1. Communication Networks NETW 501 Tutorial 4
Prepared by: Eng. Minar El-Aasser

2. 1. Circuit Establishment
Circuit Switching
1. Circuit Establishment
2. Information Transfer
3. Circuit Disconnect
Switch C
Switch A
Switch D
Physical copper
connection set up
when call is made
Switch B
Switching offices

3. Event Timing (Circuit Switching) - PSTN
Switch A
Switch B
Switch C
Switch D
5Tp Tp
Circuit Establishment Tt
Data Transfer
Circuit Disconnect
Time
Time
Time
Time
Time
Time

4. Packet Switching Router E Router C Router A Router D Router Congested
Router B
Router F

5. Event Timing (Packet Switching) -Http
Router A
Router B
Router C
Router D Tp Tt 1 1
TPr 2 2 1 1
TPr 2 2 1
Data Transfer 1
TPr 2 2 1 1
TPr 2 2 1 1 2 2
Time
Time
Time
Time
Time
Time
TPr  Processing Time

6. Virtual Circuit Packet Switching
1. Connection Establishment
2. Information Transfer
3. Circuit Disconnect
Router E
Router C
Router A
Router D
Router B
Router F

7. Event Timing (Virtual Circuit Packet Switching) – VOIP (Voice Over IP)
Router A
Router B
Router C
Router D
Connection Establishment 1 1
TPr 2 2 1 1 2
TPr 2 1
Data Transfer 1
TPr 2 2 1 1 2
TPr 2 1 1 2 2
Connection Release
Time
Time
Time
Time
Time
Time

8. Questions?