Guide to your home's hidden network 

You have ultrafast broadband access to your home or small office, but only one of your computers can access it. You have a fabulous new printer, but only one of your computers is wired to use it. It sounds like the one thing you don't have is a home network. 

Most homes and many older offices aren't wired for Ethernet. Heck, they're not even set up for phones in every room, and the idea of installing broadband wiring by yourself is as scary as the thought of doing your own orthodontia. The most common solution is a wireless network using either 802.11b (Wi-Fi) or the faster 802.11a, but these networks have limited range, and throughput decreases the farther away you get. So unless you're ready to hire an electrician to drag cable through your wall cavities, you have only one other set of cords to use: the ones from which you get your electricity. 

Sure enough, there is a technology standard for computer networking through 110V power lines--just by plugging an adapter into a two- or three-pronged power outlet. It's called the HomePlug 1.0 standard, and products that meet it can connect PCs, Macs, routers, and Ethernet-based Internet devices such as radios and game consoles.

So your home's already wired for a so-called power-line network. What else is there to know? Read on for instructions, advice, and reviews of four top power-line products. 

Introduction to Powerline Home Networking and HomePlug

Most home computer networks are built to support a mix of devices communicating over Wi-Fiwireless and/or wired Ethernet. Powerline home network technology represents an alternative way to connect these devices that offers some unique advantages.

HomePlug and Powerline Networking

In 2000, a group of networking and electronic firms created the HomePlug Powerline Alliance with a goal to standardize powerline technologies for home networks. This group has produced a series of technical standards named as versions of "HomePlug." The first generation, HomePlug 1.0, was completed in 2001 and later superceded with HomePlug AV second-generation standards introduced in 2005. The Alliance created an improved HomePlug AV2 version in 2012.

How Fast is Powerline Networking?

The original forms of HomePlug supported maximum data transfer rates of 14 Mbps up to 85 Mbps. As with Wi-Fi or Ethernet equipment, real-world connection speeds do not approach these theoretical maximums.

Modern versions of HomePlug support speeds similar to those of Wi-Fi home networks. HomePlug AV claims a standard data rate of 200 Mbps. Some vendors have added proprietary extensions to their HomePlug AV hardware that boost its maximum data rate to 500 Mbps. HomePlug AV2 supports rates of 500 Mbps and higher. When AV2 was first introduced, vendors produced only the 500 Mbps capable gear, but newer AV2 products are rated for 1 Gbps.

Installing and Using Powerline Network Equipment

A standard HomePlug network setup consists of a set of two or more powerline adapters. Adapters can be purchased individually from any of multiple vendors or as part of starter kits that contain two adapters, Ethernet cables and (sometimes) optional software.

Each adapter plugs into a power outlet which in turn connects to other network devices via Ethernet cables. If the home already uses a network router, one HomePlug adapter can be joined to the router to extend the existing network with powerline-connected devices. (Note some newer routers and wireless access points may have HomePlug communication hardware built in and not require an adapter.)

A few HomePlug adapters feature multiple Ethernet ports allowing multiple devices to share the same unit, but most adapters support only one wired device each. To better support mobile devices like smartphones and tablets that do not have Ethernet ports, higher-end HomePlug adapters that integrate built-in Wi-Fi support can be installed, allowing mobile clients to connect direct via wireless. Adapters typically incorporate LED lights that indicate whether the unit is operating properly when plugged in.Powerline adapters do not require software setup. For example, they do not possess their own IP addresses. However, to enable the optional dataencryption feature of HomePlug for additional network security, a network installer must run appropriate utility software and set a security password for each connecting device. (Consult the powerline adapter vendor documentation for details.)Follow these network installation tips for best results:

plug powerline adapters directly into wall sockets whenever possible – avoid UPS devices, power strips, multi-way extensions or extension cords as these may generate electrical interference that disrupts the network. Surge protectors in particular interfere with the operation of powerline adapters.

avoid using HomePlug 1.0 adapters – 1.0 connections are relatively slow and not compatible with newer HomePlug standards

enable encryption when using HomePlug in multi-residence buildings. While powerline encryption is not needed in single-family dwellings because the home wiring cannot be remotely accessed, other HomePlug users attached to a building's shared power grid can easily snoop each other's network traffic unless it is encrypted.

What is power-line networking?

Home power lines have been used to network devices for more than a decade now. Companies including x10 and IBM have designed entire home automation systems--for remote control of lights and appliances--around standard electrical wiring. And adapters from companies such as Phonex use power lines to carry phone signals to rooms without phone jacks. But until this year, the computing industry has been without a standard that enables regular computer and Internet devices to use 110V wiring for sharing data and resources. The HomePlug Powerline Alliance has now filled that gap with its HomePlug Alliance 14Mbps-certified program. 

What's the setup?Power-line adapters come in two basic flavors: those with USB interfaces, and those that

plug into Ethernet ports. Want to share a printer between computers in two rooms? Plug a power-line adapter into each computer. Want to share broadband Internet access? The simplest way is with an Ethernet broadband router. With the router sitting between your cable or DSL modem and your hard-wired online computer, you're free to expand your broadband access to other computers. Simply attach a HomePlug power-line adapter to the router and plug it into the wall power socket. Then attach an Ethernet or USB power-line adapter to any PC, Mac, or Internet radio you want to access. You may need to install a driver onto your PC and maybe run your computer's Internet configuration software, but otherwise, it's a fairly easy operation. 

 Typical Powerline network setup

HomePlug Certification Mark

How does it compare with other networking standards?

HomePlug's standard has physical advantages over its competition, too. It doesn't require special wiring like Ethernet networks do, and it can do something that wireless networks can't: communicate between the attic and the basement of a four-story house. Wireless networks have a working range of about 150 feet, and the connections get slower the farther the wireless receiver is from its base station. HomePlug networks, on the other hand, have a range of about 1,000 feet of power cable. 

Power line's theoretical data transfer limit is 14 megabits per second (Mbps), but in practice, it exchanges data at less than half that rate. That's still faster than the more affordable of the two Wi-Fi specs, 802.11b, which has a practical throughput of 4Mbps to 5Mbps. But of course, it's slower than 802.11a's practical 22Mbps and fast Ethernet's 100Mbps. In other words, power-line networks are plenty fast enough for sharing files, Internet access, and peripherals such as printers, though maybe not great for a streaming videoconference or multiplayer gaming. 

  Pros Cons Approximate range

Claimed/typical data speeds

Ethernet Cheap ($10 for adapter)Included on most new PCsHundreds of hardware makers

Requires cablingLarger networks need distribution hubs and switches

300 feet per segment

100/1000Mbps*

Power line

Uses existing home wiringGovernment-strength 56-bit DES encryption

Relatively expensiveVulnerable to spikes (sudden rises in energy), surges (prolonged overvoltages), and brownouts

1,000 feet 500/1000Mbps*

Wi-Fi5 (802.11ac)

High bandwidth fro multiple users or multimedia distributionEight channels

Expensive ($150 for PC Card adapter)Small number of manufacturersNot integrated on notebooksNo certification

50 feet 450/1750Mbps*

Bluetooth Very cheap ($5 to $7.50) for integrated radio on PDA or phoneWidespread installationLow power use

Low throughputShort rangeLack of compatibility

20 to 50 feet 1/24Mbps

*For Gigabit network 

The cost of power-line networking

To install an Intelogis PassPort power-line network, you plug a wall device like this into an outlet.

HomePlug power-line networking is often accused of being expensive, but it's not necessarily any pricier than the alternatives. You can pick up HomePlug adapters from GigaFast and NetGear, for example, for between $80 and $100 apiece--in about the same range as Wi-Fi adapters (which retail for about $60 to $100). With these adapters, a three-computer power-line network would cost around $300. A Wi-Fi network will cost roughly the same when you factor in $150 for the base station. And the Wi-Fi gear tops out at 500Mbps. At longer range, it's even slower; in fact, you may need to pay an extra $60 or so for a range extender to get comparable data rates. 

But in general, HomePlug isn't the cheapest way to network a house or office. Home Phoneline (HPNA 2.0) USB adapters cost around $30 (or $100 for HPNA Ethernet bridges), which can work out cheaper, if you have phone lines in every room you want to network. And to enable Internet sharing over HomePlug networks, you need to spring for a broadband router, which will put you $60 or so above a wireless network budget. But that's small beans when you factor in the system's setup simplicity. 

Intelogis provides a kit that connects two computers and one printer for $59. Additional adapters cost about $40. There are specific versions for computers or printers, so make sure you get the correct one. Since the network does not affect power usage or consumption, no additional monthly costs are incurred.

The cost of PowerPacket technology is expected to be comparable to HomePNA solutions and significantly less than 802.11 wireless solutions.The physical connection between each computer and the Intelogis power-line network uses the computer's parallel port. A wall device is plugged directly into the electrical outlet (it will not operate properly if plugged into a surge protector).

A parallel cable is plugged into the wall device and into the parallel port of the computer. The power-line network must be the last item connected to the parallel port. For this reason, if you have anything else connected to the parallel port, such as a scanner or Zip drive, it must have a pass-through for the parallel port. Unless you have a second parallel port on your computer, your printer must be connected to the network through a wall device of its own. Something to keep in mind is that current power-line networks do not support bidirectional printing. "Bidirectional" means that data is sent in both directions, allowing your printer to send information back to your

computer, such as how much ink is left and if there is a paper jam. This will not keep your printer from working, but it is worth noting that you will lose the use of such features.

Initial PowerPacket devices connect via a USB or Ethernet cord from the computer to a small wall adapter. Subsequent devices will have the circuitry built in, meaning the only connection needed would be the power cord.Once the physical connections are made, installation of the software is a snap. The software automatically detects all nodes (computers and printers) on the network. Whether your Internet connection is by cable modem, DSL or normal modem, the included proxy server software allows you to share the Internet with your other computers. You can easily add computers by simply plugging a new adapter in and installing the software. Additional printers can be added using the printer plug-in adapter. File and printer sharing is done through Windows.

There are two common types of home networks: peer-to-peer and client/server. Client/server networks have a centralized administrative system that provides information to all of the other devices. Peer-to-peermeans that each device can talk directly to each other device on the network without consulting a central system first. Intelogis Passport technology uses a client/server network. The first computer that you install the software on becomes the Application Server. In essence, it is the director of the network, controlling the flow of data and telling each device on the network where to find the other devices. Intellon's PowerPacket technology uses a peer-to-peer network.

Home networking - Power line connections explained

Power line networking basically turns a building's existing electrical wiring -- the wires that carry electricity to different outlets in the house -- into network cables, meaning they also carry data signals for a computer network. And this means virtually all households, in the U.S at least, are "wired for" power line networking. It doesn't replace a regular network, so you'll still need a router, but it's a good way to extend your existing network into new places.

Home power line networking is far less popular than Wi-Fi, or even running network cables, however, mostly because consumers are not aware of its existence and benefits. I'm going to change that.

How Power-line Networking WorksThe HomePlug Powerline Alliance hammered out the HomePlug 1.0 specification last

year, with broad industry support from chipset makers Intellon and Cogency and networking manufacturers NetGear, Linksys, Phonex, and GigaFast. HomePlug 1.0-certified products already appear in volume on shelves and can facilitate network communications among PCs, Macs, routers, and Internet devices such as Net radios, all through 110V power lines. 

Power-line adapters do what all analog communication devices do: translate data into a carrier-signal format so that it can be transmitted to another device. The big difference is that 110V power is a tough carrier signal; it's not a perfectly regular sine wave. The signal gets jagged with line noise, spikes, surges, and brownouts (periods of low voltage), all of which makes it a rough medium for communications. But thanks to some smart programming, HomePlug adapters can weather most of these problems and keep your connection live. 

Power-line networking is one of several ways to connect the computers in your home. It uses the electrical wiring in your house to create a network.

Like HomePNA, power-line networking is based on the concept of "no new wires." The convenience is even more obvious in this case because while not every room has a phone jack, you will always have an electrical outlet near a computer. In power-line networking, you connect your computers to one another through the same outlet. 

Because it requires no new wiring, and the network adds no cost to your electric bill, power-line networking is the cheapest method of connecting computers in different rooms. 

Pros and Cons of Power-line Networking

New power-line networking products are based on Intellon's PowerPacket technology.

Because residences often have power outlets installed in every room, cabling a computer to the powerline network can normally be done quickly anywhere in the home. Although whole-house Ethernet wiring is an option for some residences, the additional effort or cost can be high. Especially in larger residences, powerline connections can also reach areas where Wi-Fi wireless signals cannot.

Powerline networks avoid the wireless radio interference from consumer gadgets that can disrupt home Wi-Fi networks (although power lines can suffer from their own electrical noise and interference issues.) When working as designed, powerline connections support lower and more consistent network latency than Wi-Fi, a significant benefit for online gaming and other real-time applications.

Finally, people uncomfortable with the concept of wireless network security may prefer to keep their data and connections protected inside powerline cables rather than transmitting over the open air like with Wi-Fi.

There are two competing power-line technologies. The original technology is called Passport, by a company named Intelogis. A new technology called PowerPacket, developed by Intellon, has been chosen by the HomePlug Alliance as the standard for power-line networking.

The biggest advantage of power line networking is convenience, especially when compared with a regular wired network. Instead of having to run network cables, you just plug the adapters into the wall sockets. You can build a home power line network off your original network in a matter of minutes.

When compared with a Wi-Fi signal, the second advantage of a power line connection is you can extend a network to the far end of a house or a basement easily, which a Wi-Fi signal might have a hard time reaching, especially in homes with thick walls. On top of that, a power line connection is very similar to a regular wired connection in terms of latency, meaning you can access the Internet with almost no lag at all.

Thirdly, compared with Wi-Fi extenders, a power line connection is so much better since you can easily add another Wi-Fi network in the far end of a house independently from the existing Wi-Fi network. In fact, using a power line Wi-Fi extender such as the ZyXel PLA4231 is the best way to extend a home network for both wired and wireless clients.

And, finally, power line technology is now quite affordable, with adapters costing just around $50 for a kit of two. This costs much less than the parts you need to run cable properly.

Summarizing the advantages of a power-line network:

It's inexpensive. (approx. $50.)

It uses existing electrical wiring.

Every room of a typical house has several electrical outlets.

It's easy to install.

A printer, or any other device that doesn't need to be directly connected to a computer, doesn't have to be physically near any of the computers in the network.

It doesn't require that a card be installed in the computer (although there are companies working on PCI-based systems).

The new PowerPacket technology provides a couple of other advantages as well. It is fast, rated at 500 megabits per second (Mbps). This speed allows for new applications, such as audio and video streaming, to be available throughout the house.

ConsPower line networking has a few drawbacks.

First, power line adapter devices need to be plugged directly into a wall socket; they don't work well, or at all, if plugged in a surge protector or power strip. This plus the fact that they are generally large and don't come with a power pass-though socket (though a few do) means they can be a hassle to use at the place where there is just one wall outlet, or outlets that are close to one another.

Second, power line adapters require standard 110v electrical outlets and the data signal between them depends on the quality of the electrical wiring itself. On top of that, improper wiring and circuit breakers can also negatively affect the performance.

Third, power line adapters' performance can be degraded by the noise that certain home appliances generate in the power grid. Examples of these appliances include motorized devices (fans, vacuum cleaners, washer and dryers), switch power supplies (AC-to-DC converter used in phone chargers), and fluorescent lamps.

And finally, using power line connections in an apartment building might lead to a security risk. As the wiring is connected, people living in other apartments could tap in to your network by using an adapter of their own. This is similar to using an open Wi-Fi network. However, all power line adapters come with a security feature to prevent this from happening (note that adapters from different vendors generally don't work well together with security turned on, so you'll be better off with adapters from the same vendor).

Despite the advantages promised by powerline technology, relatively few residential home networks use it today, especially in the United States. Why?

cost - with Wi-Fi chips built into most mobile devices, a homeowner needs only to buy one cheap Wi-Fi router to get started with building their network. Although costs have decreased in

recent years, just one pair of HomePlug adapters can cost more than the router, particularly if integrated Wi-Fi support is needed.

history - when first introduced, users of HomePlug 1.0 products complained of low performance and reliability issues. While powerline products have been significantly improved in newer versions, some people still associate HomePlug technology with these legacy issues.

home electrical wiring limitations - powerline networks can run slow or perform unreliably in some residences depending on inherent characteristics of its wiring. Without actually setting up the powerline network, determining the limitations typically requires employing a professional installer.

If you live in a home, you don't have to worry about your next-door neighbor being able to access your network. Power line signals can't cross a transformer, which is generally what separates street-side power connections.

There are some disadvantages to connecting through power-lines when using the older Intelogis technology:

The connection is rather slow -- 50 Kbps to 350 Kbps.

The performance can be impacted by home power usage.

It can limit the features of your printer.

It only works with Windows-based computers.

It uses large wall devices to access an electrical outlet.

It can only use 110-V standard lines.

It requires that all data be encrypted for a secure network.

Older wiring can affect performance.

According to Intellon, PowerPacket technology eliminates many of these concerns, citing the following advantages:

It is very fast, rated at 500 Mbps.

It "avoids" disruptions in the power-line, maintaining the network's connections and speeds.

It does not limit the features of your printer.

It can be compatible with other operating systems (depending on driver availability).

It may have the necessary circuitry embedded within the device, necessitating only a standard power cord to access an outlet.

It works independent of line voltage and frequency of current.

It includes encryption.

In tests, it showed no signal degradation due to older wiring.

Methods

This card plugs into a PCI slot in your computer and into a wall outlet to create a power-line network.

Photo courtesy Intellon

Intellon and Intelogis use different methods to establish power-line networks.

IntellonIntellon's PowerPacket technology, which serves as the basis for the HomePlug Powerline Alliance standard, uses an enhanced form of orthogonal frequency-division multiplexing (OFDM) with forward error-correction, similar to the technology found in DSL modems. OFDM is a variation of thefrequency-division multiplexing(FDM) used in phone-line networking. FDM puts computer data on separate frequencies from the voice signals being carried by the phone line, separating the extra signal space on a typical phone line into distinct data channels by splitting it into uniform chunks of bandwidth.

In the case of OFDM, the available range of frequencies on the electrical subsystem (4.3 MHz to 20.9 MHz) is split into 84 separate carriers. OFDM sends packets of data simultaneously along several of the carrier frequencies, allowing for increased speed and reliability. If noise or a surge in power usage disrupts one of the frequencies, the PowerPacket chip will sense it and switch that data to another carrier. This rate-adaptive design allows PowerPacket to maintain an Ethernet-class connection throughout the power-line network without losing any data.

The latest generation of PowerPacket technology is rated at 14 Mbps, which is faster than existing phone-line and wireless solutions. However, as broadband access and Internet-based content like streaming audio and video and voice-over-IP become more commonplace, speed requirements will continue to increase. Along these lines, Intellon's OFDM approach to power-line networking is highly scalable, eventually allowing the technology to surpass 100 Mbps.

IntelogisThe older power-line technology used by Intelogis relies on frequency-shift

keying (FSK) to send data back and forth over the electrical wires in your home. FSK uses two frequencies, one for 1s and the other for 0s, to send digital information between the computers on

the network. (See How Bits and Bytes Work to learn more about digital data.) The frequencies used are in a narrow band just above the level where most line noise occurs. Although this method works, it is somewhat fragile. Anything that impinges on either frequency can disrupt the data flow, causing the transmitting computer to have to resend the data. This can affect the performance of the network. For example, this author noticed that when he was using more electricity in the house, such as running the washer and dryer, the network slowed down. Intelogis includes line-conditioning power strips with its network kit and encourages you to insert them between the wall outlet and your computer equipment to help reduce the amount of electrical-line noise.

Because the current crop of power-line networks are designed to work on 110-volt electrical systems, the technology is not very useful to countries outside of North America that use different standards.

Common applications

Power line networking is used in many ways, including in large projects such as smart grids and power line broadband service, which uses power line connectivity to provide an Internet signal, just like a DSL service that uses an existing telephone line for the same purpose. However, in this post I'll only talk about home power line networking, where the technology is used to connect either Ethernet-ready (wired) devices, or Wi-Fi (wireless) devices.

Connecting wired devices: This is the most popular use of power line networking and generally is based on power line adapters. Each of these adapters has at least one network port.

You need two adapters to create the first power line connection -- this is why most adapters are available in a kit of two.

The first adapter is connected to a router (or a switch) of an existing wired LAN (local-area network), via its network port. The second adapter is connected to an Ethernet-ready device (such as a computer or a printer). Now just plug both adapters into their wall sockets and you will add the Ethernet-ready device to the network. There's nothing else connecting the two adapters other than the electrical wiring in between the two wall sockets being used.

A typical power line adapter has at least one network port, to work as one end of a power line connection.

(Credit: Dong Ngo/CNET)

After the first connection is created, you need another adapter for each additional network device (usually. Some power line adapters have more than one network port so they can support multiple Ethernet-ready devices at the far end of a power line connection.)

Connecting wireless devices: This is similar to connecting wired devices, but in this case the second adapter has a built-in access point to create a Wi-Fi network of its own. The LAN is extended from the first adapter to the second one, which then broadcasts a Wi-Fi signal so that wireless devices, such as laptops, tablets, and smartphones, can be part of the network.

Some networking devices, such as routers or switches, also have power line connectivity built in. Two examples are the D-Link DHP-1320 Wireless N PowerLine Router and the D-Link DHP-540 PowerLine AV 500 4-Port Gigabit Switch. This type of combo device makes sense because they need to be plugged into the wall to operate anyway.

Some power line adapters, such as this one, have more than one network port and even a built-in Wi-Fi access point to

support multiple clients.

(Credit: Dong Ngo/CNET)

Power line standards

Power line networking is being developed by the HomePlug Powerline Alliance and there are two main standards that you should know: HomePlug 1.0 and HomePlug AV.HomePlug 1.0 was first introduced back in 2001 and has a cap speed of 14Mbps. It's now becoming obsolete.HomePlug AV, introduced in 2005, has an initial cap speed of 200Mbps, which is fast enough to carry multimedia content, hence the AV designation for Audio and Video. This standard also supports 128-bit AES encryption for security. HomePlug AV is backward-compatible with HomePlug 1.0 and is marketed as Powerline AV (or Powerline AV 200).Powerline AV adapters have a real cap of just 100Mbps as they also support the regular 10/100 Ethernet standard. In testing, the actual sustained speed of these adapters is somewhere from 20Mbps to 60Mbps.

Examples of Powerline AV/200 devices are the Netgear Powerline Av 200 Wireless-N Extender Kit, the D-Link DHP-1320 Wireless N PowerLine Router, and the WD Livewire Powerline AV Network Kit.

HomePlug AV got a boost with the ratification of the IEEE 1901 specification in 2010. Whereas previously Powerline was an independent standard, this brought it under the same umbrella as the other networking standards and protocols. This specification guarantees

interoperability between adapters from different vendors, and on top of that the cap speed is now increased to 500Mbps. This much faster HomePlug AV is marketed as Powerline AV 500.Powerline AV 500 offers real-life cap speeds of either 100Mbps or 500Mbps depending on the type of network port the adapter device supports, be it regular 10/100 Ethernet or Gigabit Ethernet. In real-world testing, Powerline AV 500 indeed offers significantly higher sustained speed than Powerline AV, giving speeds ranging from 90Mbps to 200Mbps.

Most power line adapters come in a kit of two.

(Credit: Dong Ngo/CNET)

Examples of Powerline AV 500 devices include the ZyXel PLA4231 500 Mbps Powerline Wireless N Extender, the Trendnet Powerline 500 AV Nano Adapter Kit, and the D-Link DHP-501AV PowerLine AV 500 Adapter Starter Kit.

There's also a new standard called HomePlug AV 2 that promises real Gigabit Ethernet network speed via a power line connection. This new standard is compliant with the IEEE 1901 specification and will be backward-compatible with existing HomePlug AV devices.

How to Secure Your HomePlug Powerline NetworkOnly you have the power to secure your powerline network

Photo: Lauren Burke / Getty

There used to be two basic options for setting up a network in your home. You could either string Ethernet cables all over the place or you could invest in a wireless access point or wireless router and go wireless. Over the last few years a third option has emerged and started to catch on.

Enter: the HomePlug Powerline network. Powerline networks use your home's electrical wiring to carry network traffic at speeds that rival traditional wired network technologies. Powerline networks are super simple to implement thanks to theHomePlug Powerline Alliance who has done their best to make Powerline network products interoperable and easy for consumers to install.

The basic Powerline network consists of at least two Powerline network devices which look like little bricks that plug into your home's power outlets. Each Powerline network adapter has an Ethernet port to connect network devices to.

Say you have a computer in your basement and your Internet router is on the third floor of your house. Instead of running a network cable up to the third floor, all you would need to do is take a Powerline network adapter, plug it in near your computer in the basement, connect the cord to your computer and to the powerline adapter, and follow the same process with another Powerline adapter, plugging it into your router and a power outlet near you router. Boom. You're done!

If you want to add more devices in other rooms to the network, you just need to buy more Powerline network adapters. Some versions of the homeplug standard support of to 64 adapters. I don't think I even have half that many power outlets in my home.So what's the catch? Well, Powerline networks get a little trickier when you move out of the realm of the single family home. This is where the security issues begin.

The HomePlug standard has security features such as encryption built in but because their main goals seem to be ease of use and interoperability, most HomePlug devices have the same network name "HomePlugAV" or something similar. This makes it easy for people to 'plug and play' devices from different companies who are part of the same HomePlug standard. Since they have the same network name they will all talk to each other without any user intervention.

The main issue with all Powerline network devices having the same out-of-the-box default network name is when you live in an apartment, dorm, or other situation where the electrical wiring is shared. If two or more different apartments start using Powerline networking products with the same network name then they are essentially sharing their network with each other which could lead to all manner of security and privacy issues.

How do you implement the security features of HomePlug Powerline Networks to create a more private network?Change your Powerline network name

Most HomePlug Powerline network devices have a 'group' or 'security' button that will allow you to change your network's name. Usually this involves holding the security button down for s specified period of time to clear the default name and generate a new random network name.

Once the new network name is established, all the other powerline network devices must be given the new name so they can communicate with each other. Again, this is done by pressing the security button on one of the Powerline network devices for a certain number of seconds and then going to the other Powerline network devices and pressing their security button while the unit with the new network name is in 'broadcast new network name' mode.

Even though the HomePlug Standard is used by several manufacturers such as DLink,Netgear, Cisco, and others, the time you hold down the security button to accomplish creating and joining a network may be slightly different depending on the manufacturer of the HomePlug network devices you are using. Check your specific Powerline network device maker's website for details on how to create and join a network.

Use Powerline HomePlug scanning / configuration software to detect rogue devices

Some HomePlug Powerline network device makers have a software program that can detect what devices are present on your network and can configure them as well (provided you have the device passwords that are printed on each device).

If you only have two powerline network devices in your home and the software detects more than two, then you know that your network is mixing with a neighbors and that you should create your own private network by following the instructions above.

Slow HomePlug? Five Ways To Boost Powerline Network Speed

Powerline networking can deliver higher and more consistent throughput than wireless, but it can take some tweaking. These tips will show you how to improve your HomePlug network speed.

1. Upgrade to 200 Mbps PowerlineIf you still have original HomePlug (14 Mbps) or even

HomePlug "Turbo" (85 Mbps) gear and you're trying to use it to stream HD video, you're fighting a losing battle. Original HomePlug adapters yield only around 5 Mbps of usable throughput (Figure 1).

Figure 1: Linksys PLEBR10 throughput[from Linksys Instant PowerLine EtherFast 10/100 Bridge review]

While "Turbo" adapters are able to deliver best case (same room) speeds in the low 20 Mbps range, average room-to-room speeds quickly move down to 10 Mbps or so (Figure 2)

Figure 2: HomePlugTurbo Adapter Throughput results [from HomePlug Turbo Adapter Round-Up]

Both of these speeds are too low to support the 20+ Mbps required for 720p HD streams. But HomePlug AV (200 Mbps) adapters can deliver best case speeds of 60+ Mbps (Figure 3). Even when degraded by 50%, these speeds are fine for 720 and even some 1080p HD streaming applications.

Figure 3: ZyXEL PLA-400 throughput

2. Don't Mix HomePlug Adapter TypesAlthough implied by solution 1, I'll say it explicitly: get rid of older versions of HomePlug

adapters and standardize on 200 HomePlug AV. There are two reasons why this is a good idea. First, HomePlug AV can coexist with HomePlug and HomePlug Turbo, but not interoperate.

"Coexist" means that both flavors will work, but only with like adapters. (Actually original HomePlug and HomePlug Turbo will also interoperate, but with reduced performance). But "coexist" doesn't mean that the different generations of HomePlug gear will play nice.

Figure 4 shows around 60% reduction in HomePlug AV throughput when HomePlug Turbo devices become active at the same time.

Figure 4: HomePlug Turbo / AV Coexistence - HPAV first[from Zyxel PLA-400: Putting HomePlug AV into the game]

No interoperation means you won't get a connection between gear connected with HomePlug AV adapters and those connected with older types.

3. Don't Mix HomePlug and DS2

As is their way, consumer networking companies prefer to create their own branding for products, instead of emphasizing compliance with industry standards. So if you're looking for "HomePlug AV" in product names, you won't often find it.

Instead, you'll find some combination of "Powerline", "AV" and "200" in product names and, if you're lucky and look very closely, some reference to HomePlug AV in small print somewhere on the product box sides or back.

Unfortunately, there are two "200 Mbps" powerline networking technologies: HomePlug AV and DS2 (also sometimes known as UPA (Universal Powerline Association). As you might guess, these two technologies don't play well together. (An example of a DS2 / UPA product is NETGEAR's HDXB101 Powerline HD Ethernet Adapter kit.

Figure 5 shows what happened when I tried to run a pair of DS2 and a pair of HomePlug Turbo adapters that were plugged into my home's outlets at the same time. Note that I wasn't trying to pass data between the HomePlug and DS2 adapters, I was just trying to run them in parallel.

Figure 5: HomePlug Turbo and DS2 battling for bandwidth [From Corinex AV200 Powerline And CableLAN Set The Pace For Alternative Home Networking]

Figure 5 shows the two technologies battling so badly that neither could operate reliably, i.e. they would neither interoperate nor coexist.

I'm told that changes have been made so that DS2 and HomePlug adapters will now at least coexist and let each other operate. But you'll still suffer performance degradation if both powerline networking flavors are in simultaneous use.

4. Watch Out For AFCI Breakers

During previous HomePlug AV testing, I discovered an important source of powerline network signal attenuation. In the U.S., the National Electrical Code (NEC) has mandated the use of AFCI   (Arc Fault Circuit Interrupter) circuit breakers  to protect bedroom outlets for new residential construction as of January 1, 2002.

Figure 6 shows that AFCI breakers are easy to identify in your home's circuit breaker panel.

Figure 6: Regular and AFCI circuit breakers

Putting a powerline networking adapter on a circuit protected by an AFCI breaker can easily knock throughput down by 50% or more. Figure 7 shows a quick experiment with an IxChariot throughput test running between two Cisco Linksys PLK300 kit HomePlug AV adapters.

The plot starts with one adapter connected to the outlet just outside my office, which is protected by a normal circuit breaker, and the other adapter connected to an outlet less than 6 feet away inside my office, which is behind an AFCI breaker. I then moved the adapter outside my office to the same outlet where the other adpater was plugged in (inside my office), then back to the hallway outlet again.

Figure 7: AFCI throughput reductionEyeballing the plot shows throughput went from around 15 Mbps up to ~ 50 Mbps and

back again, which is ~70% change!

Fortunately, I found out from an Atheros contact (formerly from Intellon, which was acquired by Atheros) that all AFCI breakers are not the same. Here's what he said:

AFCI circuit breakers can harm HomePlug signals depending on the design of the breaker. If the design has an inductor in front of the power supply bridge, there is little if any impact on HomePlug signals. 

Square D and Eaton AFCIs have this arrangement and are very HomePlug-friendly; it is fortunate that these brands have a large market share. Some other manufacturers (such asSiemens) have a capacitor in front and this is detrimental to HomePlug signals.

You can include Murray AFCIs, which are in my home, in the "bad AFCI" list, too. I priced Square D replacements at around $50 each, so I haven't yet swapped out the Murrays! But all of my HomePlug test locations are no longer behind any AFCI outlets.

Note: The 2008 NEC expanded the mandated use of AFCI breakers to include hallways, family rooms, closets and many other areas. This isn't effective in all states, yet, but it is coming.

5. Find and Filter Noise sources

Electrical noise on the powerline has always had the potential to reduce powerline network performance. But it can be difficult to track down and its effect varies. But, once again, when noise does have an effect, it can be significant.

Noise that can knock down your powerline network throughput can come from things that may not be obvious. And some obvious sources sometimes don't have much of a negative effect.

In my tests, motor noise from hair dryers and power tools didn't seem to have much detrimental effect on powerline network throughput. On the other hand, I have found that light dimmers connected to halogen lamps can have an effect.

An innocent looking cellphone charger sitting in a kitchen outlet turned out to be the culprit that was affecting throughput testing in one of my test locations. I also found that my plasma TV sourced enough noise to prevent effective HD streaming via powerline to it.

The only way to find the sources that can be affecting your powerline network is to carefully look for them and then run throughput experiments using a tool like LAN Speed Test, or better NetStress. [see How Fast Is Your Network? Five Ways To Measure Network Speed].

Make sure you run a long enough test so that you get a good throughput average in each case. Some throughput loss can be intermittent and hard to find using a short test.

Once you find the offending noise source, you'll need to filter it. Fortunately, powerline adapter manufacturers are starting to address this by building filtered outlets right into the adapters.

I haven't yet tested NETGEAR's XAVB2501 AV+ 200 kit, which has filtered outlets. But I have found thatPlaster Networks IX2 Isolator  (Figure 8) was very effective in preventing my tiny little cellphone adapter from reducing powerline throughput.

Figure 8: Plaster Networks IX2 Isolator

It's a tad expensive at $25 and its form factor isn't ideal in some cases. But Corinex also makes a powerline noise filter (CXZCXPPWR)  that's cheaper, too.

The Future

Intellon's PowerPacket technology is compatible with wireless and HomePNA solutions, making power-line an ideal option to serve as the backbone for a multi-technology home network. In this case, consumers will not have to discard their existing network solutions in favor of a new standard.

The one common thread among all of the networking options is the need for power. While a wireless solution may indeed shun wires, its access point is still going to be plugged in at some point. That power cord, for example, can tie the wireless network into the home's overarching power-line network.There are two other networking technologies to discuss: phone-line and wireless networks.

How Phone-line Networking Works(de completat)

How Home Networking Works(de completat)

Case study: Extending wireless coverage in a huge home with powerline networking

Wireless networks can be a beautiful thing, or they can be an incredibly frustrating thing. In this case study we'll look at how powerline networking was used to extend wireless coverage in a very big log house with thick logs walls and lots of tile, where running cat5 cable was not an option. For those not familiar with powerline networking, rather than running cat5 network cable, you simply plug a network adapter in to the wall at each location where you want to transmit and it uses your home power cabling for network communication.

The subject in question for this case study was suffering from abysmal wireless performance. Laptops used upstairs would consistently drop connections, streaming internet radio (via Sonos) would constantly buffer, and the wireless printer in the study would work marginally at best. To try and fix the problem a Belkin F5D7132 Wireless-G extender had been put in to place, in extender mode. This appeared to work sometimes, but most of the time wireless performance was still extremely frustrating.

Before digging in to the problem and providing a solution, I figured I would look at all factors. This was a little over a year ago, so I had different options at the time. Price wasn't a concern, as long as it wasn't too out there. More of the concern was the log walls, the tile, and the robust construction of the house, with no possibility to run cat5 cable. I decided to make a diagram of what I was starting with.

Obviously having the 2 Sonos ZonePlayers on wireless when they are right next to the switch is senseless, especially since the homeowner likes to stream internet radio via Sonos. The wireless extender extending over wireless is painful too. It's halving the bandwidth for transmit and receive, plus it's on the same channel as the main router. Half the time it's searching for signal as it can't pick up the wireless signal. When it does pick up signal it's terrible. At the PC in the electronics closet I can get the full internet download speed with speedtest.net, upstairs on a laptop it will register at a tenth of what it is downstairs, that is, when I can get it to work. The Sonos network and router also conflict with each other at times, with the router on auto select for the channel.

The router in the basement electronics closet is another big bummer. The house is new, the owner didn't think of cat5 cabling when building as someone sold them on wireless, and they are pretty concerned with aesthetics. Not only that, but the wireless router is showing signs of age, sitting with my laptop 6 feet away from the router I'll see ping times of > 200ms and occasional timeouts. The wireless extender is on the main floor, in a strategic line-of-sight place in relation to the router that should be good for signal.

My proposed solution:

Replace the aging Belkin router with a Buffalo WZR-HP-G300NH on channel 6, which the FCC report shows is the highest transmit power

Add in a D-Link 8-port gigabit switch (they have nothing gigabit now, but it's cheap and leaves room for the future)

Put the 2 Sonos ZonePlayers on wired and get them off wireless, set Sonos to use channel 1 for their mesh network.

Get the NetGear XAVB2501-100NAS powerline network set and put one at the router and one at the wireless extender (I verified no AFCI breakers as they can greatly diminish powerline performance), so at least the wireless extender should be able to serve good wireless to the main level. Run the wireless extender in AP mode on channel 11.

Here is diagram of the end solution, subtle changes, but hugely effective.

So how well does this work? Extremely well... The figures below were taken with a Dell Latitude D630 laptop and Intel 5300 wireless card set in wireless G mode running XP, to a nothing-special Dell desktop running XP and a 10/100 Intel NIC, plugged in to the internet router. The wireless G and the 10/100 NIC are quite obviously the bottlenecks, and the reason for the figures. The figures were taken with LAN Speed test, which is good for a baseline, but can not be accepted as the absolute fact as it uses SMB filesharing to attain its numbers. This is even more obvious with the powerline figures actually being faster on read than wired in cat5 direct, so take them with a grain of salt, but they are good for baselines.

Transport Write speed Mb/s

Read Speed Mb/s

Wireless G to router (6 ft. from router) 30.98 28.62

Wireless G to extender, then over powerline to router (6 ft. from extender)

32.15 28.12

Laptop plugged directly in to powerline in place of extender, powerline direct back to

50.46 42.42

router

Laptop plugged directly in to same router as Dell desktop

86.28 36.11

Would I do anything different with what is available today? A few things... First, the Netgear powerline adapter to the Belkin wireless G extender is ugly for aesthetics, and it's only wireless G. To be honest, that's more than enough for the internet connection here, but it could be better. Today I might sell the homeowner on the Netgear XAVN2001 wireless-n extender. Maybe if Netgear wants to send me one I can put it through its paces and see if it can improve on what we already have?

I'm also a big fan of the Vortexbox and would probably try to point the homeowner in that direction due to its Sonos server capabilities and the CD ripping and album art downloading qualities. The XP has worked ok for them, but it has two problems. First, they also rent the place out, and renters somehow keep getting on to the box for internet browsing despite setting passwords. This leads to spyware and constant configuration problems. Additionally, the internet is a satellite internet solution as it's in a remote location, and even with the small amount of Windows updates, they often go over their monthly download quota when also streaming internet radio.

The gist of all of this is that using powerline networking can greatly improve your wireless coverage, and wireless extenders that are not hardwired in (either via powerline networking, MoCa, or cat5) just won't cut it. When at all possible I try to move whatever I can off wireless, so that things like laptop wireless usage can go off without a hitch. In the future I'd like to try a powerline networking switch for audio/video devices where running cat5 is not possible.

GERMAN AUTO COMPANIES SUPPORT POWER-LINE STANDARD FOR PLUG-IN CARS

Soon charging your electric car will be similar to hooking a computer to a home network.

(Credit: HomePlug Alliance)

The HomePlug Powerline Alliance announced today that German auto manufacturers Audi, BMW, Daimler, Porsche, and Volkswagen have agreed to support HomePlug's Green PHY standard for electric-vehicle charging technology.

HomePlug is a technology that turns electrical wiring into data cable, hence eliminating the need for a separate set of wires for networking. Currently the most popular application of the power-line technology is in HomePlug AV-based devices used for home power-line networking, such as the WD Livewire, or the Linksys PLK300.

According to the HomePlug Powerline Alliance, the power-line standard that the five German carmanufacturers--"after intense case studies and tests"--are supporting is "HomePlug's IEEE 1901 Profile Green PHY (GP)," which was finalized in June 2010 and enables faster networking speeds as well as support for Smart Grid. The HomePlug Powerline Alliance describes it as a "a low-power, highly reliable and cost-optimized power-line networking specification" that helps connect different "applications such as as appliances, smart meters, climate control, and plug-in electric hybrid vehicles" via the existing electric wiring.

This means that in the future electric-car owners will be able to easily manage and monitor their cars' power consumption and charging on the same IP network as other devices in the home.

BEST POWER-LINE ADAPTERS

Power-line adapters are devices that turn a home's electrical wiring into network cables for a computer network. They come in handy when you need to bring the Internet connection to a far corner in the basement where Wi-Fi signals can't reach. A power-line connection is generally also more reliable than a wireless connection. With speeds up to 500Mbps, it's also faster. Here is a list of five of the best power-line adapters or adapter kits on the market. Note that you need at least two adapters to make the first power-line connection.

Linksys PLEK500 Powerline AV2 Gigabit Network Adapter Kit

With stellar performance and support for the new HomePlug AV2 standard, the PLEK500 is an easy recommendation.

Trendnet Powerline 500 AV Nano Adapter Kit (TPL-406E2K)

The Trendnet TPL-406E is a fast way to extend your home network, while saving both time and money.

D-Link DHP-501AV PowerLine AV 500 Adapter Starter Kit

Attractive, affordable, and very fast, D-Link's PowerLine AV 500 Adapter Starter Kit DHP-501AV is one of the best available in its class.

D-Link DHP-540 PowerLine AV 500 4-Port Gigabit Switch

Compact, good-looking, affordable, and fast, D-Link's PowerLine AV 500 4-Port Gigabit Switch DHP-540 makes a great device that extends your network both via traditional cables and electrical wiring.

ZyXel PLA4205 500 Mbps Powerline Gigabit Ethernet Adapter

The ZyXel PLA4205 power line adapter is an excellent alternative to using regular Ethernet or Wi-Fi to connect more devices to a home network.

Netgear Powerline AV+ 500 Adapter XAV5501

If you want to get the best data throughput speeds out of your home electrical wiring and don't mind the oversize design, the Netgear Powerline AV+ 500 Adapter XAV5501 would make an excellent buy.

Actiontec 500 Mbps Powerline Network Adapter Kit

While not perfect, the Actiontec PWR511K01 for now offers the best value among power-line adapter kits on the market.

FAQQ. Does power line networking work with Macs?A. Yes. Starting with HomePlug 1.0, power line networking works just like Ethernet cables, meaning you can use it to provide a network for devices of any platform.Q. I have a power line connection at home. Can I add a switch to the far-end adapter to add more devices to the network?A. Yes. This is similar to using a power line adapter with multiple network ports, such as the  D-Link DHP-540   or the WD Livewire Powerline.Q. Can I add a second router to the far-end adapter to add more devices to the network?A. Yes and no, depending on the router.

Generally, if you connect the second router's WAN port to the power line adapter, it will create a new LAN at the far end, and devices connected to this second router (both wired and wireless if a Wi-Fi router is used) can't see devices connected to the first router. All devices, connected to both routers, can share the same Internet connection, however.

Some Wi-Fi routers, such as the Asus RT-N66U or RT-AC66U, can work as an access point (AP) and when set to AP mode their WAN (wide-area network) port will work like another LAN port. If you use one of these routers as the second router, all devices connected to both routers will be part of the same LAN network.Q. How do I use power line to extend a Wi-Fi network?A. You can either: 

1) Get a kit of two power line adapters with the second adapter having a built-in Wi-Fi access point, such as the NetGear Powerline XAVNB2001 kit or the ZyXel PLA4231 Wi-Fi Extender. Or,

2) Get a kit of two regular power line adapters and a separate Wi-Fi access point. After that, connect the Wi-Fi access point to the second adapter at the far end of the connection.

Utilizarea unui ADAPTOR POWERLINE Extender Wireless N 500Mbps(de completat)

Utilizarea unui ADAPTOR POWERLINE Ethernet Gigabit 500Mbps AV500(de completat)