Routers and Gateways
Routers
Routers are designed to connect subnets together which will have a set of IP addresses which are identifiable to that local subnet (e.g. 192.168.35.2, 192.168.35.5 these are two devices connected to the same subnet).
Gateways
A Gateway is designed to interface with another network that uses different protocols. A Gateway may contain a protocol translator, impedance matching devices, fault isolators, signal translators and rate converters.
Chapter 5b
How to Directly Connect Two Network Components
This section explains how two wired devices are connected over a LAN and their operation and performance, such as range, ease of installation, cost, convenience and security.
The two devices will be a Computer running Windows Vista Home Premium 32bit and a NETGEAR Wired Broadband Router DG834. This will also explain how they will be connected to the internet.
Scenario
A family has just bought a new computer with Windows Vista Home Premium on it and a new NETGEAR Wired Broadband Router DG834 as they want to be able to connect more devices in the future, such as a Windows Media Centre Extender so they can use their PC as a digital TV receiver and recorder. They have called you in to set up their devices to work efficiently. They want you to explain what you are doing so they can learn how it all works.
How to Set Up the Network
Firstly you will need at least once Ethernet cable and also a telephone cable with a RJ11. These generally come with the router. If not, you can buy these cheaply from any good computer shop. If you are connecting the router to the internet then you need to buy ADSL filters, these are little boxes that plug into the telephone line to split the DSL data and the telephone data so you can have an ‘always on’ connection. These have to be installed in every telephone socket that has a phone or sky box or anything else that uses the telephone line connected to it. If the socket is not in use then it does not need a filter. Once you have completed this step, you can then start connecting the router and computer together.
The first thing your computer needs is a Network Interface Card (NIC) that is designed to use Ethernet (RJ45) cables. New computers come with them preinstalled now or they are built into the motherboard so the computer in this scenario already has a NIC. Connecting the router and computer is a very simple process because all that needs to be done is the simple task of plugging the cable into the NIC in the computer and the other end into the router. When the router and PC are turned on, the computer will automatically recognise the router and will join the network. The operating system on the computer will ask you what type of network it is, if it is a private or public network. This is a feature of Windows Vista which allows it to make the correct security adjustments.
Now that the router and computer are connected to the network, you need to plug the RJ11 telephone cable into the port in the filter nearest the router and into the back of the router. Then, if the Internet Service Provider has activated the line, the router will connect to the internet, providing access to the computer and all other devices that will be connected in the future.
Operation and Performance
Range
The range of a wired connection varies on the length of Ethernet cable you buy. Also the range is limited by the structure of the house, for example, if you want internet in a room that you can’t get the cable into because the wall can’t have a hole drilled in it for example, then that limits the range.
Ease of Installation
This is very easy to install if everything is being situated in the same room, if the telephone box is situated in another place or the computer is situated in another room, it can be slightly trickier to install because holes will have to be drilled to feed the cable through.
Cost
The cost of a Wired LAN is relatively cheap because it is an old technology that is readily available, wired routers are cheap as well as the cables so you don’t have to spend much money to make a home network. Also if you only wish to connect one computer to another computer, you only have to pay for one Ethernet cable. So depending on the type of network you want to produce, the cost will be varying. Also the size of the network will determine the price.
So in this scenario, the cost of the items would be approximately £102.
Convenience
Having a Wired LAN can be convenient in the means that it is easy to install and is relatively inexpensive but the inconvenience about having a Wired LAN is that you may be unable to get a wire to a computer because a wall is unable to be drilled through or the wire isn’t long enough to reach the computer.
Security
Security is a major concern for a lot of people using a Wired LAN and the Internet. It is important that a network is secure so data cannot be stolen or accidentally leaked. Identity Fraud can be committed over the Internet as well so good security is a must. Also a good level of security will help to protect the computers from viruses, malicious code and other things such as attacks such as the Denial of Service attack, which is normally seen on web servers.
When using a router such as the one being used in the scenario, there will be a built-in firewall offering basic protection. It is important that all computers on the network have an anti-virus (e.g. AVG Free), firewall software (e.g ZoneAlarm) and a form of spyware and malware detector (e.g Spybot).
As it can be difficult to monitor a child’s access to the internet, it is important that awareness is raised of internet safety and also if you want to make sure that your child is not going on websites that they shouldn’t be, it is best to keep the computer in the living room where supervision is possible.
Chapter 5c
Wired and Wireless Data Transfer, Which is Better?
Continuing the scenario in Chapter 5b, you have now been given the choice of installing a Wireless or Wired LAN within the house depending on what you think is the best. Due to the way the house is laid out and how the family want their computers you have come to the conclusion that Wireless LAN would be more effective for the family and their requirements and wants. They want to have one computer upstairs in one bedroom, one computer in their living room and also a laptop that they can take around the house as well as a Media Centre Extender in the living room. The family have asked you to explain to them the data transfer differences between Wired and Wireless LANs. You will provide them with a written report which is written for someone who is not as technically adept as yourself.
Wired Data Transfer
Wired LANs (Local Area Connections) offer greater performance over a Wireless LAN because a modern Wired LAN can offer a theoretical 100Mbps (Mega Bits Per Second) whereas Wireless LAN can only achieve a maximum of 54Mbps. The speed provided by Wired LAN’s is sufficient for gaming, file sharing and high speed internet access. With Wired and Wireless data transfer, the speed can be affected by the number of clients accessing the network at any one time, so if the network traffic is high because there are a lot of people using the network on a school or business network, you will find that is runs slowly. Also with a Wired LAN, theoretically it is harder to intercept data from a Wired LAN as it is all running through cables. Firewalls are a main priority with Wired LAN’s. Hubs and switches don’t have built in firewalls so software firewalls such as the above mentioned ZoneAlarm is important. But Broadband Routers do come with built-in firewalls.
Wireless Data Transfer
With Wireless Data Transfer, the rate of transfer is slower than Wired LAN (54Mbps) but allows much more freedom around a house or business. For example, in a house, you can have a laptop that you can take into the garden and surf the web while sun bathing or if you have a games console plugged into your TV, you don’t have to have a really long wire connecting it to the router. There are some disadvantages though, if more wireless devices connect, the performance decreases and if you are further away, the performance will also decrease. Wireless LANs are suitable for File Sharing and Printer Sharing but not gaming or anything that uses the network heavily.
Theoretically, Wireless LANs are less secure as the signals travel in the air and can be intercepted but this is rarely seen being practiced. It is important that security on the Wireless LAN is enabled to protect access from unauthorised users, so this would be using WPA or WPA2 security.
For the family, because of their needs, it is best to use a Wireless LAN which will then allow them to have a Media Centre Extender in their living room, have a laptop that can be used anywhere in the house and a PC which will be upstairs in the office/study.
Josh Hancock Unit 8: Communication Technology Page of
