Networking Concepts and Internet Protocols

Networks

  • Definition of Networks

    • The Internet is categorized as a network.

    • Networks consist of a physical system including:

    • Wires

    • Cables

    • Servers

    • Routers

    • Connected devices

  • Clarification of Concepts

    • The World Wide Web is NOT a network; it represents content available on the network, such as:

    • Files

    • Web Pages

    • Media

  • Performance Characteristics

    • Direct connections are recognized as fastest but typically come with higher costs.

    • Networks should be designed to be fault-tolerant and include built-in redundancy.

Lesson 1: Internet - Layers of Abstraction

  • Demonstration of Message Transmission

    • User Interaction:

    • An example of a message from user "Hannah" featuring an ASCII test.

    • Message Breakdown:

    • ASCII representation of the word "Test":

      • Decimal: 084 101 115 116

      • Binary: 01010100 01100101 01110011 01110100

    • Message from Hannah stating "Hello":

      • ASCII: Hello

      • Decimal: 872 101 108 108 111

      • Binary: 01001000 01100101 01101100 01101100 01101111

Computing Devices and Systems

  • Computing Device

    • Definition: A device capable of running software, encompassing:

    • Computers

    • Tablets

    • Servers

    • Routers

    • Smart sensors

  • Computing System

    • Definition: A collective of computing devices and programs collaborating for a unified purpose.

  • Computing Network

    • Definition: An interconnected set of computing devices that can send or receive data.

  • Data Transmission Path

    • Definition: The sequence of connections between computing devices on a network, starting from the sender and concluding at the receiver.

  • Bandwidth

    • Definition: The maximum quantity of data that can be transmitted in a specified time frame, generally measured in bits per second.

Internet Protocol (IP)

  • Overview

    • The Internet is characterized as a distributed, packet-switched network with no central command.

  • Protocol Governance

    • Core design philosophy and architecture governed by protocols:

    • Who is in charge of the Internet? - The answer is “Everyone and no one!”

    • IETF: Internet Engineering Taskforce formulates these protocols.

  • Definition of Protocols

    • Explanation: A well-established set of rules and standards for machine communication.

    • Agreement on protocol usage is crucial for seamless communication across devices.

  • IP Addresses

    • Assignment of unique addresses to all Internet-connected devices:

    • IPv4:

      • Composition: 32-bit addresses.

      • Example: 174.129.14.120 for human readers and 10101100.10000001.00001110.01111000 for machines.

      • Capacity: Approximately 4 billion unique IPv4 addresses available.

    • IPv6:

      • Composition: 128-bit addresses.

      • Capacity: Up to 340 undecillion possible addresses.

Unit 2 Lesson 3 Wrap Up

  • Protocol

    • Description: An agreed-upon set of rules dictating the behavior of a system (similar to military protocol).

  • IP Address

    • Definition: The unique numerical label designated to each device on the Internet.

  • Internet Protocol (IP)

    • Description: The protocol governing data transmission across the Internet, allocating unique IP addresses to each connected device.

Routers and Redundancy

  • Router Functionality

    • Definition: A computer type responsible for forwarding data across a network.

  • Redundancy Importance

    • Multiple paths exist between locations on the Internet, contributing to:

    • Efficiency: Alters routes based on current traffic conditions to enhance speed.

    • Reliability: Multiple paths ensure continuity if one fails.

  • Visibility of Routed Messages

    • Routed messages may not be visible to all users but can still be observed by router owners.

Unit 2 Lesson 4 Wrap Up

  • Redundancy

    • Definition: The inclusion of additional components to maintain system operation despite component failures, e.g., multiple paths enabling connectivity.

  • Fault Tolerance

    • Definition: The capacity to continue functioning despite individual component failures.

    • Importance: Essential for the stability of complex systems like computer networks where unexpected failures can occur.

Transmission Control Protocol (TCP) and Packets

  • Message Transmission

    • Overview: Messages sent over the Internet are divided into smaller packets, each routed individually.

    • Example: Every website view.

  • Confirmation System

    • The receiving computer confirms packet receipt.

    • If a sending computer does not receive confirmation, the packet is resent.

  • Packet Characteristics

    • Packets can arrive out of order; metadata included indicates correct ordering.

    • Different routes may be taken by packets.

Unit 2 Lesson 5 Wrap Up

  • Role of IP Addresses

    • Sender and receiver IP addresses facilitate message routing.

  • Datastream

    • Definition: Information transmitted via the Internet in packet form.

  • Packet Definition

    • Description: A unit of data transferred over a network; larger messages are segmented into packets.

    • Delivery Conditions:

    • Packets may arrive in sequence, out of sequence, or not at all.

  • Packet Metadata

    • Definition: Annotations added to packets to guide routing and message reassembly.

TCP Protocols

  • Transmission Control Protocol (TCP)

    • Protocol facilitating packet transmission with error checking.

    • Ensures all packets are received and correctly ordered.

  • User Datagram Protocol (UDP)

    • A faster protocol for sending packets with minimal error-checking, lacking resends for any lost packets.

Domain Name System (DNS)

  • Purpose of DNS

    • Definition: Associates website names with their corresponding IP addresses.

    • Example: Converting "code.org" to 174.129.14.120.

  • Internet Communication Framework

    • The Internet operates as a network of computers exchanging messages to request and provide information.

  • Identification in Communication

    • Essential for computers to identify "from" and "to" in every message, communicated through numerical IP addresses.

    • Necessity of translating human-readable names (URLs) into IP addresses.

  • Hierarchical Server System

    • DNS operates in a non-centralized manner, engaging a collaborative hierarchical system for maintenance of authoritative address tables.

    • The system's proper functionality depends on collaborative efforts among users for accuracy and currency.

HyperText Transfer Protocol (HTTP)

  • Definition of HTTP

    • Characterization: A high-level protocol defining communication between Internet users (clients) and data servers.

    • Main Uses: Sending and receiving web pages, images, videos, audio, and files.

  • Client-Server Interaction

    • A client transmits a request to the server, prompting the server to respond with the requested data.

Unit 2 Lesson 6 Wrap Up

  • Distinction between Internet and World Wide Web

    • The World Wide Web consists of files, web pages, and multimedia, whereas the Internet is the infrastructure facilitating access to that content.

  • Importance of DNS

    • Role: Critical for the scalability and functionality of the Internet.

  • Definitions

    • Scalability: The ability of a system to adapt in size and capacity to meet evolving demands.

    • Domain Name System (DNS): The mechanism for converting domain names (e.g., example.com) into IP addresses.

    • World Wide Web: An interconnected framework of linked pages, programs, and files.

    • Hypertext Transfer Protocol (HTTP): The standard protocol for requesting and sharing web content over the Internet.

Internet Protocols Overview

  • DNS Request Process

    • DNS translates a URL into an IP address, conducted over TCP/IP.

  • Functionality of TCP

    • TCP divides larger messages into packets, ensuring receipt and proper order.

  • Role of IP

    • Assigns IP addresses and routes packets to the correct destination.

  • Structure of the Physical Internet

    • Components include copper wires, fiber optic cables, and radio waves.

Unit 2 Lesson 7 Wrap Up

  • Concept of the Digital Divide

    • Definition: Disparities in access to computing devices and the Internet due to socioeconomic, geographic, or demographic factors.

    • Impacts

    • Affects individuals and groups differently and raises ethical questions regarding equity, access, and influence at both local and global levels.

    • Influencing Factors

    • Determined by the actions of individuals, organizations, and governments, impacting who gains or lacks access.

    • Consequences

    • Individuals without Internet access face limited educational and informational opportunities, perpetuating cycles of poverty and wealth disparity.

    • Proposed Solutions

    • Advocacy for reclassification of Internet access as a utility to ensure regulated provision.