Question Gigabit Ethernet switch from 1Gbps to 100Mbps


Jul 21, 2019
Hello guys, my internet stays at 1gbps for about 1-2hours and then switch to 100mbps (it disconect and conect again with low speed)
I have already changed the plugs rj45 and still having the same problem...
i'm using cat5e. long cable (about 25m)
i think at some point a electrician patched the cable, maybe he connected different color pairs (?) with mixed pairs it will work for a while and then switch to 100mbps?
Should i go to the ceiling and see if he mixed the colors? sounds dangerous...
well i'll try test my computer with a good cable right next to the modem.

thank you guys!
You can buy a cheap ethernet cable tester for about $10-$15 and it will show you if the pairs are out of order. Very technically it doesn't matter what color the wires are as long as the pairs are kept correct.

These are very basic testing units they pretty much just see if you can light a led with a battery not that they can carry actual traffic. They also will not detect things like if you do something dumb and mix the wires from different pairs. Pretty much they only can tell if pin 1 hooks to pin 1 etc.
They do find the most common problems.

It is always best to run continuous cables with no splices. The splice would be ok if it is done properly. They make small splice punch down things. Doing something like twisting the wires together and taping them it not a recommended method of splicing ethernet cable. In general if done correctly the only downside to any splice is it will reduce the total distance the cable can run. You are well under 100meter limit so it should not affect you.

It is highly likely the problem is some cable issue. The only other thing it can be is a bad port which can not really be fixed. Be sure you are using quality cables. You want pure copper cable (no CCA) with wire size 22-24 (no flat or thin cables)