Network Protocols & Communication

• Data communication


  The exchange of data between two nodes
• Data flow types


  • Simplex
  • Half-duplex
  • Full-duplex
• Simplex communication


  Unidirectional communication where one node can transmit and the other can only receive. (Example: Keyboard)
• Half-duplex communication


  Communication can happen in both directions but not at the same time. If one device is sending, the other can only receive, and vice versa. (Walkie-Talkies)
• Full-duplex communication


  Communication can happen in both directions simultaneously where the device can send and receive at the same time. (Example: Telephone line)
• Protocol


  A set of rules that governs data communication
• Elements of protocols

  • Message encoding
  • Message formatting and encapsulation
  • Message timing
  • Message size
  • Message delivery options
• Message encoding


  The process of converting data into signals or waves for transmission over the communication medium
• Message formatting and encapsulation


  Sender and receiver must agree on a common format, and data is encapsulated with source and destination information
• Message timing


  Deals with flow control and response time, ensuring the sender does not overwhelm the receiver
• Message size


  The protocol must ensure the message size is appropriate for the communication medium
• Message delivery options


  • Unicast (one-to-one) (One sender sends data to only one receiver)
  • Multicast (one-to-many) (One sender sends data to one set of receivers)
  • Broadcast (one-to-all) (One sender sends data to all receivers)
• Protocols are important in both computer networks and human communication