TCP , IP , DNS & Protocol layers

• How is the internet different from the World Wide Web?

  The internet is a network of networks, while the World Wide Web is a service that runs on the internet
• What components make up a home network connected to the internet?

  • Wireless router
  • Internet Service Provider (ISP)
  • Domain Name Server (DNS)
  • Other routers
• What is the role of the router in a home network?

  To connect the home network to the Internet Service Provider
• What is the backbone of the internet composed of?

  Routers, cables, satellites, and other hardware
• What is the complexity involved in networking computers together?

  It involves various factors that must be considered for successful communication
• What are protocols in networking?

  Standards that allow two devices to communicate
• What is the purpose of protocol layering in networking?

  • To divide complex networking tasks into simpler tasks
  • Each layer has a defined responsibility
  • Layers work in tandem to provide services to each other
• What is TCP/IP?

  One of the most important protocol stacks in use today
• How many layers does the original TCP/IP model have?

  Four layers
• What is the updated TCP/IP model's layer structure?

  It has five layers, splitting the link layer into data link and physical
• What is the top layer of the TCP protocol model called?

  The application layer
• What protocols are included in the application layer?

  • FTP (File Transfer Protocol)
  • HTTP (Hypertext Transfer Protocol)
  • SMTP (Simple Mail Transfer Protocol)
• What is the function of the transport layer in the TCP/IP model?

  It sets up communication between two hosts and agrees on settings
• What protocols are found in the transport layer?

  TCP (Transmission Control Protocol) and UDP (User Datagram Protocol)
• What is the role of the internet layer?

  It addresses packets for data transmission and routes them across the network
• What does the link layer do in the TCP/IP model?

  It facilitates the transmission of binary data via any media
• What happens when a message is sent through the TCP/IP stack?


  1. Application layer adds a header and creates a segment
  2. Transport layer establishes connection and splits data into packets
  3. Internet layer adds source and destination IP addresses
  4. Link layer adds MAC addresses and creates frames
• What is a segment in the context of TCP/IP?

  A message combined with a header added by the application layer
• What is the purpose of numbering packets in the transport layer?

  To ensure they can be reassembled in the correct order at the destination
• What is a socket in networking?

  The combination of an IP address and a port number
• What does the link layer add to packets?

  The unique media access control (MAC) address
• Why do we need both MAC addresses and IP addresses?

  • MAC addresses are used for communication within a local area network (LAN)
  • IP addresses are used for routing traffic over wide area networks (WAN)
  • MAC addresses identify devices, while IP addresses indicate their location
• How does the ARP protocol function in networking?

  It helps find the destination MAC address when the router doesn't already know it
• What happens to MAC addresses as packets travel through routers?

  • The source and destination MAC addresses are overwritten at each hop
  • The original MAC address is replaced by the router's MAC address
• What is the process of sending a message from one host to another on the same network?

  One host can send directly to the other using the MAC address
• How do switches learn MAC addresses in a local area network?

  By examining the source and destination MAC addresses of traffic passing through
• What happens when data is transmitted over the internet?

  The data is sent via routers, with the destination MAC address being that of the router
• What is the role of the router when it receives a frame?

  It determines where to send the packet by looking at the destination IP address
• What is the process of data encapsulation in TCP/IP?

  1. Original message is split into segments
  2. Segments are wrapped into packets
  3. Packets are wrapped into frames
• What happens to frames when they reach their final destination?

  They travel up through the layers of the TCP stack, stripping off headers and tails
• What is the World Wide Web?

  • A collection of files and information stored in hypertext
  • Composed of web pages and associated files hosted on web servers
• What does a web server do?

  It stores files and handles client requests for web pages or resources
• What is the role of the Domain Name System (DNS)?

  To map domain names to IP addresses
• What is the process when a user requests a URL in a browser?

  1. The browser sends the domain name to the DNS
  2. DNS maps the domain name to an IP address
  3. The IP address is used to send a request to the web server
  4. The web server returns the requested resource to the browser
• What happens when a browser queries a DNS resolver server?

  The server queries a DNS root name server for the address of the top-level domain server
• What does the DNS resolver do after receiving the address from the root server?

  It makes requests to the top-level domain server
• What is the final step in the DNS resolution process?

  The DNS resolver responds to the web browser with the IP address