CompTIA’s Network+ certification Study Guide part 72 is a globally-recognized, vendor neutral exam that has helped over 235,000 IT professionals reach further and higher in their careers. The 2009 Network+ exam (N10-004) is a major update with more focus on security and wireless aspects of networking. Our new study guide has been updated accordingly with focus on network, systems, and WAN security and complete coverage of today’s wireless networking standards. | 696 Appendix C C. RF interference from other devices. D. All of the above. Correct answer and explanation D. All of these could be a problem. Structural interference such as thick walls metal between the access point and computer could cause a shortening of distance. EMI environmentally could cause a shortening of distance. RFI could also cause a shortening of distance. CHAPTER 6 THE OSI MODEL AND NETWORKING PROTOCOLS 1. Which OSI model layer is responsible for frame sequencing A. The physical layer B. The transport layer C. The data link layer D. The application layer Correct answer and explanation C. The data link layer combines bits into bytes and bytes into frames provides access to media using MAC addresses and error detection. Furthermore it provides sequencing of frames. Therefore answer C is correct. 2. You are a network technician assigned to install a new network hub. At which layer of the OSI model does a standard hub operate Select only one answer. A. Physical layer B. Data link layer C. Network layer D. Transport layer Correct answer and explanation A. Hubs operate at the physical layer of the OSI model. Therefore answer A is correct. 3. You are a network technician assigned to install a new network switch. At which layer of the OSI model does a standard switch or bridge operate Select only one answer. A. Physical layer B. Data link layer C. Network layer D. Transport layer Appendix C 697 Correct answer and explanation B. Switches and bridges operate at the data link layer of the OSI model. Therefore answer B is correct. 4. You are a network technician assigned to install a new network router. At which layer of the OSI model does a standard router operate Choose all that apply. A. Physical layer B. Data link layer C. Network layer D. Transport layer Correct answer and explanation C. Routers operate at the network layer of the OSI model. Therefore answer C is correct. Don t get caught up with choose all that apply as it s only a distracter. Pay close .