computer networks

21. Which of the following statements about MAN and WAN services is (are) true? A. Organizations must select the MAN and WAN services they sign up for based on key requirements such as data rates, security and availability B. Virtual Private Networks require the use of a software or a device that encrypts data sent between remote networks C. Organizations must always use a router to connect their networks to any MAN or WAN service D. a and b E. a,b and c 22. are companies that build a telecommunications infrastructure from which other organizations can lease services for MANs and WANs. A. Integrated service providers B. Common carriers C. Cloud computing providers D. Cloud service carriers E. None of the above 23. Which of the following statements about MAN and WAN services is (are) true? A. VPN is recommended for networks with moderate data rate requirements if cost is an issue B. VPN is recommended for networks with moderate data rate requirements if predictable response time and/or availability of the service are/is less of an issue C. Dedicated circuits networks are best recommended for networks with higher data rate requirements whereas packet-switched networks are best recommended for networks with lower data rate requirements D. a and b E. a,b and c 24. Which of the following statements about MAN and WAN services is (are) true? A. Packet switched networks enable packets from separate organizations to be sent over a same virtual circuit B. Ethernet can be recommended for networks with low, moderate, high and very high data rate requirements C. T-line services offer nominal data rates varying from 64kbps to about 45Mbps D. All of the above E. None of the above 25. Which of the following statements about network security is (are) true? A. A threat scenario describes for each IT asset a relevant threat, the likelihood of its occurrence and its potential consequences B. Security controls must be periodically reviewed by those who implemented them to ensure they are effective c. During the creation of a threat scenario, it is the responsibility of the IT managers to define risk measurement criteria to examine how a particular threat affects their organizations D. a and b E. a,b and c