Business 4G Assure - Own Router or Bridge?

Hi,

Have got BT Business Infinity on 300/50 GFast.
The 4G assure dongle came in a separate box, which has never been opened, and the BT Business Hub was switched off once the OpenReach technician had left to be replaced with the GFast modem plugged into my own router instead.

Having had an annoying temporary outage for a while at a particularly inconvenient moment, I've now decided that a failover would be a good thing. So...

1. Can the SIM from the 4G assure dongle be extracted and stuck in a separate 4G Ethernet modem for my own router to failover between? Or is it locked to only work with the BT router?
2. If the dongle only works with the BT router, can the BT router be put in a Bridge Mode, with the GFast modem plugged back into the BT router, and then the the Bridge output from the BT router then goes into the WAN of my own router which then doesn't know the difference between that and today's setup where it has the GFast modem directly plugged in?
3. When it's doing failover, how quick and how sticky is the BT router? Does it wait for a 10 minute outage, or would dropping ping for 1 minute trigger it? And how quickly does it come back to DSL once it's back online?
4. Whilst the running on the 4G assure, do I keep the same static IP address? Or does it temporarily have another IP address until the DSL comes back?

Does anyone have any experience of using it generally?

Thanks!

Edited by Westyfield2 (Sun 22-Nov-20 21:38:58)

1. The BT SIM only works in the 4G Assure dongle - I have not heard of success elsewhere.

2. Your terminology is rather confusing - why would you want to put a router in bridge mmode? And where would the modem be?

3. The switch to 4g is within seconds and it remains there iuntil DSL is restored and seen to be stable for, I believe, 10 minutes.

4. Yes you retain the same static IP

The business hub can do static routing so it would be possible to avoid double-NAT if that was your concern.

I have the BT assure dongle working connected to a Draytek router - I was testing failover today and it works great.

You need to use the DHCP option rather than PPP. The network ID is 'everywhere' which is EE's ID No CHAP ID or password is needed. MTU 1380 - don't know if this could be changed - I just copied the number from some obscure site on the internet. I have not had time to play other than to prove it works. I just use the horrible business router in bridge mode - which does mean obtaining your credentials for PPPoE because unlike the business router, connection is not 'zerotouch' using a 3rd party router!

Cheers

Kevin