Network Transmission Methods: Packet Switching vs Circuit Switching

• There are two types of network (referring to the entire network, not just layer 3) transmission methods.
• Packet Switching: Transmission unit is packets
• Circuit Switching: Transmission unit is continuous bit streams

Circuit Switching

• Transmission Unit: Continuous bit stream
• Connection Method: Establishes a dedicated circuit between sender and receiver before communication
• Operating Layers: Sets up and manages circuits at the physical layer (Layer 1 - bit units) and data link layer (Layer 2 - frame units)
• Characteristics: Once a circuit is established, it is used exclusively until communication ends
• Advantages: Guaranteed constant bandwidth, predictable delay time
• Disadvantages: Circuit utilization may be low, setup time required
• Example: Traditional telephone system (PSTN)

Packet Switching

• Transmission Unit: Packets
• Connection Method: Divides data into packet units and transmits each independently
• Operating Layer: Processes packets and performs routing at the network layer (Layer 3)
• Characteristics: Each packet can be transmitted through different paths
• Advantages: High circuit efficiency, multi-user support
• Disadvantages: Possibility of packet loss, variable delay time

Datagram Method

• Transmits independent packets along with headers
• Connectionless switching method

Virtual Circuit Method

• Sets up a logical circuit and transmits packets
• Connection-oriented switching method

Connectionless vs Connection-oriented Comparison