The Internet & How it Works

• What is the structure of the Internet?

  A global network of interconnected networks
• What role do packet switching and routers play in the Internet?

  They facilitate data transfer across networks
• What is a router?

  A device that forwards packets to destinations
• What is a gateway?

  A device that forwards packets between protocols
• Where are routers used in the Internet?

  To forward packets to correct destinations
• How is routing achieved across the Internet?

  By determining the best outgoing link for packets
• What does URL stand for?

  Uniform Resource Locator
• What is a Fully Qualified Domain Name (FQDN)?

  It includes both host and domain name
• What is the purpose of a Domain Name Server (DNS)?

  To translate FQDN into IP addresses
• How are domain names organized?

  By hierarchies with unique registrations
• What is an IP address?

  A number identifying devices on a network
• What is the format of an original IP address?

  32 bit / 4 byte code like 123.456.78.123
• How do domain names function as proxies for IP addresses?

  They translate names into IP addresses via DNS
• What are the main components of a packet?

  • Payload: the actual message
  • Header: includes sender, recipient, packet number, and total packets
• What is the process of packet switching?

  • Data is transferred as packets
  • Different packets may take different routes
  • Endpoints check for complete data receipt
• What are the features of a home hub provided by an ISP?

  • Ethernet switch for wired devices
  • Wireless Access Point (WAP) for wireless connections
  • Router for managing outgoing connections
  • Modem for signal conversion
• What is the role of a router in a packet-switched network?

  • Examines destination address of packets
  • Uses routing table to decide next hop
  • Buffers packets to manage high latency
• What are the types of Top Level Domains (TLDs)?

  • .com: commercial/business
  • .gov: government
  • .org: non-commercial organizations
  • .net: internet services
  • Country codes: e.g., .uk, .es
• What happens if a DNS cannot solve a query?

  • The query is passed to another DNS server
  • Supports local distribution by returning one IP address
• What is the significance of the Time to Live (TTL) counter in packets?

  • Prevents packets from looping indefinitely
  • Discards packets when TTL reaches 0
• What is the purpose of Internet registries?

  • To manage domain name registrations
  • Ensure uniqueness of domain names
• What is the function of the Type of Service (ToS) field in IP packets?

  • Marks packets with priority levels
  • Routers may choose to abide by these levels
• What is the difference between a router and a gateway?

  • Router: forwards packets within the same protocol
  • Gateway: forwards packets between different protocols
• What is the significance of connectionless communication in the Internet?

  • Endpoints are responsible for data receipt
  • Most traffic uses packet switching
• What is the role of an ISP in connecting to the Internet?

  • Sells internet access to clients
  • Provides access to the internet backbone
• What is the function of the payload in a packet?

  • Contains the actual message being sent
• What is the function of the header in a packet?

  • Includes sender and recipient information
  • Contains packet number and total packets
• What is the significance of buffering in routers?

  • Manages high latency by storing packets temporarily
  • Allows for smoother data transmission
• What is the function of the modem in a home network?

  • Converts signals for outgoing media
• What is the role of the WAP in a home hub?

  • Provides wireless connections for devices
• What is the purpose of the ethernet switch in a home hub?

  • Connects wired devices to the network
• What is the role of the payload in a packet?

  • Contains the actual message being sent
• What is the significance of the header in a packet?

  • Includes sender and recipient information
  • Contains packet number and total packets
• What is the significance of buffering in routers?

  • Manages high latency by storing packets temporarily
  • Allows for smoother data transmission
• What happens if a packet is sent to an unreadable address?

  • It may be rerouted to a default device
  • Can cause a loop in packet transmission
• What is the relationship between domain names and IP addresses?

  • Domain names are proxies for IP addresses
  • DNS translates domain names into IP addresses
• What is the purpose of the ICANN in domain name registration?

  • Ensures uniqueness of domain names
  • Manages the central registry of domain names
• What is the significance of the hierarchy in DNS servers?

  • Not all DNS servers have the same information
  • Allows for efficient query resolution
• What is the role of the Internet backbone?

  • Provides the main pathways for data transmission
  • Connects various ISPs and networks
• What is the function of the modem in a home network?

  • Converts signals for outgoing media