3.1 Networks Flashcards by nihar morakhia

Network

Set of computer or computer systems that are interconnected and share resources and data

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Node

A device in a network

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Client

A computer or a software application that requests a service from a server connected in the same network

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Hub

Connection Point for all nodes on a single network connected via ethernet cables

DATA TRANSFER
Device–> Hub –> Device

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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

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Router

Device that connects network to another network

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LAN

Local Area Network

Networks connected within limited geographical are

(eg. home, school, office, etc.)

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VLAN

Virtual Local Area Network

Devices from different segments in a LAN connected logically

(eg. LAN in a hospital with different departments)

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WLAN

Wireless Local Area Network

Connects nodes in a limited geographical but without any wires

Less Secure than LAN

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WAN

Wide Area Network

Connects computer systems or LANs from different geographical areas

(eg. internet)

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SAN

Storage Area Network

Type of LAN designed specifically to handle large data transfers.

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PAN

Personal Area Network

Network that covers individual’s working area, extremely small

(eg. iPhone and AirPods)

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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.

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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)

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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

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OSI Model

Physical
Data Link
Network
Transport
Session
Presentation
Application

“Please Do Not Take Steve’s Pet Alligator”

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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

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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.

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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)

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Secure VPN

All traffic is encrypted/ authenticated and sent along virtual tunnels

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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

1. Bandwidth of the network 2. Data Transfer rate of storage devices 3. Interferences 4. Type of file 5. CPU Speed 6. 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

1. Microwave Radio 2. Infrared 3. RFID 4. Bluetooth 5. 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