Using a BT Business Smart Hub 2 with BT Residential Broadband

[willowen100]

I have a residential BT broadband connection and I'm currently using the BT Smart Hub 2 router. I've been told that I'll be receiving Digital Voice very soon and will need to use my BT Smart Hub 2 router to be able use their new DECT phones.

To cut a long story short, I have a lot of network gear and tech I would like to isolate using DMZs/VLANs and therefore I need to able to carry on using my third-party hardware. This has left me no choice but to place my other hardware behind the BT router which of course can cause issues with double NAT, public IP address detection for DDNS etc.

Now I was thinking about going to BT Business broadband to make the most of the BT Business Smart Hub 2's 'modem only' mode that would allow me to use my third-party gear to handle routing, firewall DNS etc.

"When you enable Bridge mode, your hub light will turn orange, your Hub will act as a modem only. This will disable any router features, such as NAT, DHCP, DNS and LTE mobile connections."

https://btbusiness.custhelp.com/app/categories/guide/a_id/54889/view/54858/c/5559/

I got in contact with BT Business and BT Residential and they said there wouldn't be any cancellation cost as I'm moving broadband providers internally. There is even a department that deal with residential to business migrations who were able to answer most of my questions and provide details. Sadly my line doesn't support their business fibre connection yet.

They did suggest I could try looking for a second-hand BT Business Smart Hub 2 on eBay or a similar selling website. I was wondering if anyone here is able to clarify that I could use the business hub with a residential line and make most of the 'modem only' feature.

[licquorice]

Yes you can use a BT business hub on a residential line to make use of the bridge mode, however, I'm not sure that it will have the Digital Voice capability of the residential hub.

[willowen100]

Looking at the specifications on the BT Business direct site for the BT Business Smart Hub 2 found here it does say

"BT Smart Hub 2 comes with 2 DECT antennas and integrated support for Ultrafast broadband (G.Fast and FTTH) as well as Complete Wi-Fi compatibility."

On the BT Business Broadband packages website it does say it includes a Smart Hub and Digital phone line. I think the only difference is the firmware and the Smart Hub 2's are hardware wise identical. It's a real shame the 'modem only' mode isn't available for the residential Smart Hub 2's...

[licquorice]

Hmm,  even if it is DV compatible, I'm not sure it would be when in bridge mode as the IP layer won't be accessible.

[Keith_Beddoe]

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@licquorice wrote:

Hmm,  even if it is DV compatible, I'm not sure it would be when in bridge mode as the IP layer won't be accessible.

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Bridging only means that the public IP address appears on the interface, and there is no NAT taking place, just like a modem. There is still an IP path to the gateway, so it may still work.

[licquorice]

Can't see how the IP layer will be accessible, surely in bridge mode the IP layer is just passed through, the public IP address only appears on the router WAN port. A modem can't see the IP layer.

[Keith_Beddoe]

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@licquorice wrote:

Can't see how the IP layer will be accessible, surely in bridge mode the IP layer is just passed through, the public IP address only appears on the router WAN port. A modem can't see the IP layer.

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To be honest, I am not sure, as TCP/IP is something I never got involved with, X25 was my specialism, a much more robust communications protocol, always activity, even on disconnected interfaces.

The Smart Hub would still be able to "see" the network and  the ATM layer, which I suspect that DV uses, as that is the only way the priority tagging can be done. It was certainly the case with Broadband Talk, as it was possible to view the config on the early Home Hub 1s.

Thinks of course, may have moved on from there.

[licquorice]

It won't, there is no ATM  and DV is VOIP in any case. In bridge mode the hub is acting purely as a modem, converting DSL to Ethernet, all the higher layers are dealt with the router.

[Keith_Beddoe]

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@licquorice wrote:

It won't, there is no ATM  and DV is VOIP in any case. In bridge mode the hub is acting purely as a modem, converting DSL to Ethernet, all the higher layers are dealt with the router.

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So the ATM layer is no longer used, ATM carried over the SDH network was the "in" thing at the time I was working, but that was on the old DSLAMs. I suppose its now optical all of the way into the SDH network. Anyway, the only way to see if DV works, is to try a business hub.

[willowen100]

My DV line activates tomorrow which is exciting. I've ordered a business hub off eBay so I will post back here once it's arrived and connected.