6-wandcontactdoos-inbouw.html
- All other ends of the cable are terminated with this rj45 connector: https://www.allekabels.be/stekker-doos-en-krimptang/188/1349725/cat6a7-modulaire-connector.html
- The type of cable I use: S/FTP - CU 250mhz
My troubleshooting steps:
- Redo the connector, router side (changed nothing)
- Redo the lsa wallplug, pc side (changed nothing)
- Test the cable with a cable tester. (all wires are working, but still only 100mbps)
- Check the entire cable for kinks (Found two kinks and cut that piece out. Connected the now 2 cables by adding an rj45 to the ends and connecting them with an ethernet extender, see the after part in the image) (solved nothing)
- Test the cable again with cable tester (all wires are working, still 100 mbps)
- Test the cable with iperf from the router to the extender (950 mbps, recognized as 1000mbps link)
- Test the cable with iperf from the extender to the PC (95 mbps, recognized as 100mbps link)
- (The previous 2 test results do not change if I do them with or without the extender included.)
- Redo the connector for the cable from the extender to the pc (nothing changes)
- Redo the lsa plug for the cable from the extender to the PC (nothing changes).
- Test again with the cable tester (all wires are working)
- Nothing changes no matter what I try.
Things I know for sure:
- The rj45 connectors support solid core cable.
- The lsa plug supports cat6.
- I use the T568B standard everywhere.
- The type of cable I'm using is S/FTP cat6.
- The cable does not run anywhere near any other cables(except where it connects to the router).
- Short distance of about 15 meters works just as it's supposed to.
- Longer distance of about 65 meters gets recognized as a 100 mbps link
- The entire cable runs inside a conduit.
What else could it be?
The only thing I can think of right now is that the signal isn't strong enough by the time It reaches the pc. So I am still planning putting a switch in the middle of the 65 meter part of the cable. However I would rather not do this since this is outdoors and I don't have a good way of protecting the switch or the not interrupted cable from the elements.
If this also does not help, would upgrading to a cat6a help? I read somewhere that cat6 Is not that reliable after about 50 meters.
PS: If you find any spelling/grammar mistakes, please let me know. I am still learning English ;)
UPDATE I fixed the issue by adding a gigabit switch in the middle. Now I have a 1000mbps link with a PC to PC transfer speed of +-870 mbps.
However, there are still a few very interesting answers which you should definitely read if you stumble upon this post in search of a solution to your ethernet problems. Especially the answers from @Zac67 and @The Unix Janitor