1 / 36

Homework

Homework. Chapter 14: HW 22, 24, 27, 28, 29, 31, 34,36,45,58, 59 a, b, c. Chapter 14 Switching. Circuit Switching Packet Switching Virtual circuit packet switching Datagram packet switching Message Switching. Switch.

rayya
Télécharger la présentation

Homework

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Homework • Chapter 14: • HW 22, 24, 27, 28, 29, 31, 34,36,45,58, 59 a, b, c

  2. Chapter 14Switching • Circuit Switching • Packet Switching • Virtual circuit packet switching • Datagram packet switching • Message Switching

  3. Switch • A hardware/software device capable of providing temporary connection among devices linked to the switch.

  4. Circuit switch may have n inputs and m outputs

  5. Switched Network

  6. VC approach Datagram approach Switched VC Permanent VC

  7. Circuit-Switched Network For mesh connection: No. of connections= n/2(n-1)=21 For point-to-point connection: No. of connections= n*m=12 Four switches are used to connect computers on the left to Computers on the right

  8. CircuitSwitching Networks • Dedicated circuit must be established first. • Data is transferred. • Data is transferred in bit streams. • Circuit is terminated • Example: (Public Switched Telephone Network, PSTN)

  9. CircuitSwitching Networks • Suitable for voice transmission. • Two devices must have the same data transmission rate. • Inflexible (once circuit is established, all data must follow the same path regardless of network conditions) • Not suitable for bursty traffic. • Circuits can be blocked. • You are charged for the circuit time. • The use of bandwidth may not be efficient.

  10. CircuitSwitching Technologies • Space-divisions switching • Crossbar switches • Multistage switches • Time-divisions switching

  11. Crossbar Switch

  12. Advantages of Crossbar Switch • Calls can not be blocked • Connection is instantaneous • Suitable for small number of inputs/outputs.

  13. Disadvantages of Crossbar Switch • The number of cross-points increases by approximately the square of the input/output devices. • Impractical for large number of inputs/outputs. • Inefficient use of the available circuits

  14. Multistage Switch 1 1 2 5 6 10 11 15 No. of crosspoints=3x(5x2)2*2x(3x3)+3x(2x5)=78 Single stage 15x15=225

  15. Disadvantage of Multistage Switch • Blocking

  16. Switching Path

  17. Switching Path

  18. Time-Division Switches • TDM is used to achieve switching. • Two TDM methods used are: • Time-slot interchange • TDM bus • Synchronous • Asynchronous

  19. TDM without Time-Slot Interchange (TSI)

  20. TDM with TSI

  21. Time-Slot Interchange (TSI)

  22. Advantage and Disadvantage of Time-Division Switching • Advantage: • It does not need crosspoints. • Disadvantages: • Processing time (data must be stored in RAM, retrieved, and processed)

  23. TDM Bus • I/O lines connected to high speed bus through I/O gates. • I/O lines are assigned time slot. • Devices can transmit during their assigned time slot. • One input gate is closed and only one output gate is closed during each time slot.

  24. Circuit Switching • Total transmission time • Call setup time • Signal propagation time • Data transmission time • ttot=ts+t prop.+ttrans.

  25. Circuit Switching (example) • The speed of propagation on a TDM bus is 0.8c, its length is 1 m, and the data rate is 500 Mbps. Calculate the total time to transmit 10 Mbytes of data. • ttot=ts+t prop.+ttrans.

  26. Circuit Switching Networks (review) • Suitable for voice transmission. • Two devices must have the same data transmission rate.(constant rate) • Not suitable for bursty traffic. • Inflexible (once circuit is established, all data must follow the same path regardless of network conditions) • Circuits can be blocked. • You are charged for the circuit time. • The use of bandwidth may not be efficient.

  27. Packet Switching Datagram approach VC approach Switched VC Permanent VC

  28. Packet Switching Networks • Suitable for audio, video, data transmission. • Two devices with different transmission speeds can exchange data. (variable data rate) • Priorities can be assigned. • Suitable for bursty traffic. • Circuits can not be blocked.

  29. Switched Virtual Circuit

  30. Switched Virtual Circuit

  31. Switched Virtual Circuit

  32. Virtual Circuit Packet SwitchingNetworks • Total transmission time • Call setup time for VC • Signal propagation time • Packets transmission time • ttot=ts+t prop.+ttrans.

  33. Datagram Approach

  34. Datagram Packet SwitchingNetworks • Total transmission time • Signal propagation time • Packets transmission time • ttot=t prop.+ttrans.

  35. Datagram Approach, Multiple Channels

  36. Message Switching

More Related