Networks & Communications
Just about every house has a network of some sort it, whether it be a mains electricity network or a telephone network with master socket and extension lines. With the arrival of the Internet, many homes now have a data network connection to them and some form of wireless of wired computer network within them. The voice communications elements are covered in more detail in the communications section.
When undertaking a new house build, advance planning of the networks within it will make life simpler and cheap in the long term. Consideration needs to be be given to the networks to be installed and the usage made of them.
Some of the wired networks often found in a home are:
- Mains electricity network used to provide 240v ac (in the UK) to sockets and appliances. In some homes 'power line' adapters are used to provide a data network over this same wiring.
- PSTN / telephone network for phone lines and extension sockets. These can also be used to provide a broadband data connection to a house using ADSL technology.
- Security / burglar alarm systems using a 6 or 8-wire network to door sensors, PIR sensors, etc.
- Co-axial cable networks for TV aerials, satellite dishes and TV signal distribution around the home.
- Ethernet computer networks for PC's, printers, network storage, set-top boxes, etc.
- We are currently using a optical fibre Ethernet bridge, which allows long distances to be bridged with a fibre network and provides an RJ45 connector with standard Ethernet at each end. This is great for electrically noisy environments and for connecting two buildings (e.g. house and garage).
Internet Network Connections
In an ideal world, a service provider would deliver a reliable IP network connection to your home and it would terminate with a socket on the wall, providing Gigabit Ethernet connectivity. This would enable fast data connectivity in both directions and would require no powered network terminating equipment in your home. All you would require is an Ethernet switch to distribute the connectivity around your home and a wireless access point if required.
In reality, most homes are left with the choice of one of the following:
The Internet has progressed so quickly that it is hard to believe that some people still use a dial-up network connection, with a modem sending data over a normal telephone line. This is old technology though and is unlikely to survive into the next decade.
ADSL is currently the most popular form of Internet connection in the UK and coverage and the underlying technology are improving all the time. The A in ADSL stands for asymmetric, which means that traffic faster flows quicker in one direction. It is usually the downlink speed that is higher and typical speeds are 1Mbps downlink and 512Kbps uplink. The speed available is a function of the distance from the telephone exchange and the quality of the copper wires between the house and the exchange. This means rural areas get much lower speeds.
Advances in the technology mean that ADSL2 and ADSL2+ can provide higher speeds but, the basic laws of physics mean that speeds won't improve much above 20Mbps uplink and 3Mbps downlink and that's why fibre networks connections are now seen as the way forward. Fibre also removes the limitations due to the distance from the exchange.
Fibre To the Cabinet (FTTC)
FTTC (also called Fibre To The Curb) currently provides speeds around 40Mbps downlink and 10Mbps uplink, thought these speeds are continually improving. We have BT Infinity in our current home and 40Mbps downlink and 10Mbps uplink. BT is rolling out updates to increase this to 80Mbps downlink and 20Mbps uplink (BT Infinity 2).
Fibre To the Premises (FTTP)
FTTP currently provides speeds of around 100Mbps downlink and 30Mbps uplink. We also have this technology, in parallel with our FTTC network connection. We get speeds of 100Mbps downlink and 50Mbps uplink. The technology is capable of much more though and 300Mbps downlink speeds have been proposed. Here in the UK, FTTP means you have a direct fibre connection from your home to the local exchange.
Optical Network Terminal (ONT)
The ONT is the device that converts the signals coming over the optical fibre into electrical signals that can then be passed into a modem/hub.
Wired IP networks are physically more secure than wireless networks and provide the fastest speeds. There are various cable standards but they are generally based around Ethernet. There are various cable specifications used:
Cat5 is basically obsolete now and it is very unusual to find Cat5 cable still for sale. This cable supports networks of 10 to 100Mbps.
Cat5eCat5 enhance or Cat5e is used for 'Fast Ethernet' networks up to 1000Mbps (or 1Gbps). Most devices on the market have network ports that support speeds up to 100Mpbs. Cat5e is now the most common type of network cable available and there a many more device emerging that can support Gigabit Ethernet. Not all devices supports wired networks at these higher speeds. Very few laptops have network interfaces that support Gigabit Ethernet but many NAS devices do.
With 100Mbps and faster Internet connections now appearing, the local network in your home could be the bottleneck in the future. This is why Gigabit Ethernet is slowly replacing it in consumer applications but, it is far from widespread. In our home we have wired up our current house with Cat5e cable in order to support Gigabit Ethernet.
Cat6 cable is a fairly recent standard and specification to enable network speeds up to 10Gbps. The price differential between a 300m drum of Cat5e cable and the equivalent Cat6 cable is only about £20 now. If we were to buy any more Ethernet cable we would use Cat6 in the future and would also use it in our next home.
Cat6 faceplates and sockets are much more expensive and currently very hard to justify.
Power Over Ethernet (POE)
Power over Ethernet is another advantage of wired networks and allows a device attached to the network to also draw power from it (e.g. an IP camera).
The downside of wired networks is that retro-fitted them to 'brown field' sites (existing homes) can be troublesome, requiring installation and redecoration. This is why it is always better to install too much cable in a new build than too little. Cable is cheap compared to the time and effort required to retro-fit it at a later date. Not all of the cables need to be wired up to face plates initially and this can be done as more are required. Twin-port faceplates can also be used initially and swapped out with quad-port face plates later, if required.
Given the choice, our advice is:
- Always use wired IP networks wherever possible. They are more reliable, more secure and provide better performance.
- Use the best performance cables you can afford. We have currently wired our house using Cat5e cable to enable Gigabit Ethernet.
- Run more cables than you think you need to each socket. Cable is cheap compared to the time and effort required to add them later. Typically we would run 4 cables to each wall plate. If nothing else you can use the spare cable to pull through a faster one later.
- Do anything you can to make the cable runs direct, smooth and easy. Typically we have installed ducting for all cables where ever possible.
- Cables have a minimum bend radius. Optical cables are the future and will have larger bend radius limitations. Larger, smoother ducts with radiused junctions make adding new cables much easier.
Network ports in rooms are usually exposed via a single or double width wall plate and these can have from 1 to 8 RJ45 sockets. The sockets used on these faceplates are often separate modules and need to be chosen to match the Ethernet cable and network speed you plan to use.
All of the home network points are usually wired back to a central point and are then exposed via a patch panel. These are often mounted in a 19" rack cabinet or a smaller wall cabinet. This provides more flexibility.
In practice, it is cheaper and easier to terminate all cables with a RJ45 plug directly, so that they can be plugged straight into a switch. This removes connections and thus generally improves reliability. It is also cheaper. If using a patch panel, then patch cables are used to then connect patch panel sockets to the switch sockets.
We are currently using the Netgear JGS524 24-port Gigabit Ethernet switch shown above in our loft. We also have an 8-port switch under the TV as we have been unable to route enough cables to this location so far. In addition we have a 'mission critical' 8-port switch with POE capability in our Home Control System (HCS). This is used for key security components and IP cameras. It is powered via our 12V UPS.
It is important that all ports and cables are wired up correctly and we have adopted the T-568B wiring convention in our home.
We also use an Ethernet cable test tool. This makes it very easy to test your wiring and connections.
Wiring and ducting is also covered in the wiring section.
Wi-Fi has improved massively in recent years with claimed speeds increasing from 11Mpbs (802.11b), to 54Mbs (802.11g) and 802.11.n claiming 300-600Mbps, depending on the number of radios and the radio frequencies used. The latest standards such as 802.11ac should provide wireless speeds as high as 3Gbps.
We have used the word 'claimed' for good reason. In the real-world environment of your home the theoretical speeds quoted are never achieved though. There are several reasons for this including:
- Many devices don't have the hardware to drive the networks at these speeds. As an example the iPhone 4 will max out at 17Mbps regardless of the wireless network speed.
- The wireless signal is weakened by distance and objects in between the radios, e.g. walls, ceilings, etc.
- Interference from other Wi-Fi devices, networks and other technologies and devices in the home, e.g. microwave ovens and baby monitors.
- Inference from other networks close by on the same frequencies and channels.
- Other devices using the same network.
To overcome some of these problems the Wi-Fi hubs/routers are becoming more intelligent but the bottom line is that as more people use Wi-Fi and more devices get connected to the networks, the more congested the bandwidth becomes and the lower the performance for all.
From a home security and automation perspective, we don't consider Wi-Fi to be reliable enough or secure enough to use and opted for wired networking by default. We don't see this situation changing in the foreseeable future.
802.11ac is an enhancement of 802.11n that has recently been included in some routers (such as the BT home Hub 5).
Wireless Gigabit Alliance (WiGig) is an organisation promoting the adoption of multi-gigabit speed wireless communications technology operating over the unlicensed 60 GHz frequency band. This implies a relatively low power and thus limited range, shorter than current Wi-Fi standards. 10m line of sight is the claimed maximum so far. Introduce barriers and walls and it will be less. It is thus complimentary to Wi-Fi and is certainly not a competitor to 3G and 4G networking. One of the key applications envisaged for WiGig is wireless high-speed video transmission, e.g. wireless HDMI.
WiGig has been designed as a low-power technology and claims to be five times more energy efficient than Wi-Fi. It uses beam-forming to focus the radio beams for best performance, reducing congestion and effectively pointing the radio signal where it needs to go.
There is a very good TED talk on this subject:
Li-Fi has been in the news again (October 2013) after a a team of researchers in China
Power Line Communications
power line communication carries data over the cables in your home used to distribute mains power.
Power line adapters typically come in pairs. One is plugged into the mains power network near your router and is connected to it via an Ethernet cable. The remote end is also plugged into the mains power network and then also connected to your device using an Ethernet cable. Typically these are often used to network a Set-Top Box (STB) or Personal Video Recorder (PVR). It is possible to use a switch at the remote end, to connect multiple devices.
You can use more than two powerline adapters but the standards have evolved over the years and you need to ensure different brands and models are compatible.
Power line can work well in many homes but, it is sensitive to the layout of the wiring, the devices plugged into the power sockets and the electrical filters and circuits used within them. Whilst running technology trials, we have seen many homes where this technology simply will not work or has poor performance. The rated speed of these devices is the maximum theoretical speed possible under ideal conditions. In real-world installations the speeds achieved will be a lot lower than the quoted speed rating.
Some adaptors have a mains pass-through socket, which effectively gives you back the mains power socket that the adaptor would otherwise be occupying.
Do not use the default passwords on powerline adapters. You may well find that your connect to a neighbours network, if they use the same devices and same default passwords.
Modems, switches, routers, hubs, etc. all require power. This means that if you want to keep the network operating when the mains power is removed (i.e. a power cut), then you need to maintain this power using a Uninterruptible Power Supply (UPS). In our home we have installed our own 12V DC power network to achieve this.