Please enable JavaScript.
Coggle requires JavaScript to display documents.
Computer networks (Types of Networks (Local area networks (A local area…
Computer networks
Types of Networks
Local area networks
A local area network is usually within one building or does not spread onto a large area.It consists of a number of computers connected to hubs or switches.The hub usually is equipped with a router and modern to allow the LAN to connect to the internet
Advantages
-The sharing of rescources
-Easy communication between users
-A network administrator to control and monitor all aspects of the network.
Disadvantages
-Easier spread of viruses throughout the whole network
-The development of printer queues, which can be frustrating to operate
-Slower access to external networks
-Increased security risk when compared to stand-alone computers
-The fact that if the main server goes down, everything will go down with it.
Ring networks
Ring networks are becoming less popular.Every computer in the network is connected in a ring, including the server. Data is transmitted around the ring and each computer only removes the data which is relevant to it allowing each computer to send and receive data since they all have unique identification.
Advantages
-Ring networks work well under heavy loading
-It is possible to create a very large networks using this topology
Disadvantages
-If there is a fault in the wiring between two computers then the whole network will fail
-Adding a new device or computer to the network can be difficult since it has to be placed by two existing devices.
Bus networks
Computer which is connected to a common central line.Data travels along this line to computers.
Advantages
-It is easy to add a new computer to the network
-If one device fails, it does not affect anything
-Bus network doesn't need a hub or switch to operate and requires less cabling than others therefore being more cost efficent.
Disadvantages
-It is difficult to isolate a computer on the network
-If the central line has an error then the whole network fails.
-This is becoming an increasingly outdated technology for network design.
-Its performance worsens as more computers are added.
Star networks
Star networks is devices getting connected via a central hub or switch.Data is sent to the hub then sends it to the computer requesting it through a cable.
Advantages
-If one computer or device fails, then the rest isnt affected
-Problems on the network are easy to identify and work can be carried out on a faulty device without affecting the rest of the network
-It is easy to expand the newtork
Disadvantages
-If the central hub breaks down. the whole network crashes down.
Tree networks
A tree network has a central line connecting together a series of star networks.The server is also connected to the central line.The advantages and disadvantages are the same as bus and star networks.
Network devices
Modems mean a device which converts computers' digital signal into an analogue signal for transmission over a existing telephone line
-
-
-
Routers are often used with large companies when one computers in one network want to communicate with the computers in one of the other networks
Wireless LANs [WLANs]
WLANs are similar to LANs but it is wireless. It provides internet communications over short distances but wireless.Examples are:radio and infared signals.
Devices,known as access points, are connected into the wired network at fixed locations because of the limited range, most commercial WLANs need several APs to permit uninterrupted wireless communications.
Advantages
-All computers can access the same services and resources
-There is no cabling to individual computers and devices so safety is improved
-The system is flexible, since users can move their laptops from their desks
-Adding new computers and devices are easy and costs are reduced
Disadvantages
-Security is a big issue as someone can easily hack your device
-There may be problems of interference which can affect the signal
-The data transfer rate is slower than LANs
WI-FI
Wi-fi refers to any system where it is possible to connect to
a network. Wi-F
systems rely on some form of AP which uses radio frequency to operate.Wifi hotspots are places where you can access WIFI. They exist t in airports, hotels and internet cafes. It is possible to logon WI-FI hotspots unless they are protected by passwords.Software exists which can be loaded to a laptop which then searches for unprotected wifi systems.
Wide area networks
Wide area networks is basically a formed by a number of LANs being connected together by a router or a modern
Bluetooth
Bluetooth is an example of wireless personal area networking technology.Spread spectrum transmission is used to provide wireless links between mobile phones , computers and other handheld devices that allow connection of the internet.