FTTP Mode and the LAN/WAN Ethernet Port 4 - potential network disruption?

[huntajon]

Whilst troubleshooting some network issues, I noticed that in our SmartHub 2  settings the "FTTP Mode" was switched on.  I don't know if it has always been defaulted to on, or if it was switched on by a firmware update at some point, but for whatever recently it was currently on, and it shouldn't be. 

Our connection is VDSL/FTTC, so FTTP should be off.   I've read on other threads (e.g.: See other question thread. )  That there's no risk to turning it on or off, when you're meant to be in FTTC mode.  (obviously if you are meant to be in FTTP mode and you turned it off, then you would lose your connection completely). 

My question is, does anyone know of, or could think of, reasons why having an operating FTTC/VDSL smart hub with "FTTP mode" incorrectly switched on, might contribute to potential network issues?  Particularly if a device were plugged into the WAN/4th port on the hub, whilst this mode was incorrectly switched on?

The internet connection has always worked,  and I suspect the "FTTP mode" has always been on, but with nothing plugged into that ethernet port.  At some point a network cable was connected to Port 4 and at the other end of the cable is a BT wifi disc.  Did connecting this device coincide with the network issues?  I can't exactly say as I'm not sure when it was connected or switched on.  The problem we've had is intermittent problems where some websites fail to load as quickly as expected, or time out, then reload instantly when refreshed.  Annoying but not a big issue.   This however also seemed to affect certain web hosted VPN services and internet security protocols used by our employers.   VPNs and Remote desktop applications using the web services would regularly drop out, but the hub internet connection wasn't seen to be disconnecting (you know about it when that happens as it takes several minutes to re-establish).  In all my troubleshooting I was leaning towards DNS issues, or routing issues, and considering replacing some of the older switches on our network that I feared might be causing loops. 

Since turning off the "FTTP mode" this morning everything has been stable, no drop outs.  

Could it be as simple as that? 

Could having "FTTP Mode" switched on, whilst also operating in conventional VDSL/FTTC mode, mean that signals received on Port 4, were causing the hub to drop other connections and try and establish a connection via that port? Then fall back when that failed?   Interested to know thoughts or if anyone has similar experiences with this mode and the corresponding ethernet port. 

[naylor2006]

Having Port 4 in FTTP mode would on the face of it cause issues, but maybe only when something is connected to it. The router would be expecting a WAN connection there which should result in configuration changes, in addition the router should remove the Eth4 port from the Switch, so any LAN traffic would not be there, as ports 1-4 act as a switch when there is no FTTP enabled.

With that said its an ISP router, it might have more fail safes built in, and not behave like a 'normal' one, IE if it detects a VDSL service then it wont be over ridden with some FTTP config if the physical connection is not there. Its interesting because when the SH2 is in FTTP mode and you connect a LAN device to the WAN port and not a WAN connection from the ONT, the light just goes orange on the hub. I tested this a while back because when people use their BT hub as an AP they get annoyed by the constant flashing purple light, this can be avoided by just connecting a short patch lead from ports 1,2 or 3 straight into 4, the FTTP connection errors out and the light goes solid orange.

Anyway, if you dont have FTTP do not enable that port as such so it remains part of switch and you can then connect other local devices to it. Curious what your lights are doing during these issues.

I know the other question was how did it get switched on, maybe it always was, I dunno.