Corporate style PoE switch combined with DSL router?

Hi all,

I have used a BT home hub with OpenWRT for a while and really liked it (until it had a failure and I went back to the ISP's one). I see that a lot of the devices in the list of hardware are more domestic / home routers, but I am interested in something a little more corporate / industrial.

I have a sizeable home network with several PoE devices, operating from a gigabit speed, >10 year old CISCO 24-port 19" rack network switch (with inbuilt noisy fan). The recent hike in energy prices has made me look closer at the power consumed by my network devices (PoE WAP's & CCTV), and I need to make some changes to cut our power consumption.

I am looking into replacing my router and switch for a device that can provide all the functionality in one box, hoping that reducing the number of plugged-in mains power supplies may remove some energy inefficiencies (after reading some advice from CISCO that suggested this approach was best). Also hopeful that going for a newer device may bring with it greater energy efficiency, such as a convection cooled device with no fans for starters.

I have a few raspberry Pi's in the house too for various reasons (home automation and media players) and I may want to move these over to PoE if it can be shown to give further (smaller) energy savings, by removing more mains power supply units, and loading up the single switch instead.

Is there any such combined router / switch device out there? What terminology should I be looking for? If so, has anyone managed to get one working with OpenWRT? I'm an engineer but need some advice from someone with more of a corporate / industrial networking experience.

Summary of desired specs in one device:

  • OpenWRT compatible.
  • DSL router for UK BT phone network (we are in a small village so no fibre broadband to the house yet, vague possibility of it in the far and distant future).
  • Minimum 24 Ethernet ports, more would be better - I have 40 runs of Ethernet Cat6 in the house, but not all are in use at the same time.
  • Ethernet ports: Gigabit speed, and PoE (not all need to be PoE, but at least ~15 do).
  • Fan-less, convection cooled.
  • Noted for energy efficiency compared to other similar devices.
  • Dual redundant power supply sockets is not essential as I have a UPS, but would be good for reliability.
  • No need for a fibre optic LAN connection as I will never have a run long enough round the house / garden, Cat6 suffices.

I know it's a big ask, but there may be someone out there who dabbles in this sort of kit and could advise if it's possible, and what to look out for.

Many thanks, Scott.

Don't think you're going to find a dsl PoE switch combo.

But you could get rid of some of the power supplies, by powering the devices from the PoE switch, using PoE splitters on the device side.

Thank you @frollic , yes I had considered separate PoE splitters as there are a simple addition, but Adaruit also has a nice isolated board that may fit inside an existing Raspberry Pi case:

Shame you think I won't be able to find a combined box, I was rather hopeful but as I had not yet found one online I was beginning to wonder.

Thanks, Scott.

As far as xDSL support in higher end gear is concerned, there are xDSL modems available in SFP modules (e.g. these).

There is some support in OpenWrt for Realtek chipset managed switches, including some initial support for both SFP modules and POE - though it's probably at the early adopter stage at this time (more info in the development thread).

Just as a side-note, in my experience a lot of DSL-noise/interference can be caught within the own premises, therefore it can be helpful to move the DSL modem as close to where the telco's copper wires enter the premises to keep the chance low of collection avoidable interference (ethernet is so much more robust against the RF-noise levels that make DSL unhappy it is not even funny anymore). That place however might not be the best place to position a router (or AP), which might be an argument for separating modem and router functionality.
At least for me removing ~12m of surplus internal telephony wiring (of low quality) inside my apartment cleaned up the DSL signals a lot.

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The SFP VDSL modem looks like a nice option, but I'd be careful. They are expensive and very power hungry. The spec at says 2.1 W.

Note that the default SFP slot power budget is 1 W. Many devices will be capable of providing more, but the exact specs are hard to find. I have no idea if any of the realtek devices supporte by OpenWrt support such high power devices. If they do you'll have to add this into to the device tree, as I don't think any of them have non-default power settings.

I seriously doubt there is anything to save here regardless of energy prices. Unless you can get one of these SFPs for free.

Thank you @moeller0 - in my house I have the current ISP router right at the BT master socket 5C, the server cabinet is in the garage. There is a telephone line extension using overall screened Cat6 cable (F/UTP) into the garage, routed through the house away from mains cables, and all other Ethernet cables, basically I gave it it's best shot, but the downside is the length, which is just under 20m.

A test on this front would be moving my current router to the garage extension and seeing what happens regarding hiccups.

@bmork - I like the idea of an SFP DSL modem inserted into a switch, as it does sort of answer the main question of this post, but as you say, it's an area of a few unknowns: is power consumption too high for the switch slot? As Pythonic pointed out there is not yet an off-the-shelf OpenWRT install for these devices, so I will be looking at the OEM's interface, how well documented is it and will I be able to configure it correctly?

On this front, a fanless switch I've been reading about is the CISCO Catalyst 2960L, there are a couple second hand on ebay, as I'm not forking out £2K on a new one! Does anyone else have any other fanless gigabit poe switch suggestions?

Thanks all for these ideas, it's helped a lot,
Cheers, Scott.

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By all means try that, it might work perfectly, just keep in mind if it does not that moving the modem back to the 5C and just use the cat 6 cable for attaching a bridged-modem to your router is an option.

I wonder whether that will suffice, assuming your ISP uses PPPoE, either the "switch" would need to be able to terminate PPPoE or you need to connect the "dsl-port" with a dedicated port feeding your router, (while making sure your manageable switch is secure from any shenanigans the internet might play).

It's not 'just' about the power consumption, but just as much (if not more) about the heat dissipation as well. The sfp cages are tiny, and VDSL modems run hot.

When the Turris Omnia crowd first found these SFP VDSL modems, they were (understandably) all over it, but then the problems started. Aside from power and heat, these devices aren't designed to be ISP CPEs, but to act as master-slave connection over phone cables between buildings (just like powerline or MoCA). Using them as CPE might just happen to work - or fail, depending on firmware interoperability. But given the more restricted designed use case (only having to support a peer built by the same vendor), firmware doesn't get the field testing of regular VDSL modems and is not user-upgradable in the first place.


Good points, on a reliable link it probably does not matter much, but once instability crops up, it can be helpful in diagnosing/finding problems if the DSL error counters are easily available.
Thank ${DEITY}, that fiber to the premises/home will likely replace all DSL links in Europe over the next decade(s), where SFP options are available that do neither run too hot nor require too much oomph, or where diagnostics are likely important.

I've had a Cisco WS-C3560CX-12PD-S for years. Lovely thing, with 240W PoE budget, internal power supply, two 10gig SFP+ ports, 14 1000BaseT ports, and still fanless. But as you say: These semi-professional Cisco devices are too expensive.

I can recommend the ZyXEL GS1900-10HP as a much cheaper alternative. The OEM firmware works. And it runs OpenWrt fine. The power budget is limited to 77W and it uses a large (laptop style) external power brick. But this also makes the switch very compact compared to the Cisco. No 10gig ports unfortunately, and only 10 ports in total.

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Assuming the DSL SFP acts a "bridging modem" and presents an ethernet interface to the switch (and I can't think of any other possibility making sense), then you can just trunk it to your router. Exactly like you would do if you had a DSL bridging modem connected to the router via an ethernet cable.

FWIW I am using a switch between my DSL modem and two different routers, where one of them is running PPPoE and the other DHCP/DHCPv6 IPoE. Both over the same DSL line. But that's disappearing in a few days now. Copper is dead. At least around here.

(have had fiber for 10+ years too, but kept the DSL line until now since it's conncted to a better ISP. eh, well, or an ISP I happen to work for)

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Yes, that is what I meant by:

Except, a direct link bypassing a manageable link offers less attack surface to the internet, not that it is very likely that the manageable switch can be taken over from the outside.

Lucky you! Over here it is going to take a "few" more years. I a saying that living immediately next to one of the incumbent telco's central office, so 20m of fiber-cable is all that I am lacking (plus the active parts on both ends) :wink:

No free choice of ISP over the fiber infrastructure? (Will also not happen here, except the incumbents seems willing to allow resellers on its GPON links, IMHO most likely as pro-active move to avoid being forced to do so with ex-ante regulated prices, but I digress; but in spite of signaling willingness for over a year now, no resellers have materialized yet).

Nope. It's a real mess.

That's a great recommendation thanks!

I have looked them up, their PoE versions do have fans, but they are speed controlled for efficiency, and are apparently very quiet. I presently have no need for a 10gig uplink, as we live in a small village, and priority seems to go to the big cities and towns for fibre to the property; our street box only just got Fibre a couple of years ago! Ironic as the main fibre link between two major cities has run right through us under our main road for decades!

All of our kit in the home is either 100/1000 baseT so again, gigabit speed limit round the house is fine for now (with no future-proofing).

Cheers, Scott.

The "HP" versions have PoE. And the smaller ones like the GS1900-10HP are still fanless. Made possible by the external power brick I guess.

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Interestingly I'm trying to find out which ones conform to 802.3az, their datasheets state under standard compliance quite a number of IEEE standards, including az, so do you thin they all are Energy Efficient Ethernet compliant?

Seems to be the same datasheet for all switches..

Cheers, Scott

I expect they are. They are all using the same SoC family and related PHYs.

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I tested EEE on a GS1900-10HP once under OpenWRT and it worked. The power meter I had put between the plug and the switch showed considerably less power usage once activated. Not sure the larger ones with 24 and 48 ports can do that under OpenWRT, too, because there might still be a bit to implement specifically for these devices but from their HW specs they are able to support it. Personally my experience with the OEM user interfaces were not very good when trying to enable EEE, often it was hidden in some sub-menues with little diagnostics available (both sides need to have EEE enabled).

As I did not want under any circumstances the DSL modem in or near that ancient T+T cabinet where copper enters my house I just replaced a similar in-house run with CAT5E and do get in excess of 500 Mbits over So just make sure not to use any unshielded none CAT5 in-house cabling to the DSL modem and you should be fine.