CH-11-12 Network Performance and Recovery – Network+ Guide to Networks : Chapter Notes

This Document Contains Chapters 11 to 12 Chapter 11 Network Performance and Recovery At a Glance Instructor’s Manual Table of Contents • Overview • Objectives • Teaching Tips • Quick Quizzes • Class Discussion Topics • Additional Projects • Additional Resources • Key Terms Lecture Notes Overview Throughout this text, students have learned about building scalable, reliable networks as well as selecting the most appropriate hardware, topologies, and services to operate a network. Students have also learned about security measures to guard network access and resources. In this chapter, they will learn how to optimize networks for today’s high-bandwidth needs, protect a network’s performance from faults and failures, and recover in the event a network experiences a minor outage or a more severe disaster. With proper adjustments, redundancies, and preparations, students can create and maintain a resilient network. Chapter Objectives After reading this chapter and completing the exercises, the student will be able to: • Use appropriate tools to monitor device and network events • Adjust device configurations to optimize network performance • Identify methods to increase network availability • Identify best practices for incident response and disaster recovery Teaching Tips Collecting Network Data 1. Define and describe the term network management. 2. Explain that network management can include: a. controlling user access to network resources b. checking for hardware faults c. ensuring optimized QoS for critical applications d. maintaining records of network assets and software configurations e. determining what time of day is best for upgrading a router, server, or application 3. Point out that several disciplines fall under the heading of network management. a. Emphasize that all disciplines share the goal of enhancing efficiency and performance while preventing costly downtime or loss. 4. Explain that ideally, network management accomplishes its goals by helping the administrator predict problems before they occur. 5. Point out that before a network professional can assess and make predictions about a network’s health, however, they must measure and understand the networks logical and physical structure and understand how it functions under typical conditions. Monitoring Tools 1. Define and explain a network monitor. Explain that a similar tool is known as a protocol analyzer, which can monitor traffic at a specific interface between a server or client and the network. 2. Use Figure 11-1 to discuss methods to monitor network traffic: a. wireless monitoring b. port mirroring c. in-line monitoring 3. Mention that to take advantage of network monitoring and analyzing tools, the network adapter installed in the machine running the software must support promiscuous mode. 4. Discuss the various places from which a network monitor may be obtained. 5. Point out that all network monitors tend to use similar graphical interfaces. 6. Describe the functions all network monitoring tools can perform. 7. Describe some additional functions that some network monitoring tools can perform. 8. Explain how capturing data can help you solve a problem. 9. Review some commonly used terms for abnormal data patterns and packets, along with their characteristics: a. runts b. giants c. jabber d. ghosts e. packet loss f. discarded packets g. interface resets 10. Point out that many devices come with embedded event logging tools and will store logs within their own systems. System and Event Logs 1. Explain how virtually every condition recognized by an operating system can be recorded. 2. Introduce the Windows-based system event log and point out that it can be easily viewed with Event Viewer application. 3. Define and describe the UNIX and Linux system log, known as syslog. 4. Explain that syslog defines two possible roles for computer participating in logging events: a. generator b. collector 5. Use Table 11-1 to discuss Linux and UNIX system log locations. 6. Point out that most UNIX and Linux operating systems provide a GUI application for easily viewing and filtering the information in syslog files. 7. Explain why using these logs for fault management requires thoughtful data filtering and sorting. Teaching Tip Demonstrate to the class where the event logs can be found on a Windows-based system. Open the logs to see the recorded information. SNMP Logs 1. Explain why organizations often use network management software. 2. Use Figure 11-6 to discuss the following entities that are part of a network management architecture: a. NMS (network management system) server b. managed device c. network management agent d. MIB (Management Information Base) 3. Define the term polling. 4. Explain how agents use SNMP (Simple Network Management Protocol). Discuss the different versions of SNMP. 5. Use Figure 11-7 to illustrate the relationship between a network management system and managed devices on a network. 6. Point out that a network management system can present an administrator with several ways to view and analyze the data. 7. Use Figure 11-8 to illustrate a map showing network status. 8. Explain the benefit and drawback of network management applications. 9. Explain why it is important to collect only useful data and not an excessive amount of routine information. Teaching Tip Navigate to the MRTG (Multi Router Traffic Grapher) Web site at http://oss.oetiker.ch/mrtg to demonstrate capabilities of the product. Performance Baselines 1. Define and explain the term baseline. 2. Explain what might be included in baseline measurements. 3. Use Figure 11-9 to illustrate an example baseline for daily network traffic over a six-week period. 4. Note that baseline measurements allow a network professional to compare future performance increases or decreases caused by network changes or events with past network performance. 5. Point out that the more data gathered while establishing a network’s baseline, the more accurate a prediction will be. 6. Describe why network traffic patterns might be difficult to forecast: a. Normal variations throughout the day, week, month, and different seasons b. Changes to the network that might be unpredictable in the resulting impact 7. Explain how a network professional gathers baseline data on the network. 8. Discuss the more common performance metrics used to analyze traffic: a. utilization b. error rate c. packet drops d. jitter Managing Network Traffic 1. Point out that after you’ve begun collecting data on traffic patterns and established reliable baselines, you must monitor your network’s status on an ongoing basis. 2. Define the term performance management. 3. Define the term fault management. Traffic Management 1. Define and describe the term traffic shaping (also called packet shaping). a. Include an explanation of traffic shaping goals. 2. Describe the techniques used in traffic shaping. a. Define and explain the term traffic policing. 3. Use Figure 11-10 to illustrate how traffic volume might appear on an interface without limits compared to an interface subject to traffic policing. 4. Describe the controversial example of traffic shaping that became known in 2007 with Comcast. 5. Define and explain traffic prioritization. Discuss some of the characteristics that can be used to prioritize traffic: a. Protocol b. IP address c. User group d. DiffServ flag in an IP packet e. VLAN tag in a Data Link layer frame f. Service or application QoS (Quality of Service) Assurance 1. Define a network’s QoS as group of techniques for adjusting the priority a network assigns to various types of transmissions. 2. Introduce students to DiffServ (Differentiated Service), which is a technique that addresses QoS issues by prioritizing traffic at Layer 3. 3. Discuss the two types of forwarding defined by DiffServ: a. EF (Expedited Forwarding) b. AF (Assured Forwarding) 4. Explain that CoS (Class of Service) is sometimes used synonymously with QoS, but there is a distinction. Discuss that distinction. 5. Mention that a network’s connectivity devices and clients must support the same set of protocol to achieve their QoS benefits. Quick Quiz 1 1. True or False: A protocol analyzer is used to monitor traffic at a specific interface between a server or client and the network. Answer: True 2. A _____ is a report of the network’s current state of operation. Answer: baseline 3. Packets that arrive at their destination but are dropped because issues such as buffer overflow and latency delayed them from beyond their usable time frame are known as which type of packet? a. ghost b. packet loss c. discarded packets d. packet reset Answer: C 4. Which network management protocol provides for both authentication and encryption? a. SMTP b. SNMPv1 c. SNMPv2 d. SNMPv3 Answer: D 5. The calculated percentage of how often bits are damaged is known as which of the following? a. error rate b. utilization c. packet drops d. jitter Answer: A Network Availability 1. Define and explain the term availability. 2. Explain that HA (high availability) refers to a system that functions reliably nearly all the time. 3. Use Table 11-2 to discuss the importance of measuring a system or network’s availability vs. downtime. Mention where how this information can be accessed in: a. Linux or UNIX: use the command uptime b. Windows: Task Manager Fault Tolerance 1. Introduce the concept of fault tolerance. 2. Discuss the differences between failures and faults. 3. Introduce students to the following terms: a. MTBF (mean time between failures) b. MTTR (mean time to repair) 4. Discuss the importance of implementing redundancy in the design of a network. Mention, however, that the main disadvantage of redundancy is its cost. 5. Describe the key to fault tolerance in network design. a. Provide examples of fault tolerant topologies. b. Use Figure 11-13 to demonstrate fully redundant T-1 connectivity 6. Explain how to achieve the utmost fault tolerance which will produce a capability known as automatic failover. 7. Discuss the following concepts: a. hot spare b. cold spare 8. Ensure students understand the function of link aggregation, which is a combination of multiple network interface or ports to act as one logical interface. Point out that this is also known as port aggregation on Cisco devices and NIC teaming on Windows devices. 9. Use Figure 11-14 to discuss the following advantages to link aggregation: a. increased total throughput b. automatic failover between the aggregated NICs c. load balancing 10. Use Figure 11-15 to demonstrate how link aggregation allows two workstations to communicate with a server at the same time. 11. Point out that many manufacturers now use LACP (Link Aggregation Control Protocol), which dynamically coordinates communications between hosts on aggregated connections. 12. Define a load balancer as a device dedicated to the task of distributing traffic intelligently among multiple computers. 13. Discuss clustering, which is a technique of grouping multiple devices so they appear as a cluster. Use Figure 11-17 in your discussion. 14. Briefly explain the common address redundancy protocol (CARP), which allows a pool of computers or interfaces to share one or more IP addresses. 15. Use Figure 11-19 to discuss the concept of distributed switching. Point out the following benefits: a. centralizes control of VMs b. simplifies network operations c. minimizes the chances for configuration errors Data Backup and Storage 1. Define the term backup and explain the benefits backups provide. 2. Discuss thing to keep in mind when designing and configuring a backup system. 3. Define a snapshot, which is a frequently saved, incremental backup of the data’s state at a specific point in time. 4. Point out that backing up data is not the same thing as redundancy. Discuss the differences between data backups and network storage technologies. 5. Introduce the concept of NAS (network attached storage). a. Define and describe NAS (network attached storage). 6. Describe advantages to using NAS: a. optimization b. adaptability c. expansion d. 7. Discuss the four most common types of RAID: a. RAID 0 b. RAID 1 c. RAID 5 d. RAID 10 8. Explain that more efficient alternatives have been developed. Discuss one of the examples, which is block level storage. Teaching Tip Students may find more information on network attached storage (NAS) at http://searchstorage.techtarget.com/definition/network-attached-storage 9. Introduce the concept of SANs (storage area networks). a. Define and describe SANs (storage area networks). b. Describe the fault tolerant advantages to using SANs. 10. Describe the following technologies used by SANs: • FC (Fibre Channel) • FCoE • iSCSI • IB (InfiniBand) 11. Use Figure 11-26 to illustrate a SAN using FC connected to a LAN. 12. Use Figure 11-28 to illustrate a SAN using FCoE to connect to a LAN. 13. Explain the installation advantage of SAN. 14. Explain the scalability advantage SAN provides. Point out where the use of SAN is most appropriate. Teaching Tip Students may read more information on SANs in the IBM Redbook: Introduction to Storage Area Networks at: http://www.redbooks.ibm.com/Redbooks.nsf/RedbookAbstracts/sg245470.html Power Management 1. Explain that part of network management is managing power sources to account for outages and fluctuations. 2. Mention that power surges, even small ones, can cause serious damage to sensitive computer equipment and can be one of the most frustrating sources of network problems. 3. Discuss the “Applying Concepts: AC and DC Power and Converters” section with your students. Be sure to define the four types of converters: • inverter • rectifier • transformer • voltage regulator 4. Describe power flaws that can damage equipment. a. Surge b. Noise c. Brownout d. Blackout 5. Explain how network administrators ensure that power remains available and problem free by installing a UPS (uninterruptible power supply). a. Define the term UPS (uninterruptible power supply). 6. Describe the varying characteristics of UPS systems. a. Explain the two general categories of UPSs: standby and online. b. Use Figure 11-30 to illustrate online UPSs installed on a rack. 7. Discuss the factors to consider when deciding the correct UPS for a network. a. Amount of power needed b. Period of time to keep a device running c. Line conditioning d. Cost 8. Introduce the concept of a generator. a. Explain characteristics of their use. 9. Describe how to calculate an organization’s crucial electrical demands to determine a generator’s optimal size. 10. Use Figure 11-31 to illustrate UPSs and a generator in a network design. Teaching Tip Provide an in-class demonstration by navigating to the APC Web site at http://www.apc.com/home/us/en/ to review commercially available backup equipment. Response and Recovery 1. Point out that training and preparation can make all the difference in your company’s ability to respond and adapt to disasters and security breaches. 2. Discuss the difference between an incident and a disaster. Incident Response Policies 1. Explain that incident response policies define the characteristics of an event that qualifies as a formal incident and steps that should be followed as a result. 2. Give examples of incidents that might qualify as a formal incident, such as: a. A break-in b. Fire or weather-related emergency c. Hacking attack d. Discovery of illegal content or activity on an employee’s computer e. Malware outbreak f. Environmental disaster 3. Describe the six-stage process in incident response: a. Preparation b. Detection and identification c. Containment d. Remediation e. Recovery f. Review 4. Point out that the response policy should identify member of a response team and discuss the suggested team roles: a. dispatcher b. technical support specialist c. manager d. public relations specialist Disaster Recovery Planning 1. Introduce the concept of disaster recovery, which is the process of restoring your critical functionality and data after an outage that affects more than a single system or a limited group of users. 2. Mention that the goal of a disaster recovery plan is to ensure business continuity. 3. Discuss sections of a disaster recovery plan relating to computer systems that should be included. 4. Note the benefit of having a comprehensive disaster recovery plan. Disaster Recovery Contingencies 1. Introduce and explain disaster recovery contingency. 2. Use Figure 11-32 to discuss how disaster recovery contingencies are divided into the following categories: a. cold site b. warm site c. hot site Data Preservation 1. Explain that data being collected might be presented in a court of law for the purpose of prosecuting an instigator of illegal activity. Discuss the importance of careful data collection methods and policies. 2. Discuss the steps that should be taken in order to safeguard information until a first responder or incident response team can take over collection of evidence: a. Secure the area b. Document the scene c. Monitor evidence and data collection d. Protect the chain of custody e. Monitor transport of data and equipment f. Create a report Quick Quiz 2 1. True or False: An advantage to using NAS is that it can be easily expanded without interrupting service. Answer: True 2. What type of power flaw is defined as a momentary increase in voltage due to lightning strikes, solar flares, or electrical problems? Answer: surge 3. Which of the following is a battery-operated power source directly attached to one or more devices and to a power supply that prevents undesired features of the wall outlet’s A/C power from harming the device or interrupting its services? a. UPS b. generator c. transformer d. SONET Answer: A 4. True or False. A cold site is a place where the computers, devices, and connectivity necessary to rebuild a network exist, and all are appropriately configured, updated, and connected to match a network’s current state. Answer: False 5. What type of plan accounts for the worst-case scenarios, from a far-reaching hurricane to a military or terrorist attack? a. continuity b. contingency c. disaster recovery d. survivability Answer: C Class Discussion Topics 1. Ask student to discuss some of the network monitoring tools they have used in their organization. Ask them to elaborate on any specific issues that were resolved using one of the network monitoring tools covered in this chapter. 2. Ask students to discuss data backup procedures that are in place at their organization. Do they have any examples of where having up-to-date backups or another form of redundancy saved the organization time and money? Additional Projects 1. Hundreds of network monitoring tools exist. You can purchase or download free network monitoring tools developed by software companies. Students should go to the Web and research three network-monitoring tools, and provide a report of their findings. The report should include a comparison of the products. 2. Have the student select and research one topic from the NAS or SAN subject areas. Ask them to include an analysis of a current commercial or free product implementing the technology. The final report should consist of the following sections: Introduction, Background and History, Technical Specifications, Implementation, Barriers, and Summary. Additional Resources 1. Network Baselining http://www.webopedia.com/TERM/N/network_baselining.html 2. Windows Event Log, Syslog, and SNMP http://www.tntsoftware.com/eventlogproducts/servermonitoring/logmanagement.aspx 3. Cisco Traffic Shaping and Policing Overview http://www.cisco.com/c/en/us/td/docs/ios/12_2/qos/configuration/guide/fqos_c/qcfpolsh.html 4. IBM Storage Area Network (SAN) http://www-03.ibm.com/systems/storage/san 5. IBM Redbook: SAN - Redundancy and Resiliency Explained http://www.redbooks.ibm.com/abstracts/tips0033.html Key Terms For definitions of key terms, see the Glossary near the end of the book.  AF (Assured Forwarding)  automatic failover  availability  backup  baseline  business continuity  CARP (Common Address Redundancy Protocol)  chain of custody  clustering  cold site  CoS (Class of Service)  delay-sensitive  differential backup  DiffServ (Differentiated Services)  disaster  disaster recovery  distributed switching  DSCP (Differentiated Services Code Point)  dual power supplies  EF (Expedited Forwarding)  error rate  event log  Event Viewer  failure  fault  fault management  fault tolerance  FC (Fibre Channel)  FCoE (Fibre Channel over Ethernet)  first responder  full backup  HA (high availability)  hot site  HSRP (Hot Standby Routing Protocol)  IB (InfiniBand)  incident  incident response policies  incremental backup  iSCSI (Internet SCSI)  LACP (Link Aggregation Control Protocol)  link aggregation  load balancer  load balancing  loss-tolerant  managed object  MIB (Management Information Base)  MTBF (mean time between failures)  MTTR (mean time to repair)  NAS (network attached storage)  network management  NIC teaming  NMS (network management system) server  OID (object identifier)  packet analysis  packet drop  performance management  polling  port aggregation  QoS (quality of service)  redundancy  redundant power circuit  SAN (storage area network)  snapshot  syslog (system log)  traffic analysis  traffic policing  traffic shaping  UPS (uninterruptible power supply)  utilization  VIP (virtual IP address)  VRRP (Virtual Router Redundancy Protocol)  warm site Chapter 12 Wide Area Networks At a Glance Instructor’s Manual Table of Contents • Overview • Objectives • Teaching Tips • Quick Quizzes • Class Discussion Topics • Additional Projects • Additional Resources • Key Terms Lecture Notes Overview This chapter focuses on WANs (wide area networks), which are networks that connect two or more geographically distinct LANs. WANs are significant concerns for organizations attempting to meet the needs of telecommuting workers, global business partners, and Internet-based commerce. This chapter discusses WAN topologies and various technologies used by WANs. It also notes the potential pitfalls in establishing and maintaining WAN connections. Chapter Objectives After reading this chapter and completing the exercises, the student will be able to: • Identify the fundamental elements of WAN service options • Compare and contrast Layer 1 WAN technologies • Compare and contrast Layer 2 WAN technologies • Explain the most common wireless WAN technologies Teaching Tips WAN Essentials 1. Describe why any business or government institution with sites scattered over a wide geographical area needs a WAN. Provide examples. 2. Discuss the major characteristics of WANs including how a WAN differs from a LAN. 3. Define and explain the term NSPs (network service providers). 4. Define the term, dedicated line and explain the advantages it provides. Data Transfer Methods 1. Define and describe a WAN link. Use Figure 12-1 to illustrates the difference between WAN and LAN connectivity. 2. Use Figure 12-2 to discuss the difference between Data Terminal Equipment (DTE) and Data Communications Equipment (DCE). 3. Discuss the primary categories of WAN connections: a. dedicated line b. virtual circuit c. PVC (permanent virtual circuit) d. SVC (switched virtual circuit) 4. Explain to students that switching determines how connections are created between nodes on a network. 5. Discuss the differences between circuit-switched and packet-switched technologies. Point out that a LAN always uses packet-switched connections, but a WAN can use either. However, packet-switched connections are more common on WANs. 6. Use Table 12-1 to provide an overview of wired WAN technologies. Teaching Tip Students may read more about packet-switched vs. circuit-switched networks at https://www.buzzle.com/articles/packet-switched-vs-circuit-switched-networks.html Troubleshooting an Internet Connection 1. Explain the importance of understanding ISP equipment vs. equipment belonging to the subscriber (known as CPE or customer premise equipment). 2. Discuss the following equipment: a. NIU (network interface unit) b. line driver c. CSU/DSU 3. Discuss some common issue to look for on customer equipment: a. interface error b. DNS issues c. router misconfiguration d. interference Layer 1 WAN Technologies 1. Discuss examples of Layer 1 standards such as DSL, ISDN, SONET, T-carrier links. 2. Point out that a significant difference between the Layer 1 technologies is whether the connection is shared among many customers or dedicated to one customer. 3. Discuss the following: a. broadband b. DIA (dedicated internet access) PSTN (Public Switched Telephone Network) 1. Define and describe a PSTN. Mention that the name POTS also refers to a PSTN. 2. Note how PSTNs originally carried analog traffic and compare it to today’s methods. 3. Use Figure 12-6 to illustrate the local loop portion for dial-up WAN access. 4. Discuss the three examples of PSTN-based network technologies. Point out that these are mostly obsolete, but they are important building-blocks for understanding later technologies. 5. Briefly cover the Legacy Networking: Dial-Up section on page 691 of the text. 6. Briefly describe the history of ISDN. 7. Define and explain the two types of ISDN channels on which connections are based: a. B channels b. D channels 8. Describe a BRI (Basic Rate Interface). 9. Define the term bonding. 10. Use Figure 12-9 to illustrate a BRI link. 11. Describe a PRI (Primary Rate Interface). 12. Compare and contrast PRI and BRI connections. 13. Use Figure 12-10 to illustrate a PRI link. DSL (Digital Subscriber Line) 1. Define and describe characteristics of a DSL (digital subscriber line). 2. Define the term xDSL. Describe the better-known DSL varieties: a. ADSL (asymmetric DSL) b. VDSL (very high rate DSL or variable DSL) c. SDSL (symmetric DSL) d. 3. Explain the concepts of downstream and upstream data transmission. 4. Explain how an ADSL connection flows from a home computer, through the local loop, and to the telecommunications carriers switching facility. Use Figure 12-11 in your discussion. 5. Define the term DSL modem. 6. Use Figure 12-12 to illustrate a DSL modem. 7. Explain what a DSLAM (DSL access multiplexer) is and what it does. 8. Review DSL installation costs. Teaching Tip Students may find more information on DSL at http://computer.howstuffworks.com/dsl.htm Cable Broadband 1. Introduce broadband cable. Mention that it is also known as cable modem access. 2. Describe the transmission media used by broadband cable. 3. Compare the theoretical transmission rates with the real transmission rates. 4. Describe the infrastructure required for broadband cable to operate. Use Figure 12-13 to illustrate the infrastructure of a cable system. 5. Define a cable modem and explain its purpose in broadband communication. 6. Use Figure 12-14 to illustrate a cable modem. 7. Point out that broadband cable provides a dedicated, or continuous, connection that does not require dialing up a service provider. 8. Mention that cable broadband access continues to service the majority of residential customers, whereas DSL is more popular among business customers. Teaching Tip Students may find more information on cable modems at http://www.howstuffworks.com/cable-modem.htm Teaching Tip Students may find more information on cable technologies at http://docwiki.cisco.com/wiki/Cable_Access_Technologies Metro (Metropolitan Ethernet) 1. Discuss the growing trend of Metro Ethernet, also known as Carrier Ethernet. 2. Explain that Carrier-Ethernet Transport (CET) is an Ethernet-based transport solution designed to overcome the inherent weaknesses of implementing Ethernet outside of the LAN environment. 3. Use Figure 12-16 to discuss how CET predetermines a pathway and tags frames to follow the specified path. 4. Discuss the many advantages of Metro Ethernet, including: a) streamlined connections b) cost efficiency c) scalability d) familiarity e) hardware Quick Quiz 1 1. True or False: A WAN link is a connection between one WAN site and another site. Answer: True 2. What is a customer’s endpoint device on a WAN is called? Answer: DTE 3. True or False: PVCs are dedicated, individual links. Answer: False 4. True or False: Broadband cable relies on the PSTN for transmission medium. Answer: False 5. Which of the following types of communication occurs when the downstream throughput is higher than the upstream throughput? a. DSU b. CSU c. Symmetrical d. Asymmetrical Answer: D T-Carriers 1. Introduce T-carrier technology. Point out that T-carriers provide a dedicated logical circuit that is used by only one customer. 2. Describe the T-carrier transmission medium. 3. Discuss the different types of T-carrier lines: a. T1 b. T3 c. fractional T1 4. Use Table 12-3 to illustrate the various T-carrier specifications. 5. Describe a T1 circuit’s operation and throughput. 6. Describe a T3 circuit’s operation and throughput. 7. Describe common uses for T1 and T3 lines. 8. Define a fractional T1 lease and its advantages. 9. Explain that T1s are often used to support voice services. Discuss the two primary ways it does this: a. ISDN PRI or T1 PRI b. SIP trunking 10. Introduce characteristics of T-carrier connectivity hardware used at both the customer site and the local telecommunications providers switching facility. 11. Define and explain the functions of a smart jack. 12. Use Figure 12-18 to illustrate a T1 smart jack. 13. Define and explain the functions of CSUs (channel service units) and DSUs (data service units). 14. Use Figure 12-19 to illustrate a stand-alone CSU/DSU. 15. Explain that a multiplexer combines multiple signals from a LAN for transport over the T-carrier line and separates incoming T-carrier line’s combined channels into individual signals that can be interpreted on the LAN. 16. Use Figure 12-20 to illustrate how a router with an integrated CSU/DSU can be used to connect a LAN with a T1 WAN link. SONET (Synchronous Optical Network) 1. Describe the four key strengths of SONET. 2. Explain the interoperability advantage of SONET. 3. Point out that SONET is known internationally as SDH (Synchronous Digital Hierarchy). 4. Explain that SONET is not usually used as a last mile service. Instead, it often traverses multiple ISP networks, connecting them through the Internet backbone. 5. Use Figure 12-21 to discuss SONET tributaries and transmission. 7. Mention that SONET frames are sent out on a regular schedule and that their frames are a consistent size. Use Figure 12-22 to review the construction of a SONET frame. 8. Define the term OC (Optical Carrier) level and explain its relation in determining the data rate of a particular SONET ring. 9. Use Table 12-4 to list the OC levels and their maximum throughput. 10. Explain the best use of SONET. Teaching Tip Students may find a tutorial on SONET at http://compnetworking.about.com/od/hardwarenetworkgear/l/aa092800a.htm Layer 2 WAN Technologies 1. Explain that there are some Layer 2 technologies that traverse the ISP’s network in order to connect two or more LANs across a WAN connection. Frame Relay 1. Define and describe frame relay. Point out that frame relay can be used as the Data Link layer protocol for various virtual circuit interfaces and media. 2. Explain why frame relay is considered a connection-oriented protocol. 3. Use Figure 12-23 to demonstrate three frame relay connections to an ISP that creates two logical PVCs. 4. Define the term CIR (committed information rate). 5. Describe how the lease works for a PVC circuit. 6. Discuss frame relay lease advantages. Teaching Tip Students may find more information on frame relay at http://docwiki.cisco.com/wiki/Frame_Relay ATM (Asynchronous Transfer Mode) 1. Point out where ATM protocols operate in the OSI model. 2. Explain that with ATM, asynchronous refers to a communications method in which nodes do not have to conform to any predetermined schemes that specify the timing of data transmissions. 3. Point out that like Ethernet and frame relay, ATM specifies Data Link layer framing techniques. 4. Explain what sets ATM apart from Ethernet on a LAN and frame relay on a WAN. 5. Explain that in ATM, a packet is called a cell and the cell always consists of 48 bytes of data plus a 5-byte header. 6. Describe a drawback of a smaller packet size and explain how the drawback is overcome by cell efficiency. 7. Explain how ATM relies on virtual circuits. Point out that the use of virtual circuits makes ATM a connection-oriented technology. 8. Explain how ATM guarantees specific QoS (quality of service). 9. Point out the cost disadvantage inherent with ATM. Teaching Tip Students may find a tutorial on ATM at http://www.radio-electronics.com/info/telecommunications_networks/asynchronous-transfer-mode/atm-basics-tutorial.php MPLS (Multiprotocol Label Switching) 1. Use Figure 12-25 to discuss MPLS and how an ISP might use an MPLS WAN to move traffic from one customer site to another. 2. Discuss the formation of an MPLS shim within a frame. Use Figure 12-26 in your discussion. Wireless WANs 1. Introduce and describe wireless WANs. Point out that wireless WANs are designed for high-throughput, long-distance digital data exchange. Teaching Tip To learn more about wireless WAN technologies, students may visit: http://etutorials.org/Networking/wn/Chapter+7.+Wireless+WANs+Networks+for+Worldwide+Connections/Wireless+WAN+Technologies/ Cellular 1. Define and describe cellular networks. 2. Describe the performance characteristics of each generation of cellular technology. 3. Discuss the two competing voice technologies: a) GSM b) CDMA 4. Explain the architecture of cellular networks using Figure 12-27. 5. Explain that in order to qualify for the CompTIA Network+ certification, students will need to understand the basic infrastructure of the following cellular networks: a) HSPA+ b) LTE Satellite 1. Introduce satellite Internet access by explaining where it is best utilized. 2. Define and describe geosynchronous earth orbit (GEO). 3. Use Figure 12-28 to illustrate satellite communication. 4. Note that geosynchronous orbiting satellites are the most popular for satellite Internet access. 5. Describe satellite frequencies. 6. Use Table 12-5 is discuss satellite frequency bands. 7. Point out that satellite services are typically asymmetrical and bandwidth is shared among many subscribers Discuss they typical downlink and uplink rates that can be expected. 8. Discuss the drawbacks of satellite services. Quick Quiz 2 1. Which of the following is used to convert T-Carrier frames into frames the LAN can interpret and vice versa? a. smart jack b. CSU c. DSU d. terminal adapter Answer: C 2. True or False: An advantage of leasing a dedicated service over leasing a frame relay circuit is that you pay for only the amount of bandwidth required. Answer: False 3. Which of the following attributes sets ATM apart from Ethernet and Frame Relay? e. Fixed packet size f. Security g. Wiring h. Throughput Answer: A 4. True or False: An advantage of SONET is its fault tolerance. Answer: True 5. ____ orbiting satellites are the type used by the most popular satellite data service providers. Answer: Geosynchronous Class Discussion Topics 1. Take a class poll to determine what kind of Internet access students have at home. Discuss the availability of DSL in the area, and the pros and cons of each available access type. 2. Discuss the security implication of always-on technologies like DSL in remote home offices. What concerns are there? Are they justified? Is the technology worth the security risks, if any? Additional Projects 1. Have students compare cable broadband and DSL services in their residential areas. Each student should write a report summarizing his or her findings. 2. Have students research satellite Internet access. Students may select a vendor supplying the service, a manufacturer, or a technology. Each student should write a report summarizing his or her findings. Additional Resources 1. Local Loop http://searchnetworking.techtarget.com/definition/local-loop 2. DSL resource http://www.dslreports.com/ 3. What is Broadband? https://whatismyipaddress.com/broadband 4. Cable Networks http://en.wikibooks.org/wiki/Communication_Networks/Cable 5. Cellular Networks http://www.techopedia.com/definition/24962/cellular-network Key Terms For definitions of key terms, see the Glossary near the end of the book.  4G  ADSL (asymmetric DSL)  asymmetrical  asynchronous  ATM (Asynchronous Transfer Mode)  B channel  bandwidth speed tester  BRI (Basic Rate Interface)  broadband  cable broadband  cable modem  Carrier Ethernet  CDMA (Code Division Multiple Access)  cell  CET (Carrier-Ethernet Transport)  circuit-switched  CSU/DSU  D channel  dedicated line  DIA (dedicated Internet access)  dial-up  DOCSIS (Data Over Cable Service Interface Specifications)  DSL (digital subscriber line)  E1  E3  fractional T1  frame relay  GSM (Global System for Mobile Communications)  HFC (hybrid fiber coaxial)  HSPA+ (High Speed Packet Access Plus)  ISDN (Integrated Services Digital Network)  local loop  LTE (Long-Term Evolution)  LTE-Advanced  Metro (Metropolitan) Ethernet  modem  MPLS (multiprotocol label switching)  NIU (network interface unit)  OC (Optical Carrier)  OC-1  OC-3  OC-12  packet-switched  PRI (Primary Rate Interface)  PSTN (public switched telephone network)  PVC (permanent virtual circuit)  SDH (Synchronous Digital Hierarchy)  SDSL (symmetric DSL)  SIM (Subscriber Identity Module) card  SIP trunking  smart jack  SONET (Synchronous Optical Network)  SVC (switched virtual circuit)  switching  symmetrical  synchronous  T1  T3  T-carrier  TDMA (time division multiple access)  VDSL (very high bit rate DSL or variable DSL)  virtual circuit  xDSL (extended DSL) Instructor Manual for Network+ Guide to Networks Jill West, Tamara Dean, Jean Andrews 9781337569330, 9781133608196