High-speed powerline networking

High-speed powerline networking

Summary: Powerline networking has had a troubled history, not least of which is the ongoing rivalry between the Homeplug Powerline Alliance (HPA) and DS2's Universal Powerline Association (UPA). The fastest HPA standard is currently Homeplug AV, which offers 200Mbps speeds, although a 1Gbps Homeplug AV2 standard is in the pipeline and may appear in 2011.

TOPICS: Reviews

Powerline networking has had a troubled history, not least of which is the ongoing rivalry between the Homeplug Powerline Alliance (HPA) and DS2's Universal Powerline Association (UPA). The fastest HPA standard is currently Homeplug AV, which offers 200Mbps speeds, although a 1Gbps Homeplug AV2 standard is in the pipeline and may appear in 2011.

These two new high-speed products from Solwise and Netgear are Homeplug-certified, maintaining full compatibility with existing Homeplug AV equipment, but use two different methods to offer 1Gbps (Solwise) or 500Mbps (Netgear) speeds. Neither is compatible with UPA-certified products.

Solwise 1Gbps Mediaxtream Homeplug AV

The Solwise adapters are based on a novel chip from Gigle Networks, the GGL541 (also used by Belkin in its Powerline HD adapters), which uses a proprietary technology called Mediaxtream to achieve 1Gbps PHY rates. It does this by signalling using a 50-300MHz frequency band instead of Homeplug AV’s 2-28MHz band. The chip also incorporates a meshing technology called Xtendnet that's designed to improve performance in noisy conditions. The adapters can connect to Homeplug AV devices at full 200Mbps speed, with connection speeds indicated by coloured LEDs — blue for Mediaxtream and green for Homeplug AV. They will co-exist with Homeplug 1.0 devices, but are not interoperable.

There’s a Gigabit Ethernet port, a connection button and a reset switch on each adapter. The cost is £44.66 each (inc. VAT). We tried out a pair of these adapters and saw real throughputs (using Passmark's Network Test) in a normal domestic environment of around 90-95Mbps, which compares favourably to the 35-40Mbps we achieved with Homeplug AV adapters.

Netgear Powerline AV 500

Netgear's new range is rather more comprehensive, with both basic and 'piggyback' (with a passthrough mains socket) models available. Although Netgear doesn’t indicate the silicon used, it seems likely that these could be using the Atheros AR7400 chip, launched at the beginning of 2010. This extends the Homeplug AV frequencies up to 68MHz in order to achieve the increased speeds, and again is fully compatible with Homeplug AV. A Gigabit Ethernet port is provided, and the AV+ models include the filtered passthrough mains outlet.

Both AV 500 and AV+ 500 models are available individually or in paired kits. US pricing is $159 for the AV twin-pack and $179 for the AV+ 500 twin-pack; UK pricing and availability has not yet been announced.

Netgear has also announced a new Homeplug AV device, the Powerline AV 200 Wireless-N Extender Kit. This features a 100Mbps Ethernet port plus a 2.4GHz 802.11n Wi-Fi radio. A kit consisting of one Wireless-N adapter plus a wired AV 200 adapter costs $169.99.

Powerline networking is an incredibly convenient way of creating or extending a network in places where network cables or Wi-Fi are impractical. With speeds edging higher and prices reducing, it's certainly not the slow and expensive option it once was. Although they're unlikely to deliver anywhere near the headline speeds in the real world, it looks as though these new models should deliver noticeable performance improvements.

Kelvyn Taylor

Topic: Reviews

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  • I can't help feeling nervous about Powerline. Not so much the idea of connecting my network to the mains, as I'd have to assume that there's more than one fail-safe mechanism inside one of those boxes. It's more the fact that, as more people use them, the more likely it is that my packets will be sitting on the same physical network as my next door neighbour's.

    You might argue that this is effectively true when using Wi-Fi, but at least I have some measure of control there, and a good deal of thought has (at last) gone into securing wireless networks. Is this true of Powerline?
    Manek Dubash
  • The whole idea is a train wreck waiting to happen. These things dump crap over huge swathes of the radio spectrum, and are already causing problems for legitimate radio users, including police, aircraft & emergency services.

    They rely on a loophole in the law by claiming not to be radio transmissions - ignoring the fact that any unshielded wire is a de-facto aerial. OffCom, have stuck their fingers in their ears and gone 'La-La-La. Not our remit' in spite of formal complaints from the above organisations, as well as from radio amateurs (who incidentally accurately predicted both the effects, and OffCom's response).

    This only works if just a few people use it, otherwise the units not only wipe out everything else, but also each other. The BT units are particularly offensive. Here is a telecom company dishing out units that actually interfere with ADSL!!! Mind you, BT is a company that works on the basis of absolutely maximum profits, no matter the damage to even their own customers.
  • @ Manek: Good point, although you do need physical access to an existing adapter in order to add a new adapter to the network. The network SSID (yes, it's effectively a form of Wi-fi) can easily be changed to a new random value at any time, as long as you have access to all the adapters. Data is secured using 128-bit AES encryption. Only twin-packs are pre-paired, so singles have to be joined to an existing network manually.
    Unfortunately there's no monitoring utility shipped with the Solwise units, as there is with most other Homeplug units I've seen, so you can't keep an eye on what's been plugged in. Don't know whether the Netgear models have such a tool - will let you know when I get hold of one.

  • Thanks Kelvyn - it's interesting that vendors have chosen to use Wi-Fi security techniques. It speaks highly to the point that Tezzer makes about the RF interference, which I have heard mentioned on more than one occasion.

    It's a bit like the Chunnel: it was great when few people were using it but now it's mass market, it's only marginally faster than other methods of getting there.
    Manek Dubash
  • I've just heard from Solwise that a problem has been discovered with the first batch of Gigabit adapters they sold - a faulty power supply causes them to reboot on noisy cabling. I noticed this when testing one unit and reported it to them. The problem has been fixed, and Solwise has already sent out free replacement units to all those who had purchased them.