• Computers went from big to small
  • People wanted a way for computers to communicate between different systems
  • The computers need to send and receive the data
  • Computer system: a group of computers which work together for a joint purpose
  • Computer network: a group of interconnected computing devices capable of sending or receiving the data
  • Packet switching: the file is broken up into packets and are sent in any order. The packets are reassembled in the correct order.
  • Routing: the process of finding a path from sender to receiver
  • Path on a computing network: between device sending and receiving information, directly connecting the start(sender) to the end(receiver)

  • Bandwith: maximum amount of data which can be sent during a fixed time, measured in bits per second

  • Protocol: agreed upon set of rules that specify the behavior of systems
  • Internet Engineering Task Force: Manages the development of standards and technical discussions concerning the internet in an open and collaborative process
  • Transmission Control Panel(TCP): Establishes a common standard for how to send messages between devices on the internet

  • Open Systems Interconnect(OCI): The layers you have to go through to communicate

  • Network Access Layer: usually has to do with hardware, how the computers use transport
  • Examples include: Datalink, Fiber, Ethernet, Wire,

  • Each card has a MAC address, which is unique to each card. Computers use this to send information

  • Internet Data Transmission
  • Each packet has the data being transported, as well as metadata
  • Metadata is the data which contains information for routing information from sender to receiver
  • Routers are special purpose computers with a MAC address
  • Computers send data, to a router, which will either deliver to final location, or another router which will put on a path to the proper location
  • Internet was designed to be able to change in size and scale to meet new demands
  • Local Area Network(LAN): physical connections of computers in a close location, 1 - 100s systems
  • Intranet: LANs connected by routers in a system, 100s - 1000s systems, usually in an organization
  • Autonomous Systems: Larger intranets linked together under the control and policies of major organizations. Large routers link networks with large telecommunications connections, 10s of 1000s of systems. Controlled by internet providers
  • The Internet: Autonomous Systems linked together, large routers linking ass via Special Telecomm Means(Fiber, T3 Satellites), Major Infrastructure( DNS, Cyber Operations)

Transport

  • TCP: makes sure that receiver has gotten the package, slow but reliable
  • UDP: does its best effort to get the package, fast but not guaranteed
  • Port: number assigned to application or service 3 targets as defined by IP
  • Unicast: a specific device. Internet wide access, TCP is used
  • Multicast: a group of devices. Specific range of IP addresses, Internet wide access, UDP is used
  • Broadcast: all devices. LAN wide, data stops at router, UDP is used

Application

  • Domain Name Service: database which gives names to IPS. There are large servers which manage the name/IP mappings for each domain(.com, .net, .gov)

  • Web Servers: programs running on machines connected to the Internet

  • The World Wide Web, WWW, is a network of linked data and programs running over the Internet
  • http. : how to ask and receive data from servers, usually uses TCP, with Port 80 has the transport layer
  • https. : like http., but has security, usually uses TCP Port 443