I am trying to install a 1000Mbit segment that is about 285ft long. It works perfectly fine at 100Mbits, but it won't do 1000Mbit. The testing devices (2 computers, 1 switch) have 1000Mbit ports. All ports were verified at 1000Mbits using a 175ft test cable.
I have been using iPerf3 to test the connection speeds. The 175ft test cable averages 945Mbits/sec and the 285ft cable averages only 97Mbit/sec. Both cables are cat 5e made from the same spool.
It appears that the 285ft segment cannot detect the 1000Mbit ports between the two computers, so it drops down to 100Mbits, and it clearly handles 100Mbit without any problems.
It's my understanding that 10\100\1000 all support segments up to 100meters, thus if a segment works fine at 100Mbits, why would it not work at 1000Mbits?