I need to spec a new switch for the house. This has to deal with typical network traffic between servers, workstations, etc. And, multimedia/security devices and phones.
At a minimum, I need:
- a total of ~32 ports (this can be split over two or more switches)
- 100M or better on all ports
- PoE (or PoE+) *and* capable of supplying full load on all ports!
- PTP support (boundary clocks)
- battery backup (of the switch and PSE, selectively!)
- *ideally* something at least as capable as LLDP-MED
- ("green" support would be a definite win!)
I'm having a hard time finding products (ignoring cost, for the moment) that meet all the above with the degree of "fine" configuration you would need in a home (vs. office)
Alternatively, I can use a more conventional PTP switch and add midspan injectors. But, I imagine this would be more costly, definitely add more physical *volume* and probably make the LLDP-MED-like capabilities less available.
Lastly, how practical is it to design small 4/5 port switches with these capabilities? Or, does it become unrealistic from an economic standpoint?
That's a /lot/ of ports for a home system. It's also an unusual number of ports - most switches have 5, 8, 16, or 24, then jump to 48 with a very hefty price increase.
Try to limit yourself to 24 ports, or consider using more than one switch.
If 100M is good enough, then using more than one 1G switch will also be fine.
What are you trying to run from this switch? PoE costs a lot, especially for lots of ports. Avoid it if you can.
I have never heard of a switch with a battery backup (of course, that doesn't mean they don't exist!). In most setups which are serious enough to need battery power, you've already got a professional-quality UPS. For just the switch, any cheapo UPS will do the job (and for smaller switches with external transformers and a DC power input, you could probably make one yourself). If you really need lots of PoE equipment running off the switch(es), then your UPS must be dimensioned for those devices.
No idea what that is.
Of course you are having trouble finding such a device - it's a very odd specification, and won't fit with anything realistic for the home /or/ office market.
I don't know if you mean to imply that home devices need /more/ configuration possibilities, or /less/ than office devices. But switches are either unmanaged (no configuration - basically a free-for-all on the network, though some respect QoS control) or managed (letting you control ports, filter traffic, set up VLans, etc). Modern managed switches are fairly easy to work with - you can do as little or as much as you want via a web interface. I've been happy with D-Link managed switches (in an office environment - at home, unmanaged is fine for me).
Most small are based on two routes. Many small managed switches have an SoC with a switch and a processor (often MIPS, occasionally ARM). You can't buy these SoC's as a mere mortal. But many also use switch chips
- Infineon used to have a series, but they sold that department to another company. I can't remember the name of the new owners, but I'm sure Google can find it. There you can get switch chips with 6 or 9 ports (one of which has an MII interface to connect to a microcontroller, rather than an Ethernet port). The chips can either run unmanaged, or in a fairly simple managed mode (with VLAN support, etc.). They are controlled by an SPI interface. Typical uses include small managed switches and small internet routers/gateways. It should be perfectly practical to design a system round such devices, especially if you only need a small micro to configure the switches and don't need to implement an Ethernet stack on the micro.
I currently fill a 16 port switch -- just with "processors". I can keep these off the *above* switch (i.e., they don't need PoE, PTP, etc.) though "a few" hosts will end up moving onto the new switch (because they *do* need PTP, battery backed communications and the ability to interact with the PoE devices).
The downside of more switches is basically physical space.
Yes, though not *necessary* from a bandwidth standpoint.
Most of the ports feed automation and multimedia devices:
- "control/display" panels
- pan/tilt cameras
- "network speakers"
- "network video"
- VoIP phones
It's conceptually easier to just have the switch handle power distribution than to design a midspan hack to do it.
Correct. In an *office* environment where space is not important (nor *wasted* power), you would back up *everything*. But, worst case, that would mean ~500W just for the PSE capabilities (assuming 100% efficiency).
Realistically, that's overkill. You could configure your "home" so only certain phones are active in such a situation. And, can decide that you can afford to live with one (or none?) video monitors and one set of (stereo) speakers, etc.
Likewise, you can probably afford to live without security cameras (for a short outage) -- trading each load shed for longer up-time on the remaining "critical" loads.
Essentially an in-band protocol that lets the PD's talk with the switch to more capably manage their power requirements. I.e., PoE just allows a PD to negotiate how *much* power it (might) want (class of service). And, this is done on a hardware signaling level.
The PSE would then have to commit to being able to supply *all* of that power to the PD -- even if the PD isn't really needing it
*now*. LLDP-MED lets the PD tell the PSE (in this case, the switch acting as an endpoint PSE) "I can throttle down to a standby power level of _____" -- so the PSE (switch) can shift that power to something needing it *now*.
I suspect this is what you will see being offered in the near future as PoE and multimedia become more common in the home.
Imagine a not-unreasonable scenario:
- we'll have "network speakers" installed in most of the rooms (kitchen, family, bedrooms, living)
- we'll have "network video" (displays) in pretty much the same rooms (so you can watch TV/movies in any bedroom, living room, etc.)
- you can imagine where telephones might be located...
- a "control panel" will be located in almost every room. This will provide access for audio/video controls, HVAC, security, etc. (i.e., you don't sit at a PC to interact with The House)
- "network cameras" will watch the entrances to the house (instead of the "peep holes" typically found installed through doors)
In exchange for these bits of kit, you discard the "hi-fi's" in currently found in each of these rooms as they can be replaced by audio served up from a media server (located "out of eyesight"). Likewise, discard the VCR, DVD and television tuners from each of these locations.
With PoE, you eliminate the need for supplying power *at* each node. Normally (non power fail scenario), you would probably elect to keep all the phones powered up (so you could originate a call from any of them) -- assuming you don't support a green mode (that would keep just the minimum interface operational and enable the phone to *request* power when "taken off-hook".
But, you wouldn't want to burn power (or *allocate* power!) in "network speakers" that aren't currently "playing music". Or, video clients that aren't currently "being viewed".
[analagous to shutting off the stereo/tv when not using it!]
If, for example, you sat down to watch a movie in the living room, then you would want the "network video" client in that room powered up -- along with the "network speakers" (audio clients) that are associated with it. Then, the appropriate video and audio delivered to those clients -- until you were done "watching your movie".
As above, I am more interested in the PoE management. I.e.,
*ideally*, being able to turn ports on/off (deciding how much power each is allowed to use) or operate them in a "green" mode (providing just enough power to the PD to allow it to *signal* the PSE when it would like to be "powered up" -- imagine taking a "phone" off hook and having that device signal the PSE "Hey, I need to be powered up in order to allow this user to make a phone call from this device")
[If you think about it, this *has* to be the way things will pan out in the future -- assuming the Industry isn't brain damaged!]
For PTP, the switches would need that "hardware" support. Or, tightly coupling the uC to the switch/MACs.
I don't expect this to be the most efficient way of implementing such a scheme. But, with "available technology" it may become the default way of doing so. E.g., imagine a switch designed with N SoC's in it -- each capable of monitoring and controlling the power (and traffic) to the "one" (?) port that is services...
[I have to anticipate where the switch/PSE/PTP vendors will ultimately end up. If that forces my "present day" solution to be more expensive/inefficient than a FUTURE mainstream solution, well... so be it.]
4 8-port switches are going to be physically much smaller than anything that supports 32 ports. By the time you include things like the transformers and power supplies, it's probably quite even in volume. But with multiple small switches, you can place them better and then have less cabling.
Of course, /you/ know what this all looks like in your home - I can only make wild guesses.
Do all these devices have PoE support? If not, then the effort is wasted.
I agree that PoE can be convenient - you only need one cable into the device. But it comes at a cost.
One big UPS is usually more power efficient than multiple small backup systems. But I understand what you mean about space.
Buy a mobile phone. If there is a power cut, you can still ring the electricity company. And buy a book and a candle, so that you won't need your speakers or monitors during the power failure. Either power cuts are so rare and short that it won't matter that you are disconnected for that time, or they are so common and long-lasting that UPS and battery backups won't last anyway.
There are only two things in a (normal) house that can benefit from battery backup or UPS. One is servers or NAS systems, so that they don't get unexpected power fails. The other is security systems.
OK - I am not fluent in the terms used in PoE, but I do know that the devices negotiate about power requirements.
I can see phones being PoE - but not speakers and hifi systems (well, maybe simple control panels).
I understand better what you are looking for, but I still think you are being a little over-complicated. I certainly don't know of any such switches (but then, I know more about office network switches than the sort of thing you are looking for).
All of the switches (with the exception of the 16 port Gb switch mentioned above) will be located in an "equipment closet" -- along with any backup power source (battery). All of the network cabling for these mentioned devices terminates there. Keeps the clutter confined to one place *and* lets me put the backup in a place where all the (PoE) loads can benefit from it.
Yes. I've only listed the PoE devices, here, as the non-PoE devices (servers, PC's, other network fabric, etc.) aren't affected by this.
Consider:
- all of these loads are small -- well within PoE capability.
- control/display panels are small LCD touch panels located "where convenient" in the various rooms. The 21st century equivalent of "light switches". E.g., in addition to rooms, there's one inside each doorway (lets you view video of who is on the other side before opening the door; also lets you arm/disarm security system, tell the house you are departing or arriving so it adjusts HVAC, lighting, etc.). There's one in the "bedroom hallway" where you would typically find a HVAC thermostat (used to tell the house you are retiring for the night or waking in the morning, etc.). These aren't locations where you would want to have to have a power outlet nearby *and* a cord from said outlet up to the display panel (ugly).
- pan/tilt cameras are mounted high on the outside of the house. Power isn't usually available n those places. If it was, it would have to be GFCI protected.
- VoIP phones *could* be accompanied by wall warts -- but that means you have to locate the phone near an electric outlet and now have a second cable running from the phone to the wall. It also means the phone goes dead when power fails (or you have to put UPS's near key phones)
- network speakers are located in the ceiling or in single gang "junction boxes" in the walls (and a "speaker wire" connects the electronics to a "HiFi speaker" located nearby,
*outside* the wall). By putting the (small) amplifier in the "network speaker", you don't need to *add* amplification (and teh AC power supply it would require) for modest sound levels (I'm no longer a teenager... don't need wall-shaking sound anymore! :> ). If you *want* additional amplification, run the outputs through a pad and feed a traditional "HiFi preamp/amp".
- network video mimics the speakers. While a "pure" video device (e.g., STB) could be colocated with AC power, note that I also use the control/display panels with this capability. E.g., I can route security camera video to the display panel by the front door so I can see who's outside before answering. Why create two types of video to address this need alongside the "television" need (i.e., you would also like to be able to see who is at the door while watching TV...)
[There are a few singleton PoE devices that I have mentioned as well. But, all share the fact that you *need* to have a communication link to them so why *also* have the requirement for a separate power cable/supply?]
In the home environment, you don't necessarily *want* to backup all these devices especially if that shortens the backup time available (for a given size/cost UPS, etc.). E.g., as long as *one* phone works, why bother backiing up *all* of them? Furthermore, if the phone and switch/PSE have green capabilities, picking up *any* phone could tell the switch "provide this phone with *full* power as the user wants to use *it*, now!" while keeping the other phones quiescent.
We're switching to VoIP phone service so that equipment -- plus our own phones -- need to be usable in the event of an outage (rare, here, but that doesn't mean we want to be without phone in that situation).
You can't see what the cameras are viewing (on a display) if you can't power that display nor "hear" what is being said if you can't power some speaker(s).
I imagine that as the sort of automation I am describing becomes more common, that will change. People will want/need portions of that automation to remain available during an outage. Here, it is not uncommon for people to have diesel generators and/or photovoltaics to have continued access to power without the Utility -- though when operating like that, you want to be able to effectively manage your power consumption to preserve your capacity.
E.g., we would opt to keep the pumps running for the water harvesting system during an outage in Monsoon season -- since power failures are more common during storms *and* we would still want to be able to harvest the water that only comes during those storms!
There is one level of negotiation that happens "in hardware" when the PoE device ("PD" -- Powered Device) connects to the PoE network. This allows the PD to tell the PSE (Power Sourcing Equipment -- in this case, the switch as an "Endpoint" instead of "Midspan" injector) "Hi, I am connected. I am not a short circuit. I am *probably* not a *telephone* that someone has mistakenly plugged into this network connector. I typically consume about 13W of power. I would like it, *now*..."
Once the PSE recognizes the "load" (PD), it provides the requested power. I.e., it has to subtract that "load" from its available reserves/capacity -- even if the device doesn't really *need* that power right now. (the PD must consume a certain minimum "holding current" lest the PSE consider it "unplugged" and *remove* power from that network connection).
LLDP-MED is a first pass at trying to make this negotiation a more dynamic exchange in recognition of the fact that power requirements are not static. E.g., a VoIP phone may need very little power to "monitor its hookswitch" but, once taken off-hook, might require considerably more power to "power up the phone", turn on the backlight, etc.) So, the PSE and PD's must communicate (through a third party?) to manage those loads and the power available for them.
In the future, what I am describing will be the norm. You won't have a DVD player sitting under your "TV". Or, built *into* your TV. Instead, it will be an "internet TV" presenting media from an in-home server (or other video sources -- imagine the "baby monitor" being a VoIP camera in The Nursery instead of just an *audio* "walkie-talkie") or The 'Net.
Aside from the power to run the actual (large) display (which could be an LCD monitor, nowadays), you need very little to pull video off the network and convert it to suitable signals to drive a "monitor"/display.
Likewise, if your audio needs are handled elsewhere, you don't need the power for the audio amplification *in* the STB/"internet TV" (and you don't have to try to hide all those "speaker cables" under the rugs, etc.)
I don't think they exist, yet, because the home automation and multimedia market hasn't matured to that point. Anyone even trying to do this would be forced to apply SOHO kit to the problem... a regular switch, a UPS sitting alongside it, a rack full of audio/video kit, etc. The "equipment closet" doesn't *simply* hold a switch + UPS but, rather, all sorts of other crap to make this happen in a "less integrated" manner. I don't want to have to set aside all that space for "household services" -- especially when there is no real need to do so (i.e., get *rid* of all the "kit" -- put it in the walls, ceilings, *small* STB's, etc.)
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