Video 1

at first computers were big and only worked in isolation

  • however, as time went on, computers became smaller and smaller
  • computing devices like routers were also invented
  • however computers were still working alone

  • the users of computers needed them to be able to communicate with other devices

  • computers communicate with binary, which is combines into “packets”
  • computer networks were created for computers to be able to send packets to each other
  • a computer network is a group of interconnected computers that send data to each other

Packet Switching:

  • a file/message is sent by being broken up into packets along a path
  • the packages can be sent in any order, since they are rearranged back into order by the receiving computer
  • routers are used to “guide” packages to their destination by finding the correct path

Bandwidth: the max amount of data that can be sent within a certain period of time on a computer network (speed)

  • usually measured in bits per second
  • the more information there is on a network, the slower it becomes

Why do computers need to communicate?

  • communicating/sharing data makes a lot of tasks easier

Why are packets used to transmit data?

  • an entire file can’t be moved across the internet in one go
  • packets are used to send the file in separate pieces

Vocab:

  • path: sequence of connected computers/computing devices. The path starts at the sender and ends at the receiver
  • route: the process of finding a path for the packets to reach the receiver
  • computer system: a group of computing devices working together to achieve a goal
  • computer device: a device that can run a program (like computers, tablets, servers, routers, etc)
  • bandwidth: the maximum amount of data a computer can send at a time
  • computer network: interconnected computing devices that can send and receive data from each other

Video 2:

  • protocol: an agreed-upon set of rules that spell out the behavior of a system
  • Internet Engineering Task Force: discussed the protocols/rules to send info from one computer device to another

Network access layer:

  • deals w/ hardware
  • starts w/ something like wifi card
  • has a MAC address

Internet Protocol Layer (narrow waist):

  • package is set up w/ metadata – has sender IP and receiver IP
  • goes through a path of router
  • like passing a note through a class
  • there are multiple paths that the package can take – internet is flexible and scalable (it is able to change in size to meet new demands)

Transport Layer:

  • Two most popular protocols: TCP and UDP
  • TCP is stricter (makes sure the package has been delivered): uses “three way handshake” to certify delivery
  • UDP is more relaxed

Application Layer:

  • DNS: Domain Name Service – translates numbers into a URL readable by humans which directs you to an IP address
  • WWW: World Wide Web: network of linked data pages over the Internet (NOT the internet itself)
  • http/https: asking to receive data from web servers (https is a more secure version of http)