Initial thoughts are:
1. On a full FTTP connection, the actual fibre speed should be much closer to 300 Mbps down and 50 Mbps up at directly connected at the router or connected via a wired gigabit capable switch.
2. The 100m Cat5e connection sounds problematic. If the cabling is 'good' there should be absolutely no drop in speed whether the link is 0.5m or 100m long.
Now by rights (although it is seldom to never done in a residential environment) - all fixed data cabling should really be performance tested to make sure it will support whatever services you want to run over it. Most people don't bother or their installers (themselves or their sparky) simply don't have accesss to the necessary test tools (like a Fluke DSX) to do so. But it really is the only way to verify if the cabling meets the actually Category performance limits.
Otherwise rather than testing from ‘the bottom up' you will need to try less ideal but alternate methods testing from ‘top down’ to try and determine if you have a cabling fault...
- Can you check and try with another port on the switch?
- If the switch is managed, can you log in and check the port stats; receive and transmit packet errors are never a good sign, also port 'flapping' or speed re-negotiations can indicate an underlying problem?
- If you place another switch, so a switch at both ends of the long link, does that improve matters?
- you could run a local speed test across your network to check. Various tools exist - I've used TamoSoft Throughput Test and LAN Speed Test from TotuSoft in the past successfully.
Edited by Pheasant (Wed 07-Apr-21 19:59:35)