1.3 Computer networks, connections and protocols Flashcards
2 types of networks
LAN (Local Area Network), WAN (Wide Area Network)
3 features of LANs
Connected over a small geographical area located on a single site, hardware owned by the organisation using it, wired with UTP cable, fibre optic or wireless - Wi-Fi
3 features of WANs
Connected over a large geographical area - connecting LANs together, connected with telephone lines, fibre optic cables or satelite links, expensive to set up
5 factors that affect the performance of networks
Bandwidth, number of users, transmission media, error rate, latency (delay)
Define client-server model
Have one or more central computers or servers that hold and manage recourses. A server controls access and security to one shared file store.
3 advantages of client-server model
Easier to manage security files / take backups of all shared data / install software updates to all computers
4 disadvantages of client-server model
Expensive to setup and maintain, requires special IT specialists to maintain, server is a single point of failure, security-cyber-attacks
Define peer-to-peer model
Connects computers so that each computer shares all or part of its recourses. A peer is a computer on a network and is equal to all other peers.
4 advantages of peer-to-peer model
Easy to maintain, specialist staff not required, no dependency on a single computer, cheaper - no expensive hardware required
3 disadvantages of peer-to-peer model
Less secure, manage own backups / security, difficult to maintain a well-ordered file store - file duplication
Wireless Access Point tasks
Allows wireless-enabled devices to access the network. It avoids the need to install cables, so it is more convenient.
Routers tasks
Sends data between networks and is needed to connect a Local Area Network to a Wide Area Network. Can form a LAN by connecting devices within a building and makes it possible to connect different networks together.
Switches tasks
Sends data between computers on a Local Area Network. They segment traffic by forwarding traffic to the correct location.
NIC (Network Interface Controller/Card) tasks
Connects a device to a wired or wireless networking connection and uses a protocol to ensure successful communication.
Transmission media
Carry data signals from one computer to another.
DNS (Domain Name Server)’s role
A Domain Name Service is made up of multiple Domain Name Servers. Role in the conversion of a URL to an IP address.
Define hosting
The storing of files and data on a web server. The web server is referred to as a host.
The Cloud’s role
The cloud is servers that are used to store data and programs and can be accessed over The Internet.
Webservers and Client’s role
Host websites and deal with client requests.
3 star and mesh network topologies
Star network topology, full mesh network topology, partial mesh network topology
Explain star network toplogy
All the devices connect into a central switch. The switch is intelligent and makes sure traffic only goes where it is intended.
Explain full mesh network topology
Every device is connected to every device. The advantage is if you get a break in any of the connections you can still route your traffic via another route.
Explain partial mesh network topology
In this network topology multiple routes exist between different devices. However, every device is not connected to every single other device - compromised solution.
2 modes of connection
Wired - ethernet, wireless - bluetooth / Wi-Fi
3 advantages of Wi-Fi
Move around freely, easier to set-up, less expensive than wired
4 disadvantages of Wi-Fi
Speeds are slower than wired, relied on signal strength to the WAP, signal can be obstructed, less secure than wired
What is the range, amount of bandwith / power that Wi-Fi takes?
Range of about 100m, high bandwidth, takes quite a lot of power
What is the range, amount of bandwith / power that bluetooth takes?
Range of about 10m, low bandwidth, takes very little power
Define encryption
The process of scrambling data so that it cannot be read without a translation key. Unencrypted messages are referred to as plaintext.
Encrypted messages are referred to as ciphertext.
Function of IP (Internet Protocol) addressing
Used to route frames on a WAN (packets). Every device on the Internet has a unique IP which is assigned by a server.
Function of MAC (Media Access Control) addressing
A unique serial number assigned to each network interface controller (NIC). It is used to route frames on a LAN.
Define standard
A set of specifications for hardware/software. Enables products to be compatible with each other and interact with each other.
Examples of standards
ASCII/Unicode, IEEE, HTML, PNG/GIF/MP3
6 common protocols
TCP/IP, HTTP(S), FTP, POP, IMAP, SMTP
Function of TCP/IP (Transmission Control Protocol/Internet Protocol)
Used to communicate over LANs and WANs.
Function of HTTP(S) (Hypertext Transfer Protocol (Secure))
Used for webpage requests.
Function of FTP (File Transfer Protocol)
Used for file transfers.
Function of POP (Post Office Protocol)
Used for receiving email. Downloads email from the server to your device and deletes it from the server.
Function of IMAP (Internet Message Access Protocol)
Used for receiving email. Keeps email on the server. Allows your device to stay in sync with the server.
Function of SMTP (Simple Mail Transfer Protocol)
Transfers outgoing emails from one server to another / from an email client to a server.
What is the concept of layers
To divide the complex task of networking into smaller, simpler tasks that work with each other. The hardware / software of each layer has a defined responsibility. Each layer provides a service to the layer above it.
