#Computer-Networks

Internet

Since the explosive growth of web-based applications, every developer stands to benefit from understanding how the Internet works. Through this article and its accompanying introductory series of short videos about the Internet from code.org, you will learn the basics of the Internet and how it works. After going through this article, you will be able to answer the following questions:

# Topic covered
* Computer Network
* Types of computer networks
  * PAN, LAN, CAN, MAN, WAN
* Types of Transmission Media
  * Guided Media
  * Unguided Media
* Transmission Modes in Computer Networks
  * Simplex, Half-Duplex, Full-Duplex
* Types of Network Topology
  * P2P, Bus, Ring, Star, Tree, Mesh, Hybrid
* Data Transmission
  * Unicast, Broadcast, Multicast

# Topic covered
* OSI Model
  * Physical, Data-link Layer
  * Network Layer
  * Transport Layer
  * Session, Presentation, Application Layer
* TCP/IP model

# Topic covered
* Network Devices
  * Repeater, Hub, Bridges, Switch, Router Modem
* Client, Server, Host, Noise, Distortion
* Who governs the Internet?
* Internet, Intranet and Extranet

# Topic covered
* Transmission Control Protocol (TCP)
  * TCP Three-Way Handshake Process
* User Datagram Protocol (UDP)
* TCP vs UDP
* When to use UDP and TCP?

# Topic covered
* Hypertext Transfer Protocol (HTTP)
* What’s in an HTTP request?
* What’s in an HTTP response?
* Generation of HTTP(HTTP version type)
  * HTTP/1.0
  * HTTP/2
  * HTTP/3 (QUIC)

# Topic covered
* What is DNS?
* DNS Servers
  * DNS resolver, Root, TLD and  Authoritative
* Who operates DNS root servers?
* How do resolvers find DNS root servers?
* Types of DNS queries
  * Iterative
  * Recursive
* How does the Domain Name System (DNS) lookup work?
* Why does DNS use UDP and not TCP?

# Topic covered
* SSL/TLS encryption protocol
* SSL Certificates
    * What is https and how to install SSL certificate
* What is HTTPS?
* How does HTTPS (SSL/TLS) work?
* Why does HTTPS switch to symmetric encryption during data transmission?

# Topic covered
* Mail Protocol
  * Simple Mail Transfer Protocol
  * POP3 vs IMAP
  * SMTP & POP & IMAP
* WebSocket