This section looks at network principles such as what is a network, what components are used to form networks and what are some different structures of networks.
WHAT IS A NETWORK
When computer are connected together to share data this is classed as a network. One of the first computer networks was formed in 1969, this was a small local network connecting a series of computers within one room, over the following year computer networks became more and more common and started to cover larger and larger areas. In 1989 Sir Tim Berners-Lee first created what we now know as the the World Wide Web. Sir Tim Berners-Lee wrote web client and server models, worked on URL structure, HTTP (Hypertext Transfer Protocol) and HTML (Hypertext Mark-up Language).
A network is when two or more computers are connected together.
Remember that the World Wide Web and the Internet are two different things. The world wide Web is the protocols, language and webpages we access, whereas the internet is the network that provides a medium for the transfer of data.
There are many different types of networks each with their own purpose, some of which are listed below.
Local Area Network (LAN): A LAN is a network that connects devices within a limited area, such as a home, office, or building. It is typically used for sharing resources such as printers, files, and internet access among devices.
Wide Area Network (WAN): A WAN is a network that spans a larger geographical area than a LAN, typically connecting devices across cities, countries, or even continents. It is used for connecting devices that are geographically dispersed and for sharing resources over a larger area.
Wireless Local Area Network (WLAN): A WLAN is a type of LAN that uses wireless technology to connect devices within a limited area. It is commonly used in homes, schools, and offices to provide wireless internet access to devices such as laptops, smartphones, and tablets.
Personal Area Network (PAN): A PAN is a network that connects devices within a person's immediate proximity, typically within a range of a few meters. It is used for connecting devices such as smartphones, tablets, and wearable devices to each other or to a larger network.
Virtual Private Network (VPN): A VPN is a type of network that allows remote users to securely access a private network over a public network such as the internet. It is commonly used by businesses to provide secure remote access to employees working from home or while traveling.
Storage Area Network (SAN): A SAN is a network that provides access to high-speed storage devices such as hard drives and tape libraries. It is typically used by businesses to store large amounts of data that can be accessed quickly and easily by multiple users.
These networks have various topologies(the way there are configured) the main topologies covered at this level are Ring, Bus/Line, Star, Mesh and Hybrid.
A detailed introduction to networks by: Crash Course
NETWORK TOPOLOGIES
It is important that networks large and small use a standard approach to the configuration and protocols to allow for compatibility between network nodes and pave the way for easy expansion of the network.
BUS/LINE NETWORK: A Bus network, also known as a Line network is one of the most basic forms of network, easy and cheap to set up. The network has a simple single line connecting devices from the start of the network to the terminator or termination node. Due to the reliance on the one Line of data transfer a Line network can be reliable and can lack performance compared to other network topologies.
RING NETWORK: A ring network is very similar to a Bus network however instead of having a simple line that reaches a termination point the ring network joins the end of the line to the start of the line creating a ring.
STAR NETWORK: A star network has a central switch controlling the flow of data to the correct device. Because each node or section of the network branches out from the switch if there is a problem with one branch it is unlikely to effect other branches on the network. Star networks are generally fast and more secure than a Bus or Ring network.
MESH NETORK: A Mesh network are most frequently used in wireless networks, in a Mesh network each device is connected to multiple other devices on the network. In a full Mesh network each device is connected to every other device on the network. Because each device is connected to multiple devices this allows for various data transmission routes in turn aiding reliability because if one route has a problem then data can follow another route.
HYBRID NETWORK: A Hybrid network is a mixture of other networks, for example many schools have a star network stemming from the server room and then ring networks in the classroom at the end of each branch of the star network, this helps cut cost but still maintain high reliability and performance.
NETWORK COMPONENTS
ROUTERS: A Router forwards data between IP addresses, they are commonly used to route a connection between the ISP and the client. When webpages are requested the request is forwarded from the route externally and then when the web packages are receive the router routes the packet to the correct device on the network ACCESS POINTS: An Access point is used on a network to distribute network access to users GATEWAYS: A Gateway is used to connect networks that are operating on different protocols or architecture. SWITCHES: A Switch is used to direct data to its destination, networks contain many switches and data is passed through switch to switch until it reaches its destination. HUBS: Hubs provide a connection between multiple devices, hubs are not used as much as they used to be, since a hub do not manage the data that flows through it, it simply distributes it to all its outputs. Instead switches are now used more frequently, a switch does manage the data that passes through and directs it to its next location. Generally switches are more secure than hubs. BRIDGES: A Bridge is used to change the medium of transfer, for example in school network Cat5 copper cables are used inside building and optical cables are used to transfer data between buildings, Bridges are used to link the copper cables to the optical cables. WORKSTATIONS: A Workstation is a computer connected to the network NODES: A Node is any device connected to a network ISP: An ISP or Internet Service Provider provides users with a connection to the internet. SERVERS: A server is a large powerful computer that is used to manage devices and data flow on a network. It provides a connection to share resources and allows efficient device management such as updating all computers on the network. PROXY SERVERS: A Proxy server is like a normal server but has the additional feature of managing the data between the LAN and the WAN, the Local Area/Internal network and a Wide Area/External network such as the Internet. The Proxy serve provides a buffer between the two networks, filtering data and storing data so if many computers on the network requests the same data it can distribute from store rather than requesting the same data multiple times, helping network speed and security.
WHAT IS A MAC ADDRESS
A MAC address is a unique address that is hard coded into every machine with network capabilities to uniquely identify the machine. The MAC address is assigned at manufacture and cannot be removed or changed. The MAC address is 48bits and represented in HEX code for easy human reading, for example: 00:03:F6:E3:6A:3E The MAC address is often known as the 'Physical Address' of your computer.
REVIEW #CS201
1: Fill in the blanks. When a computer connects to the internet it is given a location, the location can be static or dynamic and is known as the ......................................... . Individual access to the internet is provided by an ....................................... and the user uses software on their computer called a ................................... to view web pages. 2: State the purpose of a MAC address. 3: State two differences between a standard server and a proxy server. 4: Draw an illustration of star topology. 5: Give two advantages and two disadvantages of using a star topology. 6: Give two advantages of setting up a LAN. 7: A disadvantage of setting up a LAN is the cost, give two other disadvantages of setting up a LAN. 8: Describe how a VPN works to hide a users physical location.
