Recommendation : new DSL router or chaining to existing


Sorry for opening a new topic, but I searched and my question is slightly different from older thread.
I'm in the USA, having ADSL2 service (Sonic/AT&T) and currently using the Pace 4111n and looking to try OpenWRT.

The conventional wisdom is to put the existing DSL router in bridge mode and use a new non-DSL router downstream. There are a few reasons I'm reluctant to do that :

  1. This adds buffers in the path - i.e. more buffebloat.
  2. The Pace 4111n seems to have micro latency issues, where it stops forwarding downstream packets for a few dozen ms.
  3. Lack of security updates for the Pace 4111n.

The downside of using a new DSL router seems to be :
4) Most DSL router are old, so less powerful hardware
5) Less choice for WiFi support, harder to get 5GHz
6) They tend to be discontinued and harder to find
7) OpenWRT support for them may not be as good

In particular, it seems that the most promising DSL routers are the Netgear DGN3500 and BT Home Hub 5 Type A. A few questions about it :
8) For DGN3500, how do I know if I'm purchasing a A or B model (as B is not supported and I need ADSL) ?
9) How do I know if the BT Hub 5 I'm purchasing is type A or type B ?
10) Any issue buying the BT Hub 5 for use in the USA ? Like power supply ?

Thanks in advance !


You haven't explicitly mentioned it, but ADSL can at most have a throughput of 24 MBit/s (in practice 16-20 MBit/s will be the most), that's easily handled by more current (VDSL capable) devices. If you however need a VDSL capable device (25-100 MBit/s), the situation changes.

Check the pictures/ ask the seller, there's no other way to be sure. If you'd be in Europe, you might be able to take a gamble (if the situation is not 100% explicit), but shipping costs from the UK to the US exclude that option; if you want to be really sure (and not go through the hassle of doing the initial flashing from OEM to OpenWrt), get a device pre-flashed with OpenWrt (they're more expensive, but still less than the shipping costs to the US would be).

You won't be able to use the original power supply, it's rated for 230 volts only (and comes with the British type G/ BS 1363 plug). So you will have to supply your own PSU providing 12 VDC/ ≥1.5A (slightly less common barrel plug (5.5mm/ 2.5mm, 3.0mm or 3.3mm(? it's hard to measure) and 12mm deep, + on the inner prong). Be aware that the BT Home Hub 5 Type A does not have a FCC certification (as it's only distributed in the UK and only needs a CE certification for ETSI compliance), which might get you in trouble with customs when importing it to the US (and is technically illegal to operate in North America!); technically the device should conform to FCC requirements if configured for US regdom.

The DGN3500 comes with a much older/ slower SOC (ARX168, which is less common among OpenWrt developers and regular contributors), aside from not poviding 5 GHz support in the first place. Personally I wouldn't consider this device at all and only choose between Lantiq vr9/ VRX2xx devices, finding one with good specifications and reliable (dual-band) wifi is indeed quite hard - especially in the US. If you can get your hands on a BT Home Hub Type A, this is really the top end OpenWrt compatible lantiq device to get (the initial flashing is not for the faint of heart, so check the procedure beforehand or buy a pre-flashed device).

Personally I think you're overestimating the impact of an external/ dedicated xDSL modem (especially for something as slow as ADSL) a bit, yes it does have a slight static impact on your ping times, but within reason.

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Yes, true, but it's about future proofing with OpenWRT deprecating less powerful configuration. And it might help Ethernet<->WiFi traffic.

Is there any obvious difference from pictures ?

Thanks for the idea !

Thanks for the info.

Shame on me to have forgotten that :frowning:

Oh ! I was looking only under ADSL, from your comment I would assume that all VDSL devices can also do ADSL and that I should pick from that. Very useful.

Ok, so maybe I need a recommendation for a DSL modem that does not include all the router baggage, that should be better than the Pace in bridged mode.

Thanks a lot for all the useful information !


The BT Home Hub 5 Type A comes with pretty much the perfect wireless hardware (3x3 802.11ac/ wave1) you could get in this device class.

In terms of WAN routing it can to VDSL2+vectoring/ profile 17a at up to ~85 MBit/s without software flow-offloading and up to ~115 MBit/s with software flow-offloading enabled. In other words, more than plenty for a ADSL link. Compared to more contemporary routers (and thinking about cable or ftth) it's not the fastest hardware, but it can realistically serve a 100/40 MBit/s VDSL2+vectoring connection (without SQM), for ADSL you have lots of headroom to play with.

It's written on the type label on the bottom of the device, but many sellers don't include pictures of that.

Yes, but…
VDSL is pretty much the same around the world, but ADSL comes in different varieties (Annex A or B; B is the norm in Germany, A pretty much everywhere else around the world), so you need to get a device supporting your ADSL Annex. For most lantiq devices (almost all I know), the annex is chosen at production time, by the selection of the corresponding bootstrap resistors on the PCB and choosing a matching bandfilter, in practice you can't change this afterwards. The BT Home Hub 5 Type A is Annex A.

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How about a Netgear DM200 ?

The US model is called 'DM200-100US'. It supports bridge mode.
Some used examples cost from USD18 + shipping on eBay.

Note the DM200 only has a single ethernet LAN port. Although you could put OpenWrt on it and configure it for bridge mode, I don't know if anyone has ever succeeded in being able to configure it such that you can use the single port to manage the modem AND for internet access. Search the forum for past attempts.


If the modem is in bridge mode and you use proper traffic shaping on the main router, you will rarely/never experience bufferbloat from the modem.

That might/might not be different in bridge mode.

Which for a bridged modem will not matter much, your packets are snoopable over the internet already, so if you are concerned about this, think about encryption.

Ask the seller, on my BTHH5A there is a sticker at the bottom giving all the units passwords (which see to be individualized by unit) as well as the router type, no ideal about type B models (though I assume them to be the similar, a quick e-bay search confirmed for both there is a sticker at the bottom giving the type).
The BTHH5 can be flashed and operated with OpenWrt itself (I run mine as bridged modem with luci as management interface). The BTHH5B can not, so if you buy a unit already flashed to OpenWrt you can be sure that it is of type A (and that is what I did, as getting an already flashed unit was cheaper than getting a stock one and a soldering iron :wink: ).

In bridged mode, I can push 90-100 Mbps over a vectored 100/40 VDSL2 link (under OpenWrt 19.07-rc2). I initially tried to make this my main router, but at least on a 50/10 and later a 100/40 this unit already is pretty much maxed out with just routing/bridging DSL traffic. So after trying the whole nine yards, NAT, firewall, SQM traffic shaping and wifi, I realized that this unit was not powerful enough and relegated it to do duty as dedicated bridged DSL-to-ethernet "modem" and I am relative happy with it. No idea about the quality of the ADSL part though (being in Germany the Annex A Adsl part is incompatible with the incumbents Annex B/J).

the fact that it's pre flashed means it's easy and reliable to know it can be flashed... but if I bought a pre flashed anything, the first thing I'd do would be to flash the latest openwrt over the existing image to be sure I had a secure and unmodified version. then I'd proceed to configuring etc

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I must admit I'm chickening out on the BT Home Hub 5, as I feel I now have a better options. I'll keep it as a backup if my other stuff does not pan out.

Thanks again, I'm getting an education :wink:


Good suggestion. I now have a DM200 and a WRT3200ACM in order and my wallet feels lighter.

That would be the idea. Thanks !


Thanks, I think I will go down the chaining route DSL-modem + WiFi router.

In theory, reducing the load would decrease CPU scheduling, but I decided to order a new DSL modem.

I think the worries about snooping are overblown, I'm worried about penetration. Any magic login on that device ?

I'll keep that in mind, thanks !


Yes, for sure ! Thanks !


A device in bridge mode doesn't have a public address that can receive packets right? so It's hard to penetrate a thing that isn't listening for packets...

Of course, there's always some way to get access to its config page or whatever, but usually that requires sending packets from the LAN, which means you have to compromise a LAN device first... so then you're already screwed.

Also, you can include replies to multiple people in one post... just quote the bits you are replying to... one great thing about discourse is that it lets you edit your messages, and aggregate them into a single message so the threads are easier to follow.

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In the bridged-modem configuration the modem is outside of your own firewall, sure it might serve as a base station to attack your router from by close, but to do that the attacker first needs to "jump" from the bridged interfaces to the modem OS itself.

After using BTH5 for many years I was looking to move onto the DM200 "single can" unit though I recently found it's end of life which makes it more difficult to acquire

The shape of the Ethernet ports and the xDSL port is slightly different, or at least that's what I observed.

You can check on ebay some of the devices where the seller says it is Type A or B, and you will come to know the difference. Basically for Type A, the LAN ports have tiny little holes either side of the bottom of it, what I presumed to be for LED (though they don't actually work, in OpenWrt at least, not sure about the stock firmware). Type B doesn't have those holes.

The other difference is the shake off the xDSL; for Type A the RJ11 socket looks a bit longer than the RJ45, for to a groove at the bottom, while in Type B it had the same height as the RJ45 sockets.

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