• Questions and Problems 507

Section 13-4

17. What are three QoS issues for a VoIP network?18. What causes jitter in the received signal?19. How can the effects of jitter be minimized?20. When does buffering the received data packets not work in VoIP?21. What is network latency?22. What causes network data traffic congestion?23. What is WRED, and what is its purpose?24. What is the basic form of queuing?25. What is WFQ, and what is its purpose?26. What is the purpose of priority queuing?27. Which queuing technique reserves channel bandwidth for selected data traffic?

Section 13-5

28. What is the purpose of the basic codes used by the NBX call processor?29. Which code identifies voice data packets?30. What does the code 0x52 identify?31. What is the purpose of multicasting in IP telephony?

Critical Thinking

32. Prepare a technical memo to your supervisor that explains how VoIP can be im-plemented on your local network.

33. Use the Internet to find out what queuing systems are currently recommendedfor data traffic.