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1.4 Wired and wireless networks - Coggle Diagram
1.4 Wired and wireless networks
Types of networks
LAN
A LAN can be created to share data or hardware such as a printer or to share an internet connection. Also, all of the hardware for the LAN is owned by the organisation using it
A LAN is when computers or devices are connected over a small geographical are, such as within a home, a building or one site.
LAN - Local Area Network
They are wired with UTP cable, fibre optic cables or wireless using Wi-Fi
WAN
WAN - Wide Area Network
A WAN is when computers or devices are connected over a large geographical area. Some companies can also connnect several LANs together to creat a WAN.
Infrastructure between the LANs is hired from telecommumication companies who own and manage it.
The biggest WAN we know is the internet. WANs are connected with telephone lines, fibre optic cables or satellite links.
Hardware that connects a stand-alone to a LAN
Wireless access points
allow wireless enabled deviced to access the network without cable. WAPs can include a wirless router/switch that provides the functionality of all three devices in one.
A
router
sends data between networks. It is needed to connect a local area network to a wide area network. It uses the IP address on a device to route traffic to other routers
A
switch
sends data between computers on a local area network. It uses the NIC address on a device to route traffic.
Transmission media
Shorter connections between desktop computers and a switch are usually paired with
unshielded twisted (UTP) copper cable
. It's cheap, flexible and easy to install
Fibre optic
cable has a higher bandwidth than copper and suffers from less interference. Longer distance cable and wide area networks are usually connected with fibre optic cable.
A
Network Interface controller
-NIC- connects a device to a wired or wireless network connection.It uses a protocol to ensure successful communication
Factors that affect performance
Number of users
- Too many users or devices on the same network can cause the network to slow down if there is insufficient bandwicth for the data.
Error rate
- Less rerliable connections increase the number of errors that occur when data is transferred, resulting in data having to be present. The signal quality of wireless dependent on the range of the device.
Transmission media
- Wired connections give better performance than wireless connections.Fibre optic cable have a higher bandwidth than copper cables.
Bandwidth
- The amount of data that can be sent and received in a given tme. This is not a measure of how fast data travels,but how much data can be sent on the transmission media. Measured in bits per second - Often called the bit rate.
Latency
- The delay from transmitting data to receiving it. Latency is caused by bottlenecks in the infrastructure of the network.
Networks
Advantages of networks
Users can share files
Users can share peripherals such as printers, and connections to other networks, e.g. the internet
Users can access their files from any computer on the network
Servers can control security, software updates and backups of data
Communication with other people, e.g. email and social networking
Disadvantages of networks
Increased security risk to data
Malware and viruses spread very easily between computers
If a server fails, all the computers may not work
The computers may run more slowly if there is a lot of data travelling on the network.
Computers tham are not conected to a network are called stand-alone computers
A network is two or more computers or electronic devices that are connected together for the purpose of communication. They are connected my a wired medium such as cables, or by a wirelss medium such as Wi-Fi
Client-server network
A client-server network is managed by a server.The devices connected to the server are clients. A server controls the access and security to one shared file store, and also controls the access to the internet. A server can also manage printing jobs and provide email services.
Clients send requests to the server, e.g. asking for data, the server processes the request and responds. This is the client-server relationship
Pros
Its easier to keep track of the files as they are stored in a central location
Its easier to perform back-ups on
Its easier to update and install software
Its easier to manage network security, e.g. anti-malware software and user access levels.
Cons
It can be expensive to set up; and needs IT specialists to maintain the network and server
Server dependence - if the server goes down all clients lose access to their work
The server may become overloaded if too many clientss are accessing it at once
Peer-to-Peer network
In peer-to-peer networks all devices are equal, connecting directly to each other without a server. You store file on individual devices and share them with others.You may use a peer-to-peer network at home to share files between devices, or connect devices to a printer.
Pros
Easy to maintain - you don't need any expertise or expensive hardware.
No dependence on server - if one device fails the whole network isn't lost.
Cons
No centralised management - devices need their updates and security installed individually. Backups are also more complicated.
Copying files between devices creates duplicate files - it's easy to lose track of what's stored where and which files are uo-to-date.
Peer machines are less reliable and data may be lost if one fails
Machines are prone to slow down when nother devices access them.
The internet as a worldwide collection of computer networks
Domain name server (DNS)
- A DNS translates a website's domain name into its IP addresses. The internet has a network of domain name servers, meaning that you don't need to remember IP addresses to access websites - you can use domain names instead.
Cloud Storage
Pros of Hosting
Users can access the files from any connected device
Easy to increase how much storage is available
No need to buy expensive hardware to store data
No need to pay IT staff to manage the hardware
Cloud host provides security and backups for you
Cloud software will be updated automatically
The cloud
- The cloud uses the internet to store files and applications
Relatively recent the use of internet hosting is for the general storage of user files and also providing online software - this is cloud computing or simply,
The Cloud
. Its acts like an extension of a traditional client-server network where the user files are stored centrally on a network server.
Hosting
- This is when a business uses its servers to store files of another organisation. The traditional use for this on the internet is the hosting of websites.
Cons of Hosting
Need connection to the internet to access files
Dependent on the host for security and back-ups
Data in the cloud can be vulnerable to hackers
Unclear who has ownership over cloud data
Subscription fees for using cloud storage and software may be expensive
The internet is a network of networks - it's a WAN that connects devices and networks from all over the world.
Virtual Networks
A virtual network is an entirely software-based network. They are created by partitioning off some of a physical network's bandwidth to form a separate network.
Several virtual networks can exist on the same physical network. These networks all share the same hardware, making virtual networks more efficient than standard physical networks
Each virtual network has its own security, including its own firewall. This also means that virtual networks can only be accessed by using certain software or login information - other people could be using the same physical network and not have access to the same virtual network, or even know that it exists.
