Q&A
As mentioned in the Introduction, you have two choices for review questions. The questions that follow next give you a more difficult challenge than the exam itself by using an open-ended question format. By reviewing now with this more difficult question format, you can exercise your memory better, and prove your conceptual and factual knowledge of this chapter. You can find the answers to these questions in Appendix A.
The second option for practice questions is to use the CD-ROM included with this book. It includes a testing engine and more than 200 multiple-choice questions. You should use this CD-ROM nearer to the end of your preparation, for practice with the actual exam format.
Compression Tools
| 1. | Describe what is compressed, and what is not compressed, when using payload compression. Be as specific as possible regarding headers and data.
| | 2. | Describe what is compressed, and what is not compressed, when using TCP header compression. Be as specific as possible regarding headers and data.
| | 3. | Describe what is compressed, and what is not compressed, when using RTP header compression. Be as specific as possible regarding headers and data.
| | 4. | Suppose a packet is sent across a network with no compression. Later, a packet of the exact same size and contents crosses the network, but payload compression is used on the one serial link in the network. Describe the difference in bandwidth and delay in the network between these two packets.
| | 5. | How much bandwidth should a G.729 call require over Frame Relay, and how much should be required with cRTP?
| | 6. | When TCP header compression is used, what is the range of sizes of the part of the frame that can be compressed, and what is the range of sizes for this field of the frame after compression?
| | 7. | When RTP header compression is used, what is the range of sizes of the part of the frame that can be compressed, and what is the range of sizes for this field of the frame after compression?
| | 8. | The configuration snippet shows the configuration on two routers, R1 and R2, on the serial interfaces attached to a common serial link. Will VoIP RTP sessions be compressed, or even work at all? Explain why or why not in relation to what has been configured on the two routers.
| | 9. | The configuration snippet shows the configuration on two routers, R1 and R2, on the serial interfaces attached to a common serial link. Will telnet connections be compressed, or even work at all? Explain why or why not in relation to what has been configured on the two routers.
| | 10. | The configuration snippet shows the configuration on two routers, R1 and R2, on the serial interfaces attached to a common serial link. Will web TCP connections be compressed, or even work at all? Explain why or why not in relation to what has been configured on the two routers.
| | 11. | Without creating all the exact configuration commands, generally describe the types of changes to the configuration on R2 that would be required in order to ensure that none of the flows would fail due to one router wanting to compress, and the other one not wanting to compress.
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LFI Tools
| 12. | List the words represented by the abbreviation LFI.
| | 13. | Describe the main motivation for LFI tools in relation to the support of data, voice, and video traffic.
| | 14. | To achieve a 20-ms serialization delay on a 128-kbps link, how long can the fragments be?
| | 15. | To achieve a 10-ms serialization delay on a 64-kbps link, how long can the fragments be?
| | 16. | To achieve a 10-ms serialization delay on a 56-kbps link, how long can the fragments be?
| | 17. | To achieve a 30-ms serialization delay on a 128-kbps link, how long can the fragments be?
| | 18. | Suppose that a 1500-byte packet exits a 56-kbps serial interface, and LFI is not used. How long is the serialization delay?
| | 19. | Which queuing tools can you enable directly on a serial interface when using multilink Point-to-Point Protocol with link fragmentation and interleaving (MLP LFI), in order to interleave packets?
| | 20. | Which queuing tools can you enable with FRTS in order to actually interleave the traffic?
| | 21. | Explain the scheduling logic used by MLP LFI to determine which packets can be interleaved in front of fragments of other packets.
| | 22. | Suppose a 1500-byte packet arrives and needs to be sent over an MLP bundle that has two active links. LFI has not been configured. Which link does the packet flow across to achieve MLP load balancing?
| | 23. | What command can you use to determine the fragment size used for MLP LFI? What is the only parameter of the command?
| | 24. | What command enables the interleaving feature of MLP LFI?
| | 25. | What commands list counters for the number of interleaved packets using MLP LFI?
| | 26. | What other QoS feature for Frame Relay must you enable when you also configure FRF.12?
| | 27. | What command enables FRF and sets the fragment size?
| | 28. | What command lists counters for the numbers of packets and bytes that were fragmented and unfragmented by FRF.12?
| | 29. | What command lists counters for the numbers of packets and bytes that would have been sent if FRF.12 fragmentation had not been performed?
| | 30. | What command lists counters for the number of packets that end up in the High and Normal Dual-FIFO siftware queues, when using FRF.12?
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