Hands-On Powerline Networking: How Well (Or Not) Are Latest-Generation Devices Working?by Brian Dipert on September 1, 2011 12:41 AM EST
- Posted in
- Powerline Adapters
Call me a Luddite, but I've always found the whole idea of setting up a dedicated wired connection just to get a gadget on the network to be a superfluous hassle. At least with Wi-Fi, as both Brian Klug and Jarred Walton have exemplified in recent days, all that's normally involved is twiddling a few software settings to bring a widget online. The approach is particularly attractive for mobile devices, which by their inherent natures are incompatible with wired tethers. But, as wireless networking veterans already intimately realize, the process is rarely that simple. First off, there's interference to consider; from Bluetooth transmitters, cordless phones, microwave ovens, and neighbors' access points. Don't forget about reflection and attenuation; glass, metal and tile, chicken-wire mesh in walls, and the like. Finally, consider the fundamental physics-induced range limitations, which no amount of antenna array augmentation and DSP signal boosting can ultimately surmount. All other factors being equal, for example, you're not going to be able to successfully bridge as lengthy a span at 5 GHz as you can at 2.4 GHz.
AC-powered devices aren't portable, of course; they're permanently mated to a nearby wall socket. Here's where hooking up a network-dedicated Ethernet, coax, phone line or other connection has always annoyed me. I've already hooked up one (thick) wire, the AC power cord. Why can't I just use it for network packet-shuttling purposes, too? In fact, I can; that's the whole premise of powerline networking, although few devices (save the occasional router) currently integrate power-and-packets within them. Instead, indicative of the still-embryonic state of this particular market, you're forced to externally connect a dedicated Ethernet-to-powerline bridge adapter, which you then connect to a different AC socket.
Conceptually, however, the single-connection vision remains valid. And I've noticed encouraging signs of market maturation in recent months. Now-conventional '200 Mbps' powerline adapters are now advertised on sale for around $50 for a two-pack; that's less than half the price that manufacturers and retail partners were promoting them at not so very long ago. And latest-generation '500 Mbps' adapter two-packs are selling for not much more moola; $75 or so. I've been daily using as well as periodically evaluating various powerline networking technologies since the early portion of the last decade, back in the '14 Mbps' HomePlug 1.0 days (say hi if you ever see me at a show, and I'll show you my scars ;-) ). Given recent trends, I figured it was high time for an evaluation revisit. How well do latest generation adapters fulfill their marketing promises? Is it finally time to dispense with burrowing through dirty, spider- and snake-infested crawlspaces and drilling holes in walls and floors in order to route Cat5e cable around?
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metageek - Thursday, September 1, 2011 - linkSo, what happens if a power surge comes in through the outlet? Do these things include surge suppression, or is that surge going to travel out over the Ethernet cable and fry your computer?
kmmatney - Thursday, September 1, 2011 - linkThey have built-in power surge features. These are mainly used to keep the network signal clean, but they also protect the device.
metageek - Thursday, September 1, 2011 - linkThanks.
ranster - Thursday, September 1, 2011 - linkI've been using Linksys PLE200s in my home for a long time now. I got the first pair (sold as a PLK200) for like $140, then later Sears had a sale online for $90, a good deal at the time, so I got another pair. I picked up a third pair off ebay for $14 since only one worked, but not an issue to add on just one. Lastly, I got a new PLK when Circuit City was going out of business, for a mighty good price. I have five of the seven in use, and the Linksys utility shows throughput from ~60Mbit to ~130 Mbit, depending on which PLE and its location in the house.
I might check into the newest standard since they are said to interoperate with the HomePlug AV standard that PLE200s use.
durinbug - Thursday, September 1, 2011 - linkI've been interested in powerline networking for the last couple of years, and I appreciate the attempt to do a thorough investigation of the technology, but the results just don't turn out to be useful.
I've been considering connecting my PS3 in the living room with the router (and desktop) in my office. Right now I use 802.11g (since the PS3 doesn't support n), which nets me a connection speed that ranges from ~10-15 mbps (a laptop also on G in the same location gets 30-40 mbps - the PS3 wireless adapter really seems to be craptastic). This is sufficient for playing games, but can be a major headache for streaming video.
While the throughput data you present here suggests that powerline networking might be an improvement, it doesn't really help make that decision. At an apparent average of about 30-40 mbps that you got, it wouldn't take a whole lot of interference to bring it down to the speeds I'm seeing already.
That said, I understand why you wanted to show the "best case" - I just wish you had also shown the "normal use" case so we might have some idea of the potential speed reduction we might see. I have numerous compact fluorescent lights, refrigerator, etc. (plus living room and office are on separate breakers, don't know about phases) - so even after reading your article I am no closer to knowing whether powerline networking will work for me. So after all the work of writing the article, the take-away seems to be "this is what I got; I have no idea what performance you will see."
bdipert - Thursday, September 1, 2011 - linkDear durinbug, I appreciate the feedback. The fundamental issue that a reviewer such as myself always struggles with in a situation iike this (or Wi-Fi or phoneline or coax, for that matter...any non-networking-optimized interconnect media) is what is 'normal'. Note that my testing (for unfortunate reasons that I discuss in the article) was TCP-only, whereas your streaming situation would likely use UDP instead. From my past experience with powerline products, you would likely experience a 50%-to-100% performance improvement in average UDP transfer rate versus the TCP numbers that I published. Every technology subsequent to first-generation HomePlug 1.0 has focused the bulk of its development and implementation attention on UDP (for likely obvious reasons)
demonbug - Thursday, September 1, 2011 - linkI appreciate the response, and wanted to reiterate that I really do appreciate the in-depth information and test results you provided. It would just be nice to get some sense of the impact on performance things like running the refrigerator or CFLs might have, even if your case doesn't represent the "normal". There is enough variability in throughput as it is, even with the semi-idealized setup (lights off, etc), that I'm a little concerned about maintaining throughput with such sources of interference present.
Your mentioning that you generally see 50%-100% faster UDP transfer rates makes me hopeful that it actually would be a significant improvement over what I have now (and save me from trying to run cat5 through an exterior wall, which looks to be no fun at all), so I just might have to go and pick a couple up.
dennishodge - Thursday, September 1, 2011 - linkNow that the Sonos Bridge is only $50, went Sonos and bought an extra Bridge just to plug my laser printer into. I used to have powerline ethernet but the devices were flaky and eventually the last pair died. Each Sonos component has 1-2 10/100 switches. I haven't done a speed test, but the latency is superb. I even have an old wifi router plugged into a Sonos amp in one end of the house to extend my wifi coverage for weak devices like cell phones.
It would be cool to trial two $50 bridges vs. powerline ethernet :-)
EarthwormJim - Thursday, September 1, 2011 - linkIt seems to me for about the same cost as some of these high speed powerline networking setups, you could just hire an electrician to wire some ethernet jacks throughout your house.
bdipert - Thursday, September 1, 2011 - linkDear EarthwormJim, the hourly labor rate for electricians must be much lower where you live than where I do ;-) Your comment also prompts me to make a related point...retrofitting an existing structure for Cat5e by "burrowing through dirty, spider- and snake-infested crawlspaces" underneath floors (of which I have repeated past personal experience, back where I used to live in Sacramento CA) isn't even an option for a basement- and crawlspace-less residence built directly on a concrete slab...