- Forward


Communication
An Introduction


Prof. David Bernstein
James Madison University

Computer Science Department
bernstdh@jmu.edu

Print

About the Word "Communication"
Back SMYC Forward
  • Etymology:
    • From the Latin communis meaning to share
  • Defined:
    • The transmission or exchange of information, knowledge, or ideas, by means of speech, writing, mechanical or electronic media, etc.;
Some Kinds of Communication
Back SMYC Forward
  • Oral
  • Written
  • Nonverbal
Models of Communication
Back SMYC Forward
  • Shannon and Weaver, 1949 (Bell Laboratories):
    • Information source produces a message
    • Transmitter encodes the message into signals
    • Channel carries the signals
    • Receiver decodes the message from the signal
    • Destination receives the message
  • Berlo, 1960:
    • Sender issues - skills, attitude, knowledge, culture
    • Message issues - content, elements, treatment, structure, codes
    • Channel issues - hearing, seeing, touching, tasting, feeling
    • Receiver issues - skills, attitude, kowledge, culture
The Focus of Computer Scientists and Engineers
Back SMYC Forward
  • "Hard" Technologies:
    • Transmission Equipment
    • Transmission Media
    • Sending/Receiving Devices
  • "Soft" Technologies:
    • Protocols
    • Algorithms
    • Software
Communication Networks
Back SMYC Forward
  • A Loose Definition:
    • A set of sources and destinations
    • A set of channels
  • Types of Communication Networks:
    • Human/Social
    • Physical
Physical Communication Networks
Back SMYC Forward
  • Some Obervations:
    • Every source-destination pair may not be directly connected
    • As a result, intermediaries may need to be involved
    • Hence, switching is required
  • Types of Switching:
    • Circuit Switching (i.e., reserved resources)
    • Packet Switching (i.e., resources on demand)
Properties/Issues to Consider
Back SMYC Forward
  • Delay/Timeliness
    • Processing Delay
    • Queueing Delay
    • Transmission Delay
    • Propagation Delay
    Expand
  • Capacity/Bandwidth
  • Reliability
  • Simplex, Half-Duplex, Full-Duplex
  • Asynchronous, Synchronous
    • Low-Level: Whether a timing signal is used
    • High-Level: Whether both/all parties are involved simultaneously
    Expand
  • Architecture
    • Client-Server
    • Peer-to-Peer
    Expand
There's Always More to Learn
Back -