1.3 Computer networks, connections and protocols Flashcards
LAN
Local Area Network - Small geographic area. All the hardware for the Lan is owned by the organisation using it. Wired with UTP, fibre optic cable or wireless using routers and Wi-Fi access points.
WAN
Large geographic area. Infrastructure is hired from telecommunication companies who own and manage it. Connected with telephone lines, fibre optic cables or satellite links.
Client-server network
A client makes requests to the server for data and connections. A server controls access and security to one shared file store. A server manages access to the internet, shared printers and email services. A server runs a backup of data.
Peer-to-peer network
All computers are equal. Computers server their own files to each other. Each computer is responsible for its own security and backup. Computers usually have their own printer.
Wireless access point
A networking hardware device that allows a Wi-Fi device to connect to a wired network.
Router
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.
Switch
A switch sends data between computers on a local area network. It uses the NIC address on a device to route traffic.
NIC
Network Interface Card - A computer hardware component that connects a computer to a computer network.
Transmission media
The physical media over which data is transmitted, e.g. Twisted copper cable, fibre optic cable etc.
The Internet
The internet is a worldwide collection of interconnected computer networks. It is an example of a WAN, albeit the largest one that exists.
DNS
Domain Name System - The Internet’s equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses. This is necessary because, although domain names are easy for people to remember, computers or machines access websites based on IP addresses.
Hosting
Websites stored on dedicated servers. Reasons include: Websites need to be available 24/7. Accessed by thousands of users at a time. Strong protection from hackers. They need an IP address that doesn’t change.
The Cloud
Remote servers that store data that can be accessed over the internet.
Web server
A program that uses HTTP(Hypertext transfer Protocol) to serve the files that form web pages to users, in response to their requests, which are forwarded by their computers’ HTTP clients. Dedicated computers and appliances may be referred to as Web servers as well.
Client
A client can be thought of as computing device which requests or is using the services from some remote / connected server.
Network topology
The physical or logical arrangement of connected devices on a network e.g. Computers, switches, routers, printers, servers etc.
Star topology
Computers connected to a central switch. If one computer fails, no others are affected. If the switch fails, all connections are affected.
Mesh topology
Switches (LAN) or routers (WAN) connected so there is more than one route to the destination. E.g. The internet more resilient to faults but more cable needed.
Advantages of ‘The Cloud’ are:
Advantages: Access anytime, anywhere from any device. Automatic backup. Collaborate on files easily. No hardware required.
Name a few types of servers that have different services
Web server, database server, DNS server, email server, file server etc.
Disadvantages of ‘The Cloud’ are:
- Lack of control. Handing over of data and information.
- Bandwidth problems. All depends on speed of connection.
- Relies on a stable internet connection.
Advantages of a Star topology:
- Cheaper than mesh topologies.
- One cable breaking will only affect its corresponding node.
Disadvantage of Star topology:
- The switch is a huge point of failure - if it breaks then all computers lose their connection to the rest of the network and the internet.
Advantage of Mesh topology:
If you get a break in a cable, traffic can be rerouted via another cable.
Disadvantage of Mesh topology:
Very expensive as lots of cabling and switch hardware is needed.
Advantages of Partial Mesh topology:
The same benefit as a full mesh network to a slightly lower extent. Cheaper than a full mesh network.
