Category: Feature Article

Feature Article: Multi-Building Home Networks

What is a multi-building home network

A multi-building home network is a home or other small network where network devices are used in at least two buildings on the one property. The idea is for the whole logical network to be pervasive in all or some of the buildings that are on that same property.

The network will end up comprising of multiple segments (physical network connections) that cover each building where network presence is desired. Then there are segments that exist to create a bridge for data to move between buildings.

What properties and situations is this kind of network relevant to

The situation where this network comes in to its own is where it is desirable to have the home office in another building such as a detached garage or barn, but also the same Internet bandwidth needs to be available in the home and the detached building. This is more prevalent with farms where the “office” is the barn and none of the farm business is transacted in the homestead.

The same situation can exist with properties where there is at least one cabin, bungalow or static caravan that is used for extra guests or older children. Here, it may be desirable to provide the same Internet access as what exists in the main house to these locations. This is important with older children who use these buildings as their private space for activities including playing online games. In a similar vein, the same situation may extend to the use of a cabana that is located by the pool or in the garden as a place to benefit from Internet access through the use of a portable computer.

Now that various manufacturers are making network appliances like Internet CCTV cameras or Internet-enabled games consoles that benefit from being part of a network, this concept of multi-building home networks is becoming a lot more relevant. Imagine being able to keep an eye on the valuables in the garage or livestock in the barn from a PC in the house; or the older son playing an on-line game on the Xbox 360 using XboxLive in the bungalow.

How does this kind of network operate

This kind of network consists of many different segments that exist to cover the areas being served as well as segments that exist to transfer data out to the area-specific segments. All the segments are joined using media-specific bridge devices like wireless access points, Ethernet switches, HomePlug-Ethernet bridges or simply the local-network connections of the typical wireless router.

This means that all network devices that are part of this network setup are on the same logical network or subnet. This means that if they ask for IP addresses,  they will get their IP addresses from the same DHCP server that is in the network-Internet “edge” router. They will also benefit from that router’s Internet gateway functionality and from resources made available to them by other network devices.

Techniques And Methods

Dedicated wire run 

The buildings may be linked by a direct wire, usually Category 5 / 6 twisted-pair copper Ethernet cable or fibre-optic cable. The fibre-optic cable is more expensive than copper-wire cabling, especially for smaller runs, but would suit installations where the buildings are a very long distance (3 kilometres) apart or there could be excessive electrical noise. On the other hand, copper-cable twisted-pair Ethernet can suit inter-building runs of up to 100 metres.

Both cables will need a dedicated run, which will typically require a trench to be dug between the buildings and the cable to be run in a conduit for best results. This work can be affordably done if you are running low-voltage communications cable like a telephone line between the buildings.

Each end of the cable run would need to have an Ethernet switch in the case of a copper-cable run or media converters in the case of a fibre-optic run. The Ethernet switches are just about a “dime a dozen” for a five-port or eight-port unmanaged 10/100Mbps unit suitable for small networks and a bit extra for Gigabit units. An existing switch that is part of your home network, such as the one built in to your router or used as a “hub” in your Ethernet-based home network can do the job equally as well as a dedicated switch. 

Wireless

This method uses a radio link as the means for data-transfer between the buildings. It is based on the use of 802.11a/g/n equipment, commonly known as WiFi equipment, which works at a theoretical raw data speed of 54Mbps for 802.11a/g and 248Mbps for 802.11n. The range where the speed will be maintained will depend on the wireless equipment used and the antennas (aerials) used with the equipment. Typically the bandwidth will taper off as the distance between the equipment increases.

Inter-building applications have typically used equipment that is capable of working with higher-gain directional antennas than what is typically supplied with the equipment and such equipment is typically installed outdoors with an Ethernet cable used for bringing data in to the buildings.

It can involve the use of “shared WiFi” where remote buildings are equipped with wireless client bridges that are pointed towards the wireless access point installed in the main building. This same method permits WiFi use by portable devices used in or near the main access point, but requires different SSIDs for access points used in remote buildings.

Another method is to use a dedicated wireless link for building-building data flow. This can be achieved through the use of multi-function access points that are set up as “wireless bridges”. This wireless link wouldn’t be able to be used by portable devices for wireless network access.

Yet another method that works with some wireless access points and wireless routers is to use Wireless Distribution System. It allows the member devices to become wireless-segment repeaters, thus expanding wireless segment coverage and becoming an Ethernet bridge for the data. Portable devices can roam amongst the stations as if they are moving around an “extended service set” collection of access points with a wired backbone.  At the moment, the setup doesn’t permit true fault-tolerant signal meshing without bandwidth starvation, but can do a fair “hands-off” job of extending the “extended service set”.  

Non-dedicated wire run 

This method uses wires that are used to provide an existing service to the building rather than a dedicated wire run. It avoids the need to spend money on costs associated with running that dedicated wire, such as trenching and conduit runs, while avoiding the need to dig up established landscape.

There used to be two methods based around this concept but the most common one would be the HomePlug system which uses the infrastructure that is used to provide AC power to appliances that are used on the property. It is often marketed as a “no-new-wires” backbone for establishing new networks but can be used as a supplementary segment for existing networks. This is typically promoted through the small “infill” access points like the Netcomm NP290W which plug in to the wall and provide extra coverage for an existing wireless network.

It can work effectively in most residential, small-office and rural properties because they are often wired to the one general-purpose electricity service from the head transformer. This is typically exemplified with the property having one “common-tariff” electricity meter accounting for all the “common-tariff” electricity used on the property. It may not work if any building, like a bungalow, has been metered separately because, in most situations, the different services may have been derived from different phases.

Some sites may, because of inter-building wiring distance, require the HomePlug segment to be pushed out further. This situation is typical of buildings that are used as a “go-between” wire point for other buildings or static caravabs. This involves the creation of extra HomePlug segments for the remote buildings.

This is achieved by the use of 2 HomePlug-Ethernet bridges connected to each other by an Ethernet patch cord or Ethernet switch and installed close to the building’s AC switch board or fuse box.

One of the bridges is configured to use the Network Password (segment identification name for a HomePlug network, equivalent to an SSID for a WiFi wireless network segment) of main segment, while the other uses a new Network Password representative of the new segment. Remote HomePlug devices use new Network Password.

The appropriate method

Working From Scratch

You may be building the outbuilding from scratch or doing extensive renovations to an existing building, which involves work with the electrical circuits in the building. This includes running AC wiring to and establishing AC circuits in an existing building that has no AC power. In this case, you may want to “cover all your bases”, especially if you are dealing with a garage, barn, bungalow or cabin where the building is going to be a point of activity. This means running a dedicated wire run between the main building and the outbuilding. The materials that you use may depend on your budget that you allocate for the project.

This option can work very well in making maximum value from your tradesmen who are doing any cabling work on the project. If cost is an issue, you may have to use HomePlug as your inter-building link.

Existing Buildings

For existing buildings, especially on properties where there is established landscape, you will need to use either a wireless or HomePlug link.

If you prefer to run a wireless link, it may be preferable to use wireless infrastructure hardware which works with third-party antennas and is capable of working outdoors.

HomePlug can also and has been known to do a more reliable job as a building-building link in this context than wireless. This is more true of buildings that are made out of metal such as the “quick-assemble” garages and sheds because the metal frame and / or walls do block or limit the transmission of radio waves.

Static Caravans

Typically these vehicles are capable of being moved around the property at a moment’s notice. Most of the time, these vehicles are hooked up to the nearest power outlet on the property using a long high-current low-resistance extension cord. This is often to enable use of interior lights and appliances that are plugged into power outlets that are installed in the vehicle. Also, this practice allows one to use the gas-electric fridge that is built in to the vehicle with it running off AC power rather than gas or the vehicle’s 12 volt battery.

A highly-reliable method of bringing the home network to these vehicles would be the HomePlug power-line link. This technology would be suited to the job because of the metal-based construction of the typical post-1950s caravan or campervan which can interfere with wireless inter-building links. The HomePlug access points like the Netcomm NP290W can work effectively in this situation by providing a strong wireless signal within the metal walls of these vans while using the power link as the data run.

Conclusion

As governments and Internet service providers make an effort to provide less-dense communities like the country and outer-urban areas with broadband Internet access, the idea of extending the home network beyond the main house on a large property will be very real. This article has explained how this idea can be achieved with the existing technology.

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