Packet and Circuit Switching - Communication Theory - Lecture Slides, Slides of Data Communication Systems and Computer Networks

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Packet and Circuit Switching

Chapter Objectives

• Explain the concept of packet switching
• Give sample application areas of packet switching
• Describe circuit switching
• Compare and contrast packet switching with circuit switching

Module

Packet Switching

Packet Switching Preview

• Explain the concept of a path or a route taken by a

packet

• Study the difference between static and dynamic

paths?

• Relate appropriately the terms packet switching and

circuit switching to the terms dynamic and static

paths

• Explore the path taken by a packets in dynamic

routing when a packet travels from its origin to its

destination

Packet Switching Network

Los

Angeles

New

York

Packet 2

Packet 1 Miami

Salient Points of Packet Switching

• Path
  • Each packet may take a different path to its destination
  • Best path is heuristically determined at each node
• Packet switching
  • Path may be switched among packets
  • Hence, the term packet switching

End of Module

Module

Advantages and Disadvantages of Packet Switching

Questions (continued)

• What are the implications of packet switching to the transmission of audio and video in real time?
• How are the above problems addressed in streaming?

Major Advantages

• Better utilization of the network segments in terms of the usage of the network paths
• Ability to engage in multiple communication sessions

Support for Multiple Communication Sessions

Los

Angeles

New

York

Miami

Las

Vegas

Session 1

Session 2

Disadvantage or a Concern

• Packets may not arrive at their destination in the order in which they were originally transmitted
• The above possibility exists because of the different paths that are taken by the different packets

Packet Assembly

• Packets are assembled to preserve the order of transmission
• Packets arriving earlier are held in a buffer
• The order of arrival is critical and in certain cases the order is time sensitive as well

Transmission of Audio and Video in Packet

Switching

• Transmission of audio and video are time sensitive
  • Timely arrival of packet is important
• The process that would ensure the orderly and

timely arrival of data packets is known as streaming

• Streaming also compresses the data to minimize

bandwidth requirements thus ensuring that the

packets have adequate bandwidth to travel to the

destination in the order in which they are supposed

to arrive at the destination