376 CHAPTER 8: Wide Area Networking What is the biggest difference between packet-switched and circuit-Q: switched networks? The biggest difference between packet-switched and circuit-A: switched networks is that circuit switching requires someone to configure and set up each individual connection before it is used, where as packet switching allows for dynamic setup and an always-on connection. Why is packet-switching technology so much more desirable?Q: Packet switching is more desirable than circuit switching because A: packet switching divides the transmitting data into packets and given sequence numbers so that they can all be put back together again in the right order at the destination. The benefit of this is that each packet can take a different route to get to its destination. Once there, the message will be recompiled and take its original form. Circuit switching does not allow for this kind of flexibility because it is not an always-on switching method. Should I memorize the speeds of WAN protocols for the test?Q: Understanding the different kinds of WAN protocols and proper-A: ties, how they differ and why is vital to answering the CompTIA Network+ exam question correctly. There will be plenty of questions on the exam that are scenario-based in which you have to know the speeds of various WAN protocols and properties. Is Frame Relay more flexible compared to FDDI?Q: Frame Relay is more flexible than FDDI because if an organization A: needs to communicate to their remote sites, they can add or take away channels as needed depending on how much bandwidth is required. With FDDI, the idea is to provide high-speed service to all stations connected to the ring. If you no longer need such services at one remote site, you cannot change the fixed bandwidth without affecting all sites. What kind of organizations use Optical Carrier (OCx) links?Q: The SONET standard defines a hierarchy of interface rates that A: allow data streams at different rates to be multiplexed (as shown in Table 8.1). SONET establishes OCx levels from 51.8 Mbps to 40 Gbps. OCs are usually implemented for large organizations like ISPs to transmit huge amounts of network traffic while allowing for types of data like voice and video to be sent and received around the world in seconds. Self Test 377 What is the difference between ADSL and SDSL?Q: The difference between ADSL and SDSL is that homes and small A: businesses use ADSL whereas larger companies use SDSL due to the increased upstream and downstream data speeds. SDSL operates at approximately 2 to 2.5 Mbps both downstream and upstream. ADSL generates downstream speeds of approximately 8 Mbps and upstream speeds of up to 640 Kbps. Is ISDN the same thing as dial-up?Q: Both use dialing, but dial-up is based on the telephone system and A: uses analog lines, whereas ISDN (and DSL) are both digital. For the Network+ exam, you need to have a clear picture of each technology and its basics, and you must be able to differentiate between them. What is the main difference between a satellite and WWANs?Q: The main difference is that satellites use low, medium, and geosyn-A: chronous Earth orbit satellites in space to transfer data; whereas WWANs use antennas on Earth, not in space, to transfer data. SELF TEST As the primary lead on your company’s helpdesk, you are asked to 1. help resolve a problem call with an ISDN line. A customer wants to upgrade an existing ISDN line because it’s currently too slow. Right now, he is using a single BRI ISDN circuit-switched B channel. From the available choices, what should his transmission rate be? A. 56 Mbps B. 64 Kbps C. 128 Kbps D. 256 Mbps As the network administrator for your company, you are asked by 2. your CIO to design and deploy a data link between two offices of your company. There are 10 employees located in each office. Your main concerns are the speed of the connections, the reliability of transferring of data, and the cost. Which solution should you implement? (Choose one) A. Place a modem on a server in each office so they can connect. B. Connect an ISDN circuit to each workstation in both locations. 378 CHAPTER 8: Wide Area Networking C. Use an ISDN circuit connected to a dedicated location or server in each building. D. Have each workstation at both locations use a modem to connect to opposite offices. You are the IT manager for rsnetworks.net. As the person respon-3. sible for recommending the right technology, what would you select as the solution to provide the fastest connectivity? (Select one) A. T3 B. T1 C. ISDN BRI D. Cable modem You want to connect a remote office to a corporate network. The 4. only available service is an analog dial-up line provided by the local telephone company. What device would you need to implement to use this analog dial-up solution? A. CSU/DSU B. ISDN adapter C. Modem D. NIC As the Network Manager for rsnetworks.net, you need to imple-5. ment a solution that will allow for sporadic connection to the Internet. Your only requirement is that you find a solution that will provide a connection of up to 128 Kbps to the Internet, only when needed. Which solution should you implement? A. T1 B. T3 C. 56 Kbps D. BRI ISDN As a network manager for your company’s high-speed network, you 6. are looking to implement a new line from a remote site (Chicago) to the company’s core hub (New York) where the mainframe is located. The mainframe is where all the company’s sales orders are placed daily. The hub site is where all sites get their Internet access from, and where they upload and download files to and from. Connection to this mainframe 24 hours a day is essential to meeting the business plan. You have just heard from your systems Self Test 379 engineer that users are no longer able to access the mainframe from the remote sites; the users at the core site are still able to access the mainframe. Within minutes, the connection is restored and all users are able to access the mainframe once more. From careful analysis, you uncover that during the time that the remote users were not able to access the mainframe, one user had been downloading a very large file from the Internet to the remote site user’s PC. You find that the user was downloading a legitimate file and will be doing so each day. You cannot afford this type of network slowdown each day, so you decide to allow for the upgrading of the line. It’s currently at 128 Kbps using ISDN BRI. You have found that after careful analy- sis of the remote sites’ usage patterns and looking over the docu- mentation of the current network, an upgrade of approximately 1.5 Mbps is needed across all links. Which technology would you implement? (Choose one) A. ADSL B. E1 C. LAN adapter D. T1 The PSTN is the analog-based telephone system we have come 7. to be very familiar with today. What are some of the features of PSTN? (Choose all that apply) A. Compared to DSL and ISDN, it is inexpensive B. Worldwide installation base in use and readily available C. Easy to use and configure D. Transfer rates of 64 Kbps You are a network administrator at your company. Your company 8. has a number of sales and marketing users who work remotely and telecommute from home or from sales meetings. These users dial into a remote access service (RAS) server to access the corporate headquarters. One day, one of the sales users dials up the RAS server to connect to the corporate headquarters network to access a few files. The sales user dials up the RAS server and cannot con- nect. The sales user reports that there is no dial tone. What is the cause of the problem? (Choose one) A. Telephone company problem. B. The modem does not support the PC. 380 CHAPTER 8: Wide Area Networking C. The modem settings are set incorrectly. D. There are no settings configured within Windows. You are the network technician at your company. You are configur-9. ing a Windows NT 4.0 laptop for dial-up networking. The laptop will be used by a telecommuter. The telecommuter will use the laptop to dial into a Microsoft Windows NT 4.0 RAS server. Once connected, the telecommuter will need access to a UNIX machine. What should you install on the laptop? (Choose two) A. TCP/IP Protocol B. RDP C. VPN D. Dial-up networking You are a consultant looking over network documentation for a 10. small company with one core site and two remote sites. Router A shows the location of the corporate headquarters where there is also a link out for Internet access and another remote site configured to also connect to the core. From Figure 8.8, what type of WAN tech- nology is in use based on the information shown for Link A? A. DSL B. T3 C. T1 D. FDDI FIGURE 8.8 WAN Technology. Router A Corporate HQ Link A Speed � 1.544 Mbps Link A Router B Remote Site Link B Router C Remote Site Self Test 381 You are the network manager and you just sat down for lunch at your 11. desk. You notice that you have to troubleshoot a circuit-switching network from a note written by your boss. Your boss has also placed a picture of this circuit-switched network on your desk. What is the usual WAN technology associated with circuit-switched networks? A. Internet Services Digital Network B. Integrated Services Digital Netware C. Integrated Services Diagram Network D. Integrated Services Digital Network What is the difference between ISDN and dial-up?12. A. Both use dialing, but dial-up is based on the WAN and uses ana- log lines, whereas ISDN (and DSL) are both digital. B. Neither use dialing, but dial-up is based on the telephone system and uses analog lines, whereas ISDN (and DSL) are both analog. C. Both use dialing, but dial-up is based on the telephone system and uses digital lines, whereas ISDN (and DSL) are both digital. D. Both use dialing, but dial-up is based on the telephone system and uses analog lines, whereas ISDN (and DSL) are both digital. You just got hired on to a Mobile Telecommunication Cellular 13. company and your first assignment is to teach your junior network engineers what WIMAX is. What description best describes what WIMAX is and stands for? A. WIMAX stands for WWW Interoperability for Microwave Access. It is based on IEEE 802.16 standards, or Broadband Wireless Access. An acceptable rule of thumb is that WIMAX will sustain 70 Mbps transmission rates at approximately 15 miles. B. WIMAX stands for Worldwide Interoperability for Microwave Access. It is based on IEEE 802.11 standards, or Broadband Wire- less Access. An acceptable rule of thumb is that WIMAX will sustain 70 Mbps transmission rates at approximately 30 miles. C. WIMAX stands for Worldwide Internet for Microwave Access. It is based on IEEE 802.16 standards, or Broadband Wireless Access. An acceptable rule of thumb is that WIMAX will sustain 70 Mbps transmission rates at approximately 15 miles. D. WMAX stands for Worldwide Interoperability for Microwave Access. It is based on IEEE 802.16 standards, or Broadband Wire- less Access. An acceptable rule of thumb is that WIMAX will sustain 70 Mbps transmission rates at approximately 30 miles. 382 CHAPTER 8: Wide Area Networking FIGURE 8.9 What is Figure 8.9 depicting? Choose the best answer.14. A. WIMAX similar network B. Satellite-based network C. Wireless Wide Area Network D. Wide Area Network technology 15. How far do LEOs and MEOs orbit above the earth? A. LEOs 1,800 to 2,000 miles; MEOs 1,800 to 2,000 miles B. LEOs 1,800 to 2,000 miles; MEOs 2,000 to 10,000 miles C. LEOs 1,800 to 2,000 miles; MEOs 9,000 to 10,000 miles D. LEOs 9,000 to 10,000 miles; MEOs 9,000 to 10,000 miles Self Test Quick Answer Key 383 SELF TEST QUICK ANSWER KEY C1. C2. A3. C4. D5. D6. A, B, and C7. A8. A and D9. C10. D11. D12. D13. B and D14. C15. This page intentionally left blank 385 CHAPTER 9 Security Standards and Services EXAM OBJECTIVES IN THIS CHAPTER HARDWARE AND SOFTWARE SECURITY DEVICES 386 SECURITY ZONES 405 NETWORK PORTS, SERVICES, AND THREATS 416 NETWORK ACCESS SECURITY 431 INTRODUCTION In today’s network infrastructures, it is critical to know the fundamentals of basic security infrastructure. Before any computer is connected to the Internet, planning must occur to make sure that the network is designed in a secure manner. Many of the attacks that hackers use are successful because of an insecure network design. That is why it is so important for a security professional to use secure topologies and tools like intrusion detection and prevention to help thwart attacks. Another security mechanism that may be deployed is a virtual local area networks (VLANs). VLANs are responsible for securing a broadcast domain to a group of switch ports. This relates directly to secure topologies because VLANs allow for different Internet Protocol (IP) subnets to be configured in different port groupings and separated, either by routing or by applying an access control list (ACL). This allows for separation of network traffic; for example, the Executive group can be isolated from the general user popula- tion on a network, which can aid in securing the infrastructure. Test Day Tip An ACL is a list of users that have permission to access a resource or modify a file. ACLs are used in nearly all modern-day operating systems (OSs) to determine what permissions a user has on a particular resource or file. . kinds of WAN protocols and proper-A: ties, how they differ and why is vital to answering the CompTIA Network+ exam question correctly. There will be plenty of questions on the exam that are. to 640 Kbps. Is ISDN the same thing as dial-up?Q: Both use dialing, but dial-up is based on the telephone system and A: uses analog lines, whereas ISDN (and DSL) are both digital. For the Network+. rates to be multiplexed (as shown in Table 8.1). SONET establishes OCx levels from 51.8 Mbps to 40 Gbps. OCs are usually implemented for large organizations like ISPs to transmit huge amounts