All WFH network 1GB except one segment is 100MB, puzzled.

[m1kta]

I have checked the ports, ethernet setting etc and all report 1GB but one segment (garden office) still reports 100MB. Do a broad band test from there and you can see it.

Is there a networking tool that will help pinpoint / find (maybe ID device) where in home network a 100MB limit exists? I have eyeballed ethernet cards, all switches and cables and all settings at 1GB full duplex but still seeing 100MB limit for that one segment, very frustrating. I seem to remember seeing something but cannot remember what it was called.

It is somewhere in the infrastrure as if move a laptop from one other the other (cable connection) the speed changes.

[carl_pearce]

Have you directly connected a device on the ethernet cable between the garden office and a known working gigabit switch?

[m1kta]

Thanks Carl, that is what is most puzzling, it reports a GB connection locally at both ends. The cable between might be suspect, I thought CAT5e or CAT6 was fine for GB over 50m. Maybe should swap to dark fiber and couple fiber converters?

I still looking for that software though, I am sure I've seen it.

BTW VM Broadband is 250MB (reports 236MB/s with a following wind so pinch of salt on those VM numbers perhaps!) so it's local networking I am really interested in.

[Adduxi · Accepted solution]

If the cable has failed, it could drop to 100mb, as this speed only needs two pairs.  1Gb needs all four pairs to work.  Both Cat 5e and Cat 6 are good for 1Gb at 100 meters distance.

[m1kta]

Tnx, making me think the cable is the culprit. As fiber and converters a lot cheaper than once were I suspect might use some multi core fiber but gonna have to pull through a conduit so might need to be SWA maybe?

[Adduxi]

Wouldn't do any harm to have in any case.  When Openreach pulled fibre to my premises from the footpath, they didn't mess around.  It was quite a lot of pulling on the outer sheath, but the inner fibre survived intact !