NETW 250 Week 8 Final Exam New

BUY NETW 250 Week 8 Final Exam New

1. (TCO 1) ITU recommendation G. 711 is also referred to as _____ (Points : 5)

2. (TCO 1) What’s a typical amount of downtime associated with PSTN business services? (Points : 5)

3. (TCO 2) Which circuit-switched Private Branch Exchange (PBX) hardware allows internal phones and extensions to be connected to the PBX? (Points : 5)

4. (TCO 2) An end user of a(n) _____ uses line keys on the phone panel to select and access telephone company lines. (Points : 5)

5. (TCO 5) Which transport layer protocol is not used by voice packets in VoIP? (Points : 5)

6. (TCO 5) In the RTP header, _____ is used by the receiver to detect lost packets and to ensure that received packets are played back in proper order? (Points : 5)

7. (TCO 4) Which of the following audio codecs, in its original form, requires 64 Kbps of bandwidth? (Points : 5)

8. (TCO 4) Which of the following audio codecs, in its original form, requires the least amount of bandwidth? (Points : 5)

9. (TCO 5) Which of the following techniques help reduce VoIP bandwidth consumption? (Points : 5)

10. (TCO 3) Which of the following VoIP equipment is typically seen in a residential environment? (Points : 5)

11. (TCO 6) Which SIP method/response is typically generated to signal the end of a call session or dialog? (Points : 5)

12. (TCO 6) Which SIP method/request or response is shown below?

13. (TCO 6) In H.323 call signaling, _____ is used for terminals to exchange capabilities and preferences such as audio and video codecs during a call setup. (Points : 5)

14. (TCO 6) Which of the following is not a typical function of VoIP gateways? (Points : 5)

15. (TCO 7) Which of the following facts about Local Number Portability (LNP) is not correct? (Points : 5)

16. (TCO 7) Which of the following is a telephony feature that was made possible by VoIP? (Points : 5)

17. (TCO 8) What’s the name of the gateway interface/port that connects an analog phone? (Points : 5)

18. (TCO 8) Which of the following is typically required to connect SIP trunks to legacy PBXs and analog phones? (Points : 5)

19. (TCO 9) 200 seconds of total holding time during the Busy Hour generates a traffic load of _____ (Points : 5)

20. (TCO 9) Given that the targeted call blocking probability remains the same, which of the following PBX systems will support the least amount of traffic during the Busy Hour? (Points : 5)

21. (TCO 12) Sending an INVITE message to every phone number on a network in search of vulnerable devices based on received responses is referred to as _____ (Points : 5)

22. (TCO 12) Even if the voice traffic is encrypted, an intruder may capture and interpret _____ to discover who calls whom, when calls involve specific phones, and other information.(Points : 5)

23. (TCO 11) Network connectivity is a(n) _____ a good user experience on VoIP services. (Points : 5)

24. (TCO 11) Which of the following is not correct about echo in a voice call? (Points : 5)

25. (TCO 10) IEEE 802.1p defines eight priority classes for _____ prioritization. (Points : 5)

26. (TCO 13) Which of the following could be an indicator of high-end desktop IP phones? (Points : 5)

27. (TCO 13) Having a third-party assume all PBX management responsibilities is referred to as a(n) _____ solution. (Points : 5)

28. (TCO 13) What does this formula calculate?

(the expected returns from a project – the cost of implementing a project) / the amount of time required to complete the project. (Points : 5)

1. (TCO 5) ABC Inc. replaced its legacy circuit-switched PBX with an SIP-based VoIP system on its Ethernet LAN. When capturing and observing voice packets using Wireshark, which header contains the sequence number and time stamp information needed for playing back the audio at the receiving end? Describe, in one

2. (TCO 5) The IT department of ABC Inc. decides to use the G. 711 codec on its local VoIP telephony network. What’s the payload bit rate of G. 711? What does the payload bit rate mean? Explain, in one paragraph, how increasing and reducing the payload size of voice packets affects the required bandwidth per VoIP conversation, respectively. (Points : 10)

3. (TCO 6) Explain, in a couple of paragraphs, the origin and history of the SIP protocol and the H.323 protocol suite. What are the most noticeable characteristics of each? What are some of their cons? (Points : 10)

4. (TCO 10) Explain, in one paragraph, layer 2 prioritization and its priority classes. Explain, in one paragraph, layer 3 prioritization and its precedence levels. If a company plans to switch to VoIP, what should the IT department look for in the switches and routers on its network? (Points : 10)

5. (TCO 9) Use the Erlangs and VoIP Bandwidth Calculator athttp://www.erlang.com/calculator/eipb/ to complete the following question.

ABC Inc. is planning to lease a 512 Kbps frame relay connection between two PBXs from two branch locations. The audio codec used on the trunk is G.729A with a 20-millisecond packet duration. Assume the targeted call blocking probability for ABC Inc. is 1% (i.e., 0.01). How much traffic volume/load (in Erlangs) can this trunk support?

120 call attempts, with an average call duration of 10 minutes during the Busy Hour have been observed on the connection. What’s the current traffic volume/load (in Erlangs) on this trunk connection? Compare the current traffic volume/load to the supported traffic volume/load calculated above. Does the frame relay trunk have enough capacity to support the current traffic volume/load? (Points : 10)

6. (TCO 11) ABC Inc. is re-evaluating the end-to-end delay budget of its cross-country VoIP services. In one paragraph, name at least two components (i.e., devices or processes) that contribute to the end-to-end latency budget