LAN Port changing to 100mbps

[Rhyan04]

Hi everyone,

I am having an issue with my new Vodafone router which is absolutely driving me crazy, we have the 900mbps full fibre connection which seems to be working great, apart from the weird issue in which the router keeps on changing the port speed from 1 gbps (which my entire wired network in my home supports, every single ethernet cable connected is CAT7, all switches are gigabit, and every PC that I have wired in supports 2.5 gigabit ethernet) yet for some reason, the router keeps on changing to 100mbps for seemingly no reason, the only fix I have found is to disconnect the ethernet cable from either the switch and then replug it, or from the router and replug it, no software fixes or any tinkering with the control panel has worked, was just wondering if anyone has any insight into what this could be.

TIA

[CrimsonLiar]

Try both a different cable and a different port on the switch.  In the last year I've had a couple of cables go bad (god knows how old they were) and an 8-port gigabit switch started to head south!

[Rhyan04]

I did think it could be something like this, but even after trying a few CAT 5E cables etc, I still get the same issue, it stays at 1GBPS on the port from the router for a while, working fine, then all of a sudden the router then locks the port down to 100mbps again, I'm starting to think it's a faulty router and I will have to talk to vodafone about it.

[Jayach]

Is this happening on multiple ports? How many ports on the router are in use?

[Rhyan04]

Hi, yes, this happens across all the ports, I only have 1 port populated at any given time which is then connected to an 8 port gigabit switch, this has 2 devices connected to it, both are PC’s that have 2.5 gigabit Ethernet.

[Cynric]

@Rhyan04 Are you doing anything in particular when the ethernet downgrades?  I'm wondering whether it's the switch failing to interface the 2.5 lines. Can you tell if the PC ports are negotiable and stepping down to 1 Gbps or staying fixed at 2.5?

[Rhyan04]

The switch that the PC‘s are connected to maxes at 1gbps, so I ofc don’t expect it a 2,5gbps line to the PC’s, as far as I’m aware, no I’m not doing anything in particular, I just randomly start a download one day and the speed is about a tenth of what it should be, it’s really weird.

[Cynric]

@Rhyan04 Can you connect directly from the router to the PC please?

[Jayach]

If it's happening on multiple ports on the router, I doubt it's a fault at that end, Have you tried in a different port on the switch?

[Rhyan04 · Accepted solution]

Okay, so I have finally managed to fix this issue, and it is weird.

Before creating this post I had completed a factory reset on the router and I was still getting the issue. However, there was a firmware update released recently which I put onto the router, but this alone did not cure the issue, I then did a factory reset after the router firmware was updated and it has now been going for 4 weeks without issue so I believe the issue to be solved, thanks to everyone who offered help, much appreciated, have a great day.