Types of Device
Switches are very similar to hubs with the exception of containing the ability to read the packets received. This means that the device gets the packets, reads them and only forwards them to the appropriate attached device. Because switches can read the packets instead of just sending them on to all devices, it means they operate at the data link layer, layer 2.
A repeater is a simple device that boosts the signal so that it can travel much greater distances or avoid “obstacles”. They operate at Layer 1 of the OSI Model.
A hub is simply a device that connects parts of LANs together. They are multiport devices and copy the data received from one port onto the other ports. Hubs operate at the physical layer (level 1) as they operate by using simple physical transmissions to send data from one device to the next. Hub’s only use bits to send the data and cannot understand anything above bits on the OSI model.
Bridges and Routers are quite similar – they both direct traffic between two devices. A bridge will connect hardware together using hardware assigned MAC addresses. Bridges are a layer two device. This means that bridges cannot determine the type of network that they’re running on.
Routers, like hubs and switches, connect together multiple networks. Routers use headers and forwarding tables to create and send packets to determine the path through the networks and this means they operate at level 3, the network layer.
Gateways are used to “interface with another network that uses different protocols.” This allows two different systems using two different protocols to work with each other. Gateways operate at all levels of the OSI model. Gateways can handle what can access the network and what cannot and helps to control the applications that require networks to run.
Local Area Networks are very easily constructed with the use of these devices. LANs are quite easily created using; routers; hubs, switches, bridges; gateways and repeaters as well as UTP wiring.
The network consists of many devices. Depending on the purpose of the network; the devices attached to it will be different. A network that needs an external connection will include a router as this makes external access possible but Local Area Networks could use hubs, switches or bridges to connect parts of the network together. Gateways are also a possibility when connecting devices together that don’t necessarily know how to interface with each other.
Copper Twisted Pair Cable
Short to medium distance networks
* Can have problems with interference.
* Cheaper than newer types of technology.
* Main different types used for many varied uses.
* Created when two conductors are twisted together.
* More twists desirable – less interference.
TV, broadband and radio
Between 750ft and 1500ft dependant on cable type
* Uses insulation to carry the signal with the least amount of interference.
* A lot of research has gone into creating the most effective systems – those with space carry the signal better.
* Extremely cheap and easily available.
* Two types – rigid and flexible.
Fibre Optic Cable
TV, broadband and radio
160km when used with amplifiers.
* Light is sent down an optical cable.
* Created in the 1980’s.
* Replacing older systems.
* Much more reliable – less chance of interference.
Sharing a connection or resources across a short distance network
* Standards known as 802.11. G and B are the most common.
* Requires a wireless router to project the signal to a computer or other electronic device.
The internet and WWW.
Worldwide – signal sent across many satellites.
* Bandwidth of 34 Mbit/s
* Ability to send large amounts of information across the world.
Internet, mobile phones, networks, TV and many other uses.
Line of sight unless amplification is used.
* Transmitter and receiver need to line up.
* Used in many ways – 802.11g is one example of a microwave.
Importance to Small Office, Medium Business and Large Company on a scale of 1 to 3.
Choosing any type of network equipment is a very important decision. Each and every organisation and office will be unique in its requirements.
Speed is a necessity for some offices; usually those that rely heavily on the network for day to day activities. The more computers that are connected the network, the more bandwidth the equipment must be capable of providing. A single slow device on the network is going to slow down everything as networks are only capable of running at the speed of their slowest device so ensuring that all devices are capable of carrying the correct speeds.
Other networks are not going to need high speeds such as those that only connect just a few computers together, or those that will only connect to the network occasionally.
The size of a device is not necessarily all that important for most businesses if they have the room to keep it. For a medium to large business, finding space to place your hardware is unlikely to be a major problem. Smaller businesses will usually have less space to place their hardware, particular the type of safe and secure space that is required by such important devices. Finding a device that is small enough to be stored but still fulfils other requirements is required.
The cost of a device is not going to be all that important to larger businesses; spending a lot of money on a useful device seems only natural. But when spending the vast majority of a network’s budget on a single device, cost definitely becomes a factor. It must be the right device and it must do the job it’s required to do but it should also be at the right cost to the business.
Connectivity is heavily dependent on the number of computers that are being connected as well as what services the network is trying to provide and how the devices are going to be connected.
The device that is eventually chosen must be a combination of the most important needs of the network. Placing a value on each of these factors should suggest the device that is needed.