3.1 Networks Flashcards
Network
Set of computer or computer systems that are interconnected and share resources and data
Node
A device in a network
Client
A computer or a software application that requests a service from a server connected in the same network
Hub
Connection Point for all nodes on a single network connected via ethernet cables
DATA TRANSFER
Device–> Hub –> Device
Switch
Connection point but can identify which device is connected to which port. It will only send it to the target devices
Whereas Hub sends data to all devices
Router
Device that connects network to another network
LAN
Local Area Network
Networks connected within limited geographical are
(eg. home, school, office, etc.)
VLAN
Virtual Local Area Network
Devices from different segments in a LAN connected logically
(eg. LAN in a hospital with different departments)
WLAN
Wireless Local Area Network
Connects nodes in a limited geographical but without any wires
Less Secure than LAN
WAN
Wide Area Network
Connects computer systems or LANs from different geographical areas
(eg. internet)
SAN
Storage Area Network
Type of LAN designed specifically to handle large data transfers.
PAN
Personal Area Network
Network that covers individual’s working area, extremely small
(eg. iPhone and AirPods)
P2P
Peer to Peer Network
Uses a distributed networl architechture where all systems in teh network are all decentralized.
All nodes are clients and servers at the same time.
Standards
A set of guidelines and minimum requirements which must be matched by all networks. If they are not kept,
–>incompatability issues will arise
(eg. PCI Standard
Standard for a slot on motherboard and expansion cards. All cards that follow the PCI standard will be able to fit and communicate with the motherboard)
3.1.3 Describe how communication over networks is broken down into different layers
–>Organising the network into layers makes the process less complex.
–>Each problem is spilt into distinct modules.
–>Each Layer carries out a sequence of operations
OSI Model
Physical
Data Link
Network
Transport
Session
Presentation
Application
“Please Do Not Take Steve’s Pet Alligator”
TCP/IP model
describes all the functions that take place at each layer of protocols within the TCP/IP suite
–> Represents all the functionailty required for succesful communication between users.
Network
Internet
Transport
Application
“NITA” ambani
See Docs for Image
VPN
Virtual Private Network
Makes a tunneled network connection through the Internet or any other public network
–> Ideal for secure connections
–>Allows clients from distant locations to connect for reasons such as LAN not having cables long enough or WAN too far for secure connection.
Hardware/ Software Requirements of VPN
- Internet Access (S)
- VPN software (S)
- VPN router (H)
- VPN applicance (H)
- VPN concentators (in order to handle large groups) - (S)
- VPN servers (S)
Secure VPN
All traffic is encrypted/ authenticated and sent along virtual tunnels
Trusted VPN
All traffic relies on the security of a provider’s network to protect the network.
Hybrid VPN
Combination of Trusted and Secure VPN.
Site-to-Site VPN
Connects entire network and facilities secure data inchange between different sites.
–> Gateways are always used
Check textbook for image
p.147
Remote-Accesss VPN
Connects Individual hosts to private networks and faciliites teleworkers who need access to their company’s network securely using the internet.
–> Host must have VPN client software installed.
3.1.5 Evaluate the use of a VPN.
–> Communication is easier
–> Offers flexibility to remote workers
–> Improves security
–> Improves overall productivity
Protocol
International rules that ensure the transfer of data between systems.
Strited Fixed Predefine
eg. TCP/IP
Data Packet
Portion of a message that is transmitted through a network.
Contains data such as:
–> input
–> transmissions
–>storage or processing
Data Integrity
The accuracy of data after input, tranmission, storage or processing
Source Integrity
The identity of the sender has been validated.
Can be proven with Digital Signature.
Flow Control
The process of directing the flow of execution of a program, allowing different parts of the program to be executed depending on certain conditions.
Determines the order of instructions to be executed
Congestion Management
When the request on the network resources exceeds the offered capacity
Error Correction
The ability to repair the error
Error Checking
The process to determine the error
Bandwidth
The theoretical speed of data in a medium
Throughput
The actual transfer rate of data in a medium
Bottleneck
In a network with many segments, the slowest segment creates a bottleneck that affects the throughput of the network
Goodput
Measures the transfer rate of usable data
Factors that affect the speed of data transmission
- Bandwidth of the network
- Data Transfer rate of storage devices
- Interferences
- Type of file
- CPU Speed
- Number of connected devices
Data Compression
Reduces the size of files to be transmitted over a network
Lossy Data Compression
A compression method that loses some information, No way to get the original file back
(eg. JPEG, MPEG2, MP3)
Lossless Data Compression
This method reduces the number of bits by identifying and then eliminating any statistical redundancy. No loss of any data.
(eg. GIF)
Wired Communication (5 kinds)
Copper Cable –> Common kind of cabling in computer networks
Coaxial Cable –> 2 copper conductors, low installation costs
Unshielded Twisted Pair Cable (UTP) –> Popular in LANs, easy to install, prone to electrical interference, Low installation costs
Shielded Twisted Pair Cable –> More difficult to instal that UTP.
Fiber Optic Cable –> Carries beam of Light, Expensive, offers higher speeds, Extremely secure
Wireless Communication
- Microwave Radio
- Infrared
- RFID
- Bluetooth
- Free Space Optics
Microwave Radio
Microwave Radio –> used extensively for mobile telephone networks and LANs. Information is carried through air.
Offers high bandwidth
Difficult to guarantee reliability
Weather can affect performance
eg. Satellites
Infrared
Used only for short distances. Advanced Security. Cannot pass through objects
RFID
Uses various radio technologies, needs internal power. No need for internal power source
Bluetooth
Uses microwave radio to exchange radio. They transmit at very low power levels. Frequencies change regularly
Free Space Optics
Use of lasers for wireless computer communication
Characteristics of the different transmission
Check Textbook - p154
Data Packet
Unit of information in a form suitable to travel between computers
Packet Switching Communication Method
Refers to a communication method used in computer networks in which data are grouped in packets.
The original file is divided into packet before transmission and each packet may follow a different path to the destination
Datagram Packet Switching
Each packet contains the receiver’s address
The path each packet takes can be different
