1.3.3 Network

• What is the definition of a network?

  Two or more computers connected to transmit data
• What are the two main types of networks?

  Local area networks and wide area networks
• What is a local area network (LAN)?

  A network spread over a small geographical area
• What is a wide area network (WAN)?

  A network spread over a large geographical area
• Why do large corporations use WANs?

  To communicate between different office locations
• What is a protocol in networking?

  A set of rules for computer communication
• Why are protocols standardized?

  To ensure devices communicate regardless of manufacturer
• What does HTTP stand for?

  Hypertext Transfer Protocol
• What is the purpose of HTTPS?

  To provide a secure version of HTTP
• What does TCP/IP stand for?

  Transmission Control Protocol / Internet Protocol
• What is the function of TCP/IP?

  Routing packets through networks
• What are POP3 and IMAP used for?

  Email access protocols
• What does FTP stand for?

  File Transfer Protocol
• What is the Internet described as?

  A network of networks
• How are continents connected in the Internet?

  Using large international backbone cables
• What is the TCP/IP stack?

  A stack of networking protocols
• What are the layers of the TCP/IP stack?

  • Application Layer
  • Transport Layer
  • Network Layer
  • Link Layer
• What does the application layer specify?

  What protocol to use for the application
• What is the role of the transport layer?

  Establishing end-to-end connections and packet management
• What does the network layer add to packets?

  Source and destination IP addresses
• What is a socket address?

  Combination of IP address and port number
• What does the link layer add to packets?

  MAC addresses of source and destination
• What happens to the MAC address on the recipient's computer?

  It is removed by the link layer
• What is the difference between LAN and WAN?

  LAN is small area; WAN is large area
• What is the role of the DNS?

  To name and organize internet resources
• What does TLD stand for?

  Top Level Domain
• Why are domain names used instead of IP addresses?

  They are easier to remember
• What does a DNS server do?

  Translates domain names into IP addresses
• What are data packets?

  Segments of data containing various information
• What information does the header of a packet contain?

  Sender and recipient IP addresses, protocol, order
• What is the purpose of Time To Live (TTL) in packets?

  To tell the packet when to expire
• What does the trailer of a packet contain?

  Checksum or cyclic redundancy check
• What is packet switching?

  Data communicated using packets across a network
• What are the advantages and disadvantages of packet switching?

  Advantages:

  • Multiple methods ensure data integrity
  • Multiple routes can be used
  • Can transfer packets over large networks

  
  

  Disadvantages:

  • Time spent deconstructing packets
  • Must wait for all packets to arrive
• What are the advantages and disadvantages of circuit switching?

  Advantages:

  • Data arrives in logical order
  • Enables calls without delay

  
  

  Disadvantages:

  • Wasted bandwidth during idle times
  • Ties up network sections until transmission completes
• What is the purpose of a firewall?

  To prevent unauthorized access to a network
• What are packet filters?

  Preconfigured rules for network access
• What is circuit switching?

  A direct link created between two devices
• What happens when access is denied by a firewall?

  Packet can be dropped or rejected
• What is the role of a proxy server?

  Acts as an intermediary for data