I am running with the latest firmware 3.9.2

With this and earlier firmware, the router starts with LAN ports at 1000Mb and after a while falls back to 100Mb. I have seen an improvement with the latest firmware where now only one or 2 ports fall back to 100Mb.

If I remove the offending plug, or restart the router remotely the port goes back to 1000Mb, and will usually stay there for days, before going down to 100Mb.

Is there a way of forcing a port to stay at 1000Mb?

What is the speed of the port of the other device? Obviously it needs to be 1Gbps, too, whereas if it's 100Mbps, then logically, there's not much that can be done about the speed.

If it's 1Gbps, then is there some kind of power-saving on on the other device? Also, how much traffic is there? If there's not much traffic between the two, there wouldn't be a point in using up power to keep the port powered at max speed.

edinburgh wrote:
What is the speed of the port of the other device? Obviously it needs to be 1Gbps, too, whereas if it's 100Mbps, then logically, there's not much that can be done about the speed.

If it's 1Gbps, then is there some kind of power-saving on on the other device? Also, how much traffic is there? If there's not much traffic between the two, there wouldn't be a point in using up power to keep the port powered at max speed.

Sorry, I didn't seem to receive notification of your post, or I would have responded earlier.

An example device attached that went down to 100Mbps is an TP EAP225. This is a V1 with the latest firmware and is a 1Gbps device. I can't see any power saving feature on this. On the Dashboard the LAN connector goes orange after a time. If I reboot the 2860, the LAN socket reverts to 1Gbps and goes green.

So, have you checked Vigor's settings: https://www.draytek.com/support/knowledge-base/5782 and possibly this: https://www.draytek.co.uk/archive/kb_vigor_throttle.html

Hardware acceleration on? (https://www.draytek.com/support/knowledge-base/6122)?

Is the cable of the appropriate grade?

Finally, if none of the above, have you reset the Vigor and tested with a minimum configuration (such as WAN only), gradually introducing other settings?