Unit 2: The Internet

the Internet

world’s largest computer network, consisting of interconnected networks that use standardized, open communication protocols

protocol

rules that describe how computers can communicate with each other and behave in a system

• standardized: computers must agree about the way they communicate

• open: any computing device can join as long as they follow the rules

computer network

interconnected computing system that is capable of sending or receiving data

• EX) the Internet

computing system

a group of computing devices and programs that work together for a common purpose

• EX) a group of computers, WWW - World Wide Web

computing device

a physical object that can run a program

• EX) phone, tablet, computer

World Wide Web (WWW)

a system of webpages, programs, and files that runs on the Internet

• serves as a communication platform to exchange information across the internet 

Internet vs WWW

Internet: the global network infrastructure of interconnected computers

WWW: the service that uses this infrastructure

Internet Protocol (IP)

a protocol for sending data across the Internet that assigns unique numbers (IP addresses) to each connected device

IP Address

the unique number assigned to each device on the Internet

Transmission Control Protocol (TCP)

ensures reliable transmission of data from sender to receiver

• splits the data into small packets to be reassembled upon destination 

Domain Name System (DNS)

translates between a website’s domain name to and from its IP address

scalable

handles the increasing number of devices added to the Internet by adjusting its capacity

HyperText Transfer Protocol (HTTP)

the protocol used for transmitting web pages over the internet

packets

• units of data that are sent over a network

• splits large amounts of data into smaller units

TCP and packets

• allows multiple packets between computers

• checks that all packets arrive to its destination

• packets are tracked

• re-requests occur if a packet is missing

router

a type of computer that forwards data across a network

routing

finding a path from the sender to the receiver

path

series of connections between computing devices, with multiple paths, between a sender and a receiver

bandwidth

the maximum amount of data that can be sent in a fixed amount of time

• bits per second

• higher the bandwidth, the faster data arrives

latency

the time between sending/receiving a data message

• seconds (time)

• lower the latency, the less time data takes to transmit

redundancy

the inclusion of extra components so that the system can still operate even if individual components fail

fault tolerance

the ability for a system to work properly even if individual components fail

digital divide

refers to the gaps between those who have and do not have access to computing devices and the Internet