IB Computer Science Topic 3 - Networks

Definition

Term

Network Fundamentals

Nodes/Computers are connected to central node (computer or hub)

Nodes/Computers connected in a circle; no central node

"Bus" connects all devices through common cable

Computer system or software application that provides service to other computer systems on same network

Requests service from above connected to same network.

Connection point for devices on a single network that transfers data from one device to all other connected devices, slowing down network

Like above but knows which port to send data to

More sophisticated than above two, can join multiple networks and acts as intermediary between networks for effective and efficient data exchange between devices

Connects computer systems within small area such as house, office building, or school, allowing use of peripheral devices such as printers and external hard drives by connected computer systems.

Connects computer systems within large geographical area, such as cities, countries, or network of contries.

Allows large storage devices to be accessed by servers conveniently

Collection of private computer networks within company, school, or organization, whose main purpose is to facilitate communication between individuals or work groups and to improve data sharing.

Global network of a large array of computers and networks connected together

Utilizes above to selectively authorize users to specific LAN(s) or WAN(s); to everyone else, LAN or WAN in question is private.

Consists of websites and webpages, and support for services such as email and file transfer

Makes "tunnelled" network connection through Internet or any public network. Enables device to exchange and access data across Internet as if it were directly connected to a private network.

Interconnects devices centred around one person's workspace, maximum 10m range.

Uses distributed network architecture where all computer systems (nodes or peers) in network are decentralized and are clients and servers at the same time.

Provide common international "language" that enables compatibility for all computer systems globally

Most widely used example of above. Reference model that aims to facilitate communication across variety of systems.

Seven layers of above. First three mostly hardware, last four mostly software.

Data Transmission

International rules that ensure data transfer or communication between systems.

Portion of message that is transmitted through network. Has data such as check digits and destination address.

Accuracy of data following input, transmission, storage, or processing

Identity of sender has been validated. Can be proven by data signatures.

Slowing down data flow rate in order to prevent overload of resources due to limited memory and bandwidth in network infrastructures

When request on network resources exceeds capacity

When two or more network competing actions are waiting for other to finish but neither does

Process to determine error

Ability to repair error

Theoretical speed of data in media

Actual transfer rate of data. Affected by interference, traffic, number of connected devices, errors, etc.

Created by slowest segment of network that affects above

Transfer rate of usable data

Extra digit added to numerical data

Reduction of bits by encoding data using fewer bits than original file/representation

Some loss of information, no way to get original file back. Examples: JPG, MPEG2

Reduces number of bits by identifying and then eliminating statistical redundancy. No loss of information.

Most common cabling in networks

Cheap to install, consists of two copper conductors. Used in networks as well as carrying TV signals.

Two wires twisted with each other. Easy and cheap to install

Like above but pairs are wrapped. More difficult to install.

Carries beam of light, used for data transmission and telephone lines. Higher speeds with high security but very expensive.

Used extensively for mobile telephone networks and LANs. Information transmitted through air. High bandwidth but lower than cables.

Uses microwave signals

Only for very short distances, cannot pass through objects. Directional.

Operates with various radio technologies.

Uses microwave radio to exchange data at very low power levels. Frequencies change regularly.

Wireless computer communication with lasers

Communication method where file is divided into packets before transmission. Each packet is sent to destination via different routes. Delays are minimal.

Wireless Networking

(Hardware Components for Wireless Networks)

Allows wireless connection to Internet

Provided by wireless router, allows wireless data transfer between device and network.

Required for devices to connect to wireless network

Significantly increase effective communication area of wireless network. Fixed, optional, or removable.

Connects to router or access point

(end Hardware Components)

(Software Components for Wireless Networks)

Protocol that allows server to automatically assign IP address to client device. Very effective and convenient.

Network security system that determines what data comes in/goes out of network or computer

"Name" of WLAN. Maximum 32 characters, case-sensitive.

Handles system resources with responsibility for managing all protocols, hardware, and applications to cooperate so that network can function properly

Includes all software that prevents unauthorized access, use, disclosure, disruption, etc. Includes access, but not limited to, control, firewall, anti-spyware, anti-tamper, antivirus.

Specifies set of protocols for accessing information over mobile wireless network, e.g. Internet access, email exchange. Supported by most operating systems

Application software used to find, retrieve, and display content on WWW, including web pages, text, images, audio, videos, etc.

(end Software Components)

Third generation of mobile telecommunication technology. Mobile networking and telecommunications technology used in wireless telephony, GPS and location based services, mobile Internet access, video calls, and mobile TV. More secure than 2G.

Fourth generation of mobile telecommunication technology; released after above. Used for mobile Internet access to laptops, smartphones, etc.

Type of above, as well as standard for wireless communication of high-speed data for smartphones. Goal: to be fast and to have large capacity

Another type of above-above. Provides portable mobile broadband connectivity across cities or countries through many devices. Relatively low cost

Fifth generation of mobile telecommunication technology. Not yet publicly available but aims to be faster than previous generations.

Can measure data and parameters such as temperature, sound, and pressure for physical or environmental reasons such as sampling, security, health-care monitoring, and underware measurements.

Necessary to prevent unauthorized data access during Internet use. Uses complex mathematical algorithms and keys to render message incomprehensible to unauthorized people. Two categories below.

Same key for encryption and decryption

Public key for encryption and private key for decryption

Based on this, networks permit access to certain devices. Consists of 12 digits or letters e.g. 1a:2b:3c:4d:5e:6f; what every network card has when manufactured.

Most common data encryption technique, provides data confidentiality. Adds processing overheads that slow down wireless connection. Cracking is possible but novice users cannot do so. Offers interoperability with older devices/access to legacy wireless device.

Took over above as interim security measure. Uses Advanced Encryption Standard (AES) block cipher. Considered best protection but strong password still recommended

Network security protocol specially designed to allow novice and residential users to securely operate wireless network. Requires router and compatible devices. Has known security weaknesses.