Original URL: http://www.reghardware.com/2007/01/22/review_netgear_hdx101/
Netgear HDX101 200Mbps powerline Ethernet adaptor
HD-ready wired networking via your home's power ports
Review It's a neat trick being able to transmit data around your home or office via the mains power wiring. You get a more stable, less interference-prone connection than Wi-Fi and a potentially faster link too. The downside is that there's no roaming, at least not beyond the reach of an RJ-45 cable and however many powerline adaptors you've got dotted around your house.
Just as Wi-Fi is due to get a major speed bump, with 802.11n, so too is powerline Ethernet. The difference: the 200Mbps powerline is here now, while the 380Mbps 802.11n isn't going to be ratified until later this year, though we're likely to start seeing a raft of standard... almost products come in the next few months.
Scenting an opportunity, makers of powerline network products are beginning to push the faster technology, particularly now that consumers are starting to ponder streaming HD video around their homes. With that in mind, Netgear last year began packaging its already-available HDX101 200Mbps adaptor as a pair of units in a 'starter kit'.
Netgear was able to get to market well ahead of its rivals by adopting a different technology. The best known powerline system, the de facto standard, is HomePlug, touted by the HomePlug Alliance [1]. Almost everyone supports HomePlug's 14Mbps and 85Mbps standards. Unfortunately, delays to the ratification process meant the 200Mbps HomePlug AV specification wasn't approved until the summer of 2006.
In the meantime, chip maker DS2 [2] had already started offering 200Mbps powerline chipsets by adapting an existing European standard called Opera, developed for broadband connections between homes and electricity sub-stations. Alone among powerline Ethernet adaptor vendors, Netgear chose to use the DS2 system rather than wait for HomePlug AV to be finished.
If you already have 14Mbps or 85Mbps HomePlug-based powerline adaptors in place, any HDX101s you add will happily co-exist with them, Netgear claims. But don't expect them to communicate with each other. Opera is incompatible with HomePlug 1.0 (14Mbps) and HomePlug 1.0 Turbo Mode (85Mbps). Nor is it compatible with HomePlug AV. Which, in case you were wondering, isn't compatible with the slower HomePlug specifications either but, again, will co-exist with them.
So don't expect a Netgear HDX101 to talk to a Devolo DLAN 200 AVdesk like the one I reviewed last week [3] or the Solwise HomePlug AV 200Mbps I'll be looking at in due course.
The HDX101 is a little larger than other powerline network adaptors I've seen. As usual, the plug pins are on the back, along with a small sticker detailing the device's serial number and, more importantly, the MAC address. Why can't anyone print these somewhere else so you can read them when the device is plugged in? Netgear's missed a trick here.
Other adaptors place the Ethernet port on the bottom of the device, but Netgear opted to situate it on the left side. This may necessitate some plug juggling to prevent adjacent plugs stopping you from getting the network cable into the adaptor. I doubt it, though, because such is the size of the HDX101 you're probably not going to able to plug anything in next to it, certainly little that's larger than a standard plug.
The device's size arises primarily from the integrated transformer. And in case you're wondering why no powerline adaptor maker includes a pass-through power port, that's one reason. Adding the socket would mean the transformer would have to go elsewhere in the casing, increasing the adaptor's overall size. More to the point, perhaps, every vendor would have to gain further degrees of electrical standards compliance certification, upping the product's cost as well as the size.
The price would also increase if Netgear had opted to fit the HDX101 with a Gigabit Ethernet controller and port. As it stands, the adaptor is equipped with a 10/100Mbps port - fine for a 14Mbps or 85Mbps device like past powerline adaptors, but not, surely, for 200Mbps ones?
Well, yes, because the HDX101 doesn't actually operate at 200Mbps. That's the theoretical maximum speed the technology is capable of. In the real world, once you've suffered signal attenuation on the cabling and wiring, and you've allowed for Ethernet protocol and error-correction codes, the data transfer speed is within the limits of the 100Mbps Ethernet controller. Well, so say makers of powerline Ethernet products. I'm not entirely convinced, but they all ship their 200Mbps products with 100Mbps Ethernet controllers.
In the HDX101s' favour, they're a doddle to connect and get running - they really are plug and play. Netgear helpfully bundles two 1.8m RJ-45 cables, one for each of the devices you'll connect to the two HDX101s. Plug the two devices in and they soon detect each others' presence and begin communicating. Establishing a connection doesn't take place anywhere near as quickly as it does with the Devolo units, I found. Two AVdesks connected in a few seconds; the HDX101s established a link in just under 30 seconds.
You can argue that that doesn't matter if they adaptors are kept continually powered up, but if there's a sudden loss of connectivity because a unit is inadvertently unplugged, or you're of a mind to turn the adaptors off overnight, reconnection speed can be an issue.
I used two HDX101 units to connect a MacBook Pro and a Sony Vaio notebook between upstairs and downstairs rooms in my apartment. Powerline Ethernet adaptor suppliers warn against using multi-socket boards, but I had to and so, I suspect, will many other users. Avoid boards with surge-protection circuitry - that's the killer, I'm told. For testing, I used a simple two-socket extension cable with nothing plugged into the second socket.
I first used the open source network testing tool iperf [4] to measure the link's TCP and UDP available bandwidths and got 56Mbps and 59.4Mbps, respectively. That compares to the 50.6Mbps and 59.4Mbps I recorded for the Devolo units over the same stretch of mains cabling. It's worth noting, perhaps, that when monitoring network usage with Windows Task Manager, the Devolo box produced a smoother chart than the Netgear.
Using the open source media playback and streaming application VLC [5], I was able to stream a 1080i HD video in MPEG 2 from the PC to the Mac with no trouble at all. There was clearly sufficient bandwidth to send the same video simultaneously from the Mac to the PC, although playback on the PC was very juddery because its GPU and CPU lack the power to decode the image data smoothly, not for bandwidth limitations.
While streaming the video to the Mac, I also measured the remaining available TCP bandwidth using iperf. So while Devolo's old 85Mbps adaptors, which I reviewed early last year, can smoothly transmit the HD stream, running iperf alongside it caused some picture break-up and yielded an available bandwidth figure of just 3.7Mbps.
The HDX101 pair continued to stream the HD content smoothly while iperf was running, with the measurement tool reporting there was 37.9Mbps of 'spare' bandwidth - enough for a second HD stream, and you might even get a third going if your own link's particularly good.
Netgear bundles the HDX101s with a configuration utility that allows you to adjust the adaptors' quality-of-service (QoS) settings. I got the above results with UDP traffic - the protocol most commonly used for streaming video data - prioritised. Setting the adaptors to prioritise TCP traffic - internet data essentially - the available TCP bandwidth went up to 54.7Mbps, but the HD playback began to get jerky. Turning off QoS, did not affect video playback and yielded a TCP bandwidth of 47.3Mbps.
Measuring powerline Ethernet bandwidth is a tricky business, of course. The capacity you get can vary according to which power socket you use, what else is connected and the overall quality of your wiring. But my tests suggest HDX101s will support multiple HD streams and provide enough bandwidth to share an internet connection and for multi-player gaming.
Verdict
Netgear's HDX101 is a solid powerline adaptor, but there are a couple of points to consider before buying one. I wouldn't hesitate to recommend it for performance, but there's the little matter of its incompatibility with other so-called 200Mbps products - if you want more units, you'll have to buy HDX101s if you want them to talk to each other. It's also quite a chunky unit, and it does suffer from a much slower connection initiation speed than its rivals. On the plus side they're about £20 cheaper than, say, Devolo's equivalent units. ®
Hard Facts
Netgear HDX101 200Mbps powerline Ethernet adaptor
HD-ready wired networking via your home's power ports
High-speed home networking through power sockets...
Suggested Price: £65 per unit; £128 for a two-adaptor pack
More Info: Netgear's HDX101 page [6]
