Chapter 15 - Review

Network+ Guide to Networks, Chapter 15 Review

Network Management

In this book, you have learned the technologies and techniques necessary to design an efficient, fault-tolerant, and secure network. However, your work isn’t finished once all the clients, servers, switches, routers, and gateways have been installed. After a network is in place, it requires continual review and adjustment. A network, like any other complex system, is in a constant state of flux. Whether the changes are caused by internal factors, such as increased demand on the server’s processor, or external factors, such as the obsolescence of a router, you should count on spending a significant amount of time investigating, performing, and verifying changes to your network. In this chapter, you will learn about changes dictated by immediate needs as well as those required to enhance the network’s functionality, growth, performance, or security. You’ll also learn how best to implement those changes.

Fundamentals of Network Management

Network management is a general term that means different things to different networking professionals. At its broadest, network management refers to the assessment, monitoring, and maintenance of all aspects of a network. It can include checking for hardware faults, ensuring high QoS (quality of service) for critical applications, maintaining records of network assets and software configurations, and determining what time of day is best for upgrading a router. The scope of network management techniques differs according to the network’s size and importance. On some large networks, for example, administrators run network management applications that continually check devices and connections to make certain they respond within an expected performance threshold. If a device doesn’t respond quickly enough or at all, the application automatically issues an alert that pages the network administrator responsible for that device. On a small network, however, comprehensive network management might not be economically feasible. Instead, such a network might run an inexpensive application that periodically tests devices and connections to determine only whether they are still functioning. Several disciplines fall under the heading of network management, including topics discussed in previous chapters, such as posture assessments. All share the goals of enhancing efficiency and performance while preventing costly downtime or loss. Ideally, network management accomplishes this by helping the administrator predict problems before they occur. For example, a trend in network usage could indicate when a switch will be overwhelmed with traffic. In response, the network administrator could increase the switch’s processing capabilities or replace the switch before users begin experiencing slow or dropped connections. Before you can assess and make predictions about a network’s health, however, you must first understand its logical and physical structure and how it functions under typical conditions.

Documentation

Throughout this book, you have witnessed and read about different types of network documentation. For example, in Chapter 13’s discussion of troubleshooting, you learned that keeping a record of a problem and its solution helps to prevent similar problems from recurring, or at least helps technicians deal with it if it does recur. In this section and in the rest of this chapter, you’ll learn about other types of documentation that contribute to sound network management.

The way you format and store your documentation can vary, but to adequately manage your network, you should at least record the following:

Physical topology—Which types of LAN and WAN topologies does your network use: bus, star, ring, hybrid, mesh, or a combination of these? Which type of backbone does your network use—collapsed, distributed, parallel, serial, or a combination of these? Which type and grade of cabling does your network use? What types of cables are used and where are they located?

Access method—Does your network use Ethernet (802.3), Wi-Fi (802.11), WiMAX (802.16), cellular, satellite, or a mix of transmission methods? What transmission speed(s) does it provide? Is it switched?

Protocols—Which protocols are used by servers, nodes, and connectivity devices?

Devices—How many of the following devices are connected to your network—switches, routers, gateways, firewalls, access points, servers, UPSs, printers, backup devices, and clients? Where are they located? Are they physical or virtual? If physical, what are their model numbers and vendors?

Operating systems—Which network and desktop operating systems appear on the network? Which versions of these operating systems are used by each device? Which type and version of operating systems are used by connectivity devices such as routers?

Applications—Which applications are used by clients and servers? Where do you store the applications? From where do they run?

Configurations—What versions of operating systems and applications does each workstation, server, and connectivity device run? How are these programs configured? How is hardware configured? The collection, storage, and assessment of such information belong to a category of network management known as configuration management. Ideally, you would rely on configuration management software to gather and store the information in a database, where those who need it can easily access and analyze the data.

If you have not already collected and centrally stored the answers to the s just listed, it could take the efforts of several people and several weeks to compile them, depending on the size and complexity of your network. This evaluation involves visits to the telecommunications and equipment rooms, an examination of servers and desktops, a review of receipts for software and hardware purchases, and, potentially, the use of a protocol analyzer or network management software package. Though it requires effort, documenting all aspects of your network promises to save work in the future. After you have compiled the information, organize it into a database that can be easily updated and searched. That way, staff can access the information in a timely manner and keep it current. Understanding conventions for network documentation can make your task easier.

In this book, you have seen many instances of network diagrams, which are graphical representations of a network’s devices and connections. Network diagrams can be as varied as the engineers who create them. Some adhere strictly to the network’s physical layout and label each connection. Some represent only the logical topology. Others, like many of the figures in this book, are more general or designed to highlight one critical part of a network, such as its perimeter. These might depict an internal network of hundreds of clients with only a few clients within a circle labeled “internal network,” for example. You could sketch your network diagram on the back of a napkin or draw it on your computer using a graphics program. However, many people use software designed for mapping networks, such as Dia, Edraw, Gliffy, Microsoft Visio, or Network Notepad. Such applications come with icons that represent different types of devices and connections. Soon after entering the world of network engineering, you’ll recognize certain icons that Cisco Systems has created and made popular. Because of its status in the networking world and the volume of networking hardware it sells, Cisco has set trends for network diagramming. Like the “Walk” or “Don’t Walk” signs that are understood on street corners around the globe, Cisco’s symbols for routers, switches, firewalls, and other devices are widely accepted and understood in the networking field. Figure 15-1 shows a simplified network diagram that uses Cisco’s iconography, with each device labeled. Notice that a router is represented by a hockey-puck shape with two arrows pointing inward and two arrows pointing outward. A wireless router looks the same, but has two antennas attached. A workgroup switch is represented by a small rectangular box, which also contains two arrows pointing inward and two arrows pointing outward. Most network diagrams provide broad snapshots of a network’s physical or logical topology. This type of view is useful for planning where to insert a new switch or determining how a particular router, gateway, and firewall interact. However, if you’re a technician who needs to find a fault in a client’s wired connection to the LAN, a broad overview might be too general. Instead, you need a wiring schematic. A wiring schematic is a graphical representation of a network’s wired infrastructure. In its most detailed form, it shows every wire necessary to interconnect network devices. Some less-detailed wiring schematics might use a single line to represent the group of wires necessary to connect several clients to a switch. Figure 15-2 provides an example of a detailed wiring schematic for a small office network connection that relies on cable broadband service to access the Internet. Documenting and capturing an accurate picture of your network’s physical and logical elements are initial steps in understanding the network. Next you need to know how it routinely performs.

Baseline Measurements

As you learned in Chapter 13, a baseline is a report of the network’s current state of operation. Baseline measurements might include the utilization rate for your network backbone, number of users logged on per day or per hour, number of protocols that run on your network, statistics about errors (such as runts, collisions, jabbers, or giants), frequency with which networked applications are used, or information regarding which users take up the most bandwidth. The graph in Figure 15-3 shows a sample baseline for daily network traffic over a six-week period. Baseline measurements allow you to compare future performance increases or decreases caused by network changes or events with past network performance. Obtaining baseline measurements is the only way to know for certain whether a pattern of usage has changed (and requires attention) or, later, whether a network upgrade made a difference. Each network requires its own approach. The elements you measure depend on which functions are most critical to your network and its users. For instance, suppose that your network currently serves 500 users and that your backbone traffic exceeds 50% at 10:00 a.m. and 2:00 p.m. each business day. That pattern constitutes your baseline. Now suppose that your company decides to add 200 users who perform the same types of functions on the network.

The added number of users equals 40% of the current number of users (200/500). Therefore, you can estimate that your backbone’s capacity should increase by approximately 40% to maintain your current service levels. The more data you gather while establishing your network’s baseline, the more accurate your prediction will be. Network traffic patterns might be difficult to forecast because you cannot predict users’ habits, effects of new technology, or changes in demand for resources over a given period of time. For instance, the preceding example assumed that all new users would share the same network usage habits as the current users. In fact, however, the new users may generate a great deal more, or a great deal less, network traffic. How do you gather baseline data on your network? Although you could theoretically use a network monitor or network analyzer and record its output at regular intervals, several software applications can perform the baselining for you. These applications range from freeware available on the Internet to expensive, customizable hardware and software combination products. Before choosing a network-baselining tool, you should determine how you will use it. If you manage a small network that provides only one critical application to users, an inexpensive tool may suffice. If you work on a WAN with several critical links, however, you should investigate purchasing a more comprehensive package. The baseline measurement tool should also be capable of collecting the statistics needed. For example, only a sophisticated tool can measure traffic generated by each node on a network, filter traffic according to types of protocols and errors, and simultaneously measure statistics from several different network segments.

Policies, Procedures, and Regulations

Imagine you are the network administrator for a large enterprise network and that you supervise eight network technicians who are responsible for day-to-day installations, upgrades, and troubleshooting. Unless you and your technicians agree on policies for adding new users, for example, you might discover that some users have fewer access restrictions than they ought to have or that logon IDs don’t follow a standard naming convention. The former could cause security vulnerabilities, and the latter could make future user management more challenging. Following rules helps limit chaos, confusion, and possibly downtime for you and your users. Previous chapters of this book have described policies, procedures, and regulations that make for sound network management. They are summarized here:

Media installation and management—Includes designing the physical layout of a cable or wireless infrastructure, choosing and following best practices for cable management, testing the effectiveness of cable or wireless infrastructure, and documenting cable layouts; see Chapters 3 and 8 for more information.

Network addressing policies—Includes choosing and applying an addressing scheme, determining the use and limits of subnets, integrating an internal network’s addressing with an external network’s, and configuring gateways for NAT; see Chapters 4 and 9 for more information.

Security-related policies—Includes establishing rules for passwords, limiting access to physical spaces such as the data center, limiting access to shared resources on the network, imposing restrictions on the types of files that are saved to networked computers, monitoring computers for malware, and conducting regular security audits; see Chapters 11 and 14 for more information.

Troubleshooting procedures—Includes following a methodology for troubleshooting network problems and documenting their solutions; see Chapter 13 for more information.

Backup and disaster recovery procedures—Includes establishing a method and schedule for making backups, regularly testing the effectiveness of backups, assigning a disaster recovery team and defining each member’s role, and choosing a disaster recovery strategy and testing it; see Chapter 14 for more information.

In addition to internal policies, a network manager must consider state and federal regulations that might affect her responsibilities. In the United States, one such federal regulation is CALEA (Communications Assistance for Law Enforcement Act), which requires telecommunications carriers and equipment manufacturers to provide for surveillance capabilities. CALEA was passed by Congress in 1994 after pressure from the FBI, which worried that networks relying solely on digital communications would circumvent traditional wiretapping strategies. In other words, a phone call made using VoIP over a private WAN cannot be intercepted as easily as a phone call made via the PSTN. Therefore, if you work at an ISP, for example, your switches and routers must provide an interface for electronic eavesdropping and your staff must be ready to allow authorities access to those devices when presented with a warrant. A second significant federal regulation in the United States is HIPAA (Health Insurance Portability and Accountability Act), which was passed by Congress in 1996. One aspect of this regulation addresses the security and privacy of medical records, including those stored or transmitted electronically. If you work at any organization that handles medical records, such as an insurance company, hospital, or transcription service, you must understand and follow federal standards for protecting the security and privacy of these records. HIPAA rules are very specific. They govern not only the way medical records are stored and transmitted, but also the policies for authorizing access and even the placement and orientation of workstations where such records might be viewed. Many of the policies and procedures mentioned in this section are not laws, but best practices aimed at preventing network problems before they occur. The next section describes techniques for detecting and managing network problems before they significantly impair access or performance.

Fault and Performance Management

After documenting every aspect of your network and following policies and best practices, you are ready to assess your network’s status on an ongoing basis. This process includes both performance management and monitoring how well links and devices are keeping up with the demands placed on them, and fault management, or the detection and signaling of device, link, or component faults.

Network Management Systems

To accomplish both fault and performance management, organizations often use enterprise-wide network management systems. Hundreds of such tools exist. All rely on a similar architecture, in which at least one network management console, which may be a server or workstation, depending on the size of the network, collects data from multiple networked devices at regular intervals, in a process called polling. Each managed device runs a network management agent, a software routine that collects information about the device’s operation and provides it to the network management application running on the console. So as not to affect the performance of a device while collecting information, agents do not demand significant processing resources. A managed device may contain several objects that can be managed, including components such as processor, memory, hard disk, NIC, or intangibles such as performance or utilization.

For example, on a server, an agent can measure how many users are connected to the server or what percentage of the processor’s resources are used at any time. The definition of managed devices and their data are collected in a MIB (Management Information Base). Agents communicate information about managed devices via any one of several Application layer protocols. On modern networks, most agents use SNMP (Simple Network Management Protocol). SNMP is part of the TCP/IP suite of protocols and typically runs over UDP on port 161 (though it can be configured to run over TCP). Three versions of SNMP exist: SNMPv1, SNMPv2, and SNMPv3. SNMPv1 (Simple Network Management Protocol version 1) was the original version, released in 1988. Because of its limited features, it is rarely used on modern networks. SNMPv2 (Simple Network Management Protocol version 2) improved on SNMPv1 with improved performance and slightly better security, among other features. SNMPv3 (Simple Network Management Protocol version 3) is similar to SNMPv2, but adds authentication, validation, and encryption for packets exchanged between managed devices and the network management console.

SNMPv3 is the most secure version of the protocol. However, some administrators have hesitated to upgrade to SNMPv3 because it requires more complex configuration. Therefore, SNMPv2 is still widely used. Most network management applications support multiple versions of SNMP. Some managed devices, however, support only one version. Figure 15-4 illustrates the relationship between a network management application and managed devices on a network. After data is collected, the network management application can present an administrator with several ways to view and analyze the data. For example, a popular way to view data is in the form of a map that shows fully functional links or devices in green, partially (or less than optimally) functioning links or devices in yellow and failed links or devices in red. An example of the type of map generated by a network performance monitor is shown in Figure 15-5. Because of their flexibility, sophisticated network management applications are also challenging to configure and fine-tune. You have to be careful to collect only useful data and not an excessive amount of routine information. For example, on a network with dozens of routers, collecting SNMP-generated messages that essentially say “I’m still here” every five seconds would result in massive amounts of insignificant data. A glut of information makes it difficult to ascertain when a router in fact requires attention. Instead, when configuring a network management application to poll a router, you might choose to generate an SNMP-based message only when the router’s processor is operating at 75% of its capacity or to measure only the amount of traffic passing through a NIC every five minutes. Faults and conditions that exceed certain thresholds can trigger alarms in network management software. They can also be recorded by system and event logs, as described next.

System and Event Logs

Virtually every condition recognized by an operating system can be recorded. Records of such activity are kept in a log. For example, each time your computer requests an IP address from the DHCP server and doesn’t receive a response, this can be recorded in a log. Likewise, a log entry can be added each time a firewall denies a host’s attempt to connect to another host on the network that the firewall defends. Different operating systems log different kinds of events by default. In addition, network administrators can customize logs by defining conditions under which new entries are created. For example, an engineer might want to know when the relative humidity in a data center exceeds 60%. If a device can monitor this information, the results can be written to a log. On Windows-based computers, such a log is known as an event log and can be easily viewed with the Event Viewer application. Figure 15-6 provides an example of data collected in the event log on a workstation running the Windows 7 operating system. In the Hands-On Projects at the end of this chapter, you will view an event log using Windows Event Viewer.

Similar information is routinely recorded by computers running Linux or UNIX via the syslog function. Syslog is a standard for generating, storing, and processing messages about events on a system. It describes methods for detecting and reporting events and specifies the format and contents of messages. It also defines roles for each computer that participates in logging events. For example, the computer that is monitored by a syslog-compatible application and that issues event information is known as a generator. The computer that gathers event messages from generators is known as a collector. The syslog standard also establishes levels of severity for every logged event. For example, “0” indicates an emergency situation and “7” simply points to very specific information that might help in debugging a problem. Computers running Linux and UNIX record syslog data in a system log. In general, newer versions of Linux typically write their system logs to the file /var/log/messages, while older versions of UNIX often write to a system log in the file /var/logs/syslog and Solaris versions of UNIX write to a system log in the file /var/adm/messages. To find out where various logs are kept on your UNIX or Linux system, view the /etc/syslog.conf file (on some systems this is the /etc/rsyslog.conf  file). The /etc/syslog.conf file is also where you can configure the types of events to log and what priority to assign each event. Bear in mind that the syslog function doesn’t alert you to any problems, but it does keep a history of messages issued by the system. It’s up to you to monitor the system log for errors. Most UNIX and Linux operating systems provide a GUI application for easily viewing and filtering the information in system logs. Other applications are available for sifting through syslog data and generating alerts. In the Hands-On Projects at the end of this chapter, you’ll view and sort through data in a system log. Much of the information collected in event logs and system logs does not point to a problem, even if it is marked with a warning. For example, you might have typed your password incorrectly while trying to log on to your computer, thus generating a log entry. Using these logs for fault management requires thoughtful data filtering and sorting.

Traffic Shaping

When a network must handle high volumes of network traffic, users benefit from a performance management technique known as traffic shaping. Traffic shaping involves manipulating certain characteristics of packets, data streams, or connections to manage the type and amount of traffic traversing a network or interface at any moment. Its goals are to assure timely delivery of the most important traffic while offering the best possible performance for all users. Traffic shaping can involve delaying less-important traffic, increasing the priority of more important traffic, limiting the volume of traffic flowing in or out of an interface during a specified time period, or limiting the momentary throughput rate for an interface. The last two techniques belong to a category of traffic shaping known as traffic policing. An ISP might impose a maximum on the capacity it will grant a certain customer. That way, it ensures that the customer does not tie up more than a certain amount of the network’s overall capacity. Traffic policing helps the service provider predict how much capacity it must purchase from its network provider. It also holds down costs because the ISP doesn’t have to plan for every client using all the throughput he could at all times (an unlikely scenario). An ISP that imposes traffic policing might allow customers to choose their preferred maximum daily traffic volume or momentary throughput and pay commensurate fees. A more sophisticated instance of traffic policing is dynamic and takes into account the network’s traffic patterns. For example, the service provider might allow certain customers to exceed their maximums when few other customers are using the network. Figure 15-7 illustrates how traffic volume might appear on an interface without limits compared with an interface subject to traffic policing. A controversial example of traffic shaping came to light in 2007. Comcast, one of the largest Internet service providers in the United States, was found to be clandestinely discriminating against certain types of traffic.

For users uploading files to P2P (peer-to-peer) networks such as BitTorrent, Comcast was interjecting TCP packets with the RST (reset) field set. These packets were spoofed to appear as if they originated from the accepting site, and they cut the connection as the user attempted to upload files. Soon customers figured out the pattern and used packet analyzers such as Wireshark to reveal the forged TCP RST packets. They complained to authorities that Comcast had violated their user agreement. The FCC investigated, upheld the customers’ claims, and ordered Comcast to stop this practice. Comcast chose a different method of traffic shaping. It assigned a lower priority to data from customers who generate a high volume of traffic when the network is at risk of congestion. Several types of traffic prioritization—that is, treating more-important traffic preferentially— exist. Software running on a router, multilayer switch, gateway, server, or even a client workstation can prioritize traffic according to any of the following characteristics:

·         Protocol

·         IP address

·         User group

·         DiffServ (Differentiated Services) flag or TOS (type of service) field in an IP datagram

·         VLAN tag in a Data Link layer frame

·         Service or application

Depending on the traffic prioritization software, different types of traffic might be assigned priority classes, such as “high,”“normal,”“low,” or “slow;” alternatively, it can be rated on a prioritization scale from 1 (lowest priority) to 7 (highest priority). For example, traffic generated by time-sensitive VoIP applications might be assigned high priority, while online gaming might be assigned low priority. Traffic prioritization is needed most when the network is busiest. It ensures that during peak usage times, the most important data get through quickly, while less-important data waits. When network usage is low, however, prioritization might have no noticeable effects.

Caching

In addition to traffic shaping, a network or host might use caching to improve performance.

Caching is the local storage of frequently needed files that would otherwise be obtained from an external source. By keeping files close to the requester, caching allows the user to access those files quickly. As you’ll learn, it can also save money for ISPs. The most common type of caching is Web caching, in which Web pages are stored locally, either on a host or network, and then delivered to requesters. You might be familiar with the term cache from browsing the Web on your computer. A locally stored cache will keep copies of the Web pages you have viewed on your computer’s hard drive. Later, when you want to view the page again, the browser will attempt to retrieve the page from your cache if the page hasn’t changed since the last time you viewed it. Local caching is highly customizable. You can choose the size of your cache, the rules it uses to refresh its contents, and the conditions under which it clears its contents. To an ISP, however, caching is much more than just a convenience. It prevents a significant volume of WAN traffic, thus improving performance and saving money. For example, if dozens of an ISP’s subscribers read a popular news Web site each morning, the ISP can keep the entire Web site on its cache engine, a network device devoted to storage and delivery of frequently requested files. When the ISP’s network receives a request for that Web site, the network examines the request and redirects it to a cache engine. The cache engine searches its files for the news Web site. If the cache engine doesn’t have a current copy of the Web site, it requests the site from the news organization’s server. In that case, the cache engine receives and stores the Web site for later delivery.

When another user subsequently requests the same site, the network redirects the request to the cache engine, which delivers the Web site without having to request it from the originating server. The ISP need not spend any of its bandwidth to retrieve the site again until it has changed.

Asset Management

Another key component in managing networks is identifying and tracking its hardware and software through asset management. The first step in asset management is to take an inventory of each node on the network. This inventory should include the total number of components on the network, and also each device’s configuration files, model number, serial number, location on the network, and technical support contact. You will also want to keep records of every piece of software purchased by your organization, its version number, vendor, licensing, and technical support contact. The asset management tool you choose depends on your organization’s needs. You might purchase an application that can automatically discover all devices on the network and then save that information in a database, or you might use a simple spreadsheet to save the data. In either case, your asset management records should be comprehensive and accessible to all personnel who may become involved in maintaining or troubleshooting the network. In addition, ensure that the asset management database is regularly updated, either manually or automatically, as changes to network hardware and software occur. The information you retain is useful only while it is current. Asset management simplifies maintaining and upgrading the network chiefly because you know what the system includes. For example, if you discover that a router purchased two years ago requires an upgrade to its operating system software to fix a security flaw, you need to know how many routers are installed, where they are installed, and whether any have already received the software upgrade. An up-to-date asset management system allows you to avoid searching through old invoices and troubleshooting records to answer these. In addition, asset management provides network administrators with information about the costs and benefits of certain types of hardware or software. For example, if you conclude that 50% of your staff’s troubleshooting time is spent on one flawed brand of NIC, an asset management system can reveal how many NICs you would need to replace if you chose to replace those cards, and whether it would make sense to replace the entire installed base. Some asset management applications can even track the length of equipment leases and alert network managers when leases will expire.

Change Management

The term asset management originally referred to an organization’s system for keeping tabs on every piece of equipment it owned. This function was usually handled through the Accounting Department. Some of the accounting-related tasks included under the original definition for asset management, such as managing the depreciation on network equipment or tracking the expiration of leases, apply to asset management in networking as well.

Network conditions are always in a state of flux. Technology advances, vendors come and go, and users’ needs change. Managing change while maintaining your network’s efficiency and availability requires good planning. The following sections describe how to approach the most common types of software and hardware changes, from installing patches to replacing a network backbone.

Software Changes

If you have ever supported desktop computers professionally or even maintained your own computer at home, you know that an important part of keeping a system running optimally is upgrading its software. The following sections describe best practices for applying patches, application upgrades, and NOS upgrades.

Application Patches and Upgrades

A patch is a correction, improvement, or enhancement to a software application. It differs from a revision or software upgrade in that it changes only part of an application, leaving most of the code untouched. Patches are often distributed at no charge by software vendors in an attempt to fix a bug in their code or to add slightly more functionality. You’ll encounter patches in all areas of routine networking maintenance. Among other things, network maintenance sometimes entails patching the server’s operating system. For example, if your server runs Windows Server 2008 R2, you might need to apply a patch to close a security hole that allows remote users to hack into your server. Or you might have to patch the software on your Cisco switch to fix a vulnerability that makes it susceptible to denial-of-service attacks. A software upgrade is a major change to a software package’s existing code. Vendors might or might not offer upgrades for free. Also, the upgrade might or might not be comprehensive enough to substitute for the original application. In general, application upgrades are designed to add functionality and fix bugs in the previous version of the client. For example, an upgrade to a newer version of Google Chrome might incorporate features to protect you from Web sites that launch phishing attempts. The scope and purpose of client upgrades vary widely, depending on whether the upgrade is a redesign or simply a bug fix. An application upgrade might be transparent to users, or it might completely change the appearance of the application interface. Application upgrades typically overwrite some system files on the workstation, so their installation may affect other applications adversely. They might even prevent other applications from working as they did in the past. Whereas patches are usually designed to correct a problem or vulnerability, upgrades are usually designed to enhance the application’s functionality. For this reason, an application upgrade may be more a matter of convenience than necessity. Therefore, the time, cost, and effort involved in application upgrades should be weighed against the necessity of performing operating system or client upgrades. This consideration is especially important if a networking professional’s time is limited (as it usually is).

Although the specifics vary for each type of software change, the general steps involved can be summarized as follows:

1. Determine whether the patch or upgrade is necessary.

2. Research the purpose of the change, its compatibility with current hardware and software, and its potential effects on other applications. If possible, install the software on

a test system to make sure it acts as expected. Also determine whether and how the change can be reversed, in case troubles arise.

3. Determine whether the change should apply to some or all users. Also decide whether it will be distributed centrally or machine by machine.

4. After choosing to implement the change, notify system administrators, help desk personnel, and users. Schedule the change for completion during off-hours (unless it is an emergency).

5. Back up the current system or software before making any modifications.

6. If necessary, prevent users from accessing the system or the part of the system being altered during the change.

7. Keep the software vendor’s patch or upgrade instructions handy and follow them as you install the patch or revision.

8. Implement the change.

9. Test the system fully after the change, preferably exercising the software as a typical user would. Note any unintended or unanticipated consequences of the modification.

10. If the change was successful, reenable access to the system. If it was unsuccessful, revert to the previous version of the software following the process for reversing a software upgrade described later in this chapter.

11. Inform system administrators, help desk personnel, and users when the change is complete. If you had to reverse it, make this known and explain why.

12. Record your change in the change management system.

NOS (Network Operating System) Upgrades

Perhaps the most critical type of software upgrade you’ll perform is an upgrade to your NOS (network operating system). It usually involves significant, potentially drastic, changes to the way your servers and clients operate. As such, it requires plenty of forethought, product research, and rigorous testing before you implement it. In fact, for any network with more than a few users, you should create and follow project plan for this undertaking. This plan should include all of the precautions typically associated with other software upgrades. In addition, you should consider the following:

·         How will the upgrade affect user IDs, groups, rights, and policies?

·         How will the upgrade affect file, printer, and directory access on the server?

·         How will the upgrade affect applications or client interactions on the server?

·         How will the upgrade affect configuration files, protocols, and services running on the server?

·         How will the upgrade affect the server’s interaction with other devices on the network?

·         How accurately can you test the upgrade software in a simulated environment?

·         How can you take advantage of the new operating system to make your system more efficient?

·         What is your technical support arrangement with the operating system’s manufacturer if you need help in the midst of the upgrade?

·         Have you allotted enough time to perform the upgrade? (For example, would it be more appropriate to do it over a weekend rather than overnight?)

·         During the upgrade, will old NOS files be saved, and can you reverse the installation if troubles arise?

·         Have you ensured that the users, help desk personnel, and system administrators understand how the upgrade will affect their daily operations and support burdens?

These are only some of the critical s you need to ask before embarking on an NOS upgrade. Your networking environment might warrant additional considerations. For example, suppose you are the network administrator for a company that is merging with a second company. Your two companies might use dissimilar NOSs, and the IT director might ask you to upgrade your NOS to match the other company’s version. In this situation, you would not only have to consider the previous list of s, but also a list of s pertaining to the other company’s operating system—for instance, how its NOS directories are organized. By addressing these s before you upgrade your own NOS, you ensure that the merger of the two networks goes more smoothly. An NOS upgrade is a complex and far-reaching change. It should not be undertaken with severe budgetary, resource, or time constraints. The following steps demonstrate how careful planning and a methodical process can help you accomplish an NOS upgrade. (Depending on your situation, the order and complexity of the steps could vary.)

1. Research—Gather information about the NOS from the manufacturer and from other sources, including online user groups, reputable journals, and other networking professionals. Evaluate the costs involved in upgrading. Also list the benefits and risks involved in embarking on this NOS upgrade.

2. Project plan—Before you have committed significant time and money to the project, devise a project plan. This plan should include the steps to follow, task assignments for staff, and a rough budget and timeline. Even if you decide not to upgrade the NOS after all, you must commit resources to proposing and evaluating the option.

3. Proposal—Write a proposal to evaluate the product, including a plan to purchase and implement it if the proposal is accepted. A proposal should include the following elements:

·         s to answer during evaluation, such as “Will the NOS work with my current network monitoring software?”

·         Names of personnel who will assist with evaluation and final approval

·         A rough timeline and plan for implementing the change if it is approved

·         A rough project plan for implementing the change if it is approved

·         Cost considerations

·         A review of the short- and long-term benefits and risks of the upgrade

·         A recommendation for or against performing the upgrade

·         A plan for purchasing the software and implementing the change

4. Evaluation—Assuming that the proposal indicates that you should proceed with an upgrade and that your superiors approve your recommendation, you are ready to begin the evaluation phase. First order an evaluation copy of the NOS. Then install the software on an unused server whose hardware is similar to the hardware of your production servers (making sure that the test server meets the NOS manufacturer’s recommended hardware requirements). On the test system, create several mock user IDs and groups with varying privileges to simulate the real network environment. Also install the applications and services that the server will support if it goes into production.

5. Testing—Next, as part of your evaluation, distribute updated client software to a team of technical staff and project stakeholders and ask them to use the mock IDs and groups to test the system. Over a given time period, they can test the system and keep notes on how the system meets the requirements specified in your proposal. The test team should pay particular attention to the new user interface for clients, the way in which your company’s applications operate the system’s response time, and any new features provided by the upgrade. Meet regularly with the team during the evaluation period to discuss and compare experiences.

6. Training—If the results of the initial stages of evaluation lead you to decide to purchase the upgrade, make sure you and other networking staff are trained on how to work with the new NOS. Schedule training to take place only weeks before the anticipated implementation date so that your new skills are fresh when you begin the conversion.

7. Preimplementation—Before implementing the change, expand on the rough project plan for the upgrade. Ensure that your plan for transferring user accounts, groups, and their rights to the new system is sound. Decide how you want to reorganize the NOS directory, if necessary, and what types of volumes to create. In addition, review the existing servers to determine which applications, files, and directories should be transferred and which can be archived.

Weeks before upgrading, inform users, help desk personnel, and other networking staff of the timeline and explain what changes to expect. Recommend that users clean up their data directories on the server and discard any unnecessary files. Similarly, ask networking staff to remove any nonessential applications or services they have installed on the server. If necessary, arrange to upgrade the client software on all workstations that will be affected by the operating system upgrade. A few days before the upgrade, issue a final warning to staff specifying when and for how long the server will be down to accomplish the upgrade.

8. Implementation—Perform the upgrade when few or no users will be on the network. Before beginning the upgrade, gather the software documentation and your project plan, along with the new NOS files and a bootable disk for the server. Just before taking the system down, broadcast a final warning to alert all users on the network that the server is going down soon. Then disable all logons to the network. Next, back up the entire server’s hard disk. When the backup is complete, use your backup software to verify that critical files were successfully copied. Finally, perform the upgrade according to the manufacturer’s instructions and your network’s specifications.

9. Postimplementation—Test functions and applications on the upgraded server to verify the success of your upgrade. After you are satisfied that the upgrade is successful, reenable logons to the network and inform staff that the system is running again. Later, you can review the upgrade process with other networking staff to find out whether you learned any lessons that could make future server upgrades more efficient and less troublesome. Work with the help desk personnel to understand the kinds of support calls generated by the upgrade. Also continue testing the new operating system, fine-tuning when necessary, to fix problems or find errors before they become problems for users.

Reversing a Software Upgrade

If the software upgrade you perform creates problems in your existing system, you should be prepared to reverse the process. The process of reverting to a previous version of software after attempting to upgrade it is known as backleveling. Most network professionals have been forced to backlevel at some point in their careers. The steps that constitute this process differ, depending on the complexity of the upgrade and the network environment involved. Although no hard-and-fast rules for backleveling exist, Table 15-1 summarizes some basic suggestions. Bear in mind that you must always refer to the software vendor’s documentation to reverse an upgrade. If you must backlevel a network operating system upgrade, you should also consult with experienced professionals about the best approach for your network environment.

Table 15-1 Reversing a software upgrade

Type of upgrade	Options for reversing
Operating system patch	Use the patch’s automatic uninstall utility.
Client software upgrade	Use the upgrade’s automatic uninstall utility, or reinstall the previous version of the client on top of the upgrade.
Shared application upgrade	Use the application’s automatic uninstall utility, or maintain a complete copy of the previous installation of the application and reinstall it over the upgrade.
Operating system upgrade	Prior to the upgrade, make a complete backup of the system; to backlevel, restore the entire system from the backup; uninstall an operating system upgrade only as a last resort.

Hardware and Physical Plant Changes

Hardware and physical plant changes might be required when a network component fails or malfunctions, but more often they are performed as part of an upgrade to increase capacity, improve performance, or add functionality to the network. In this section, you will learn about the simplest and most popular form of hardware change—adding more of what you already use, such as adding four more switches to the backbone or adding 10 new networked printers. You’ll also learn about more complex hardware changes, such as replacing the entire network backbone with a more robust system. Many of the same issues apply to hardware changes as apply to software changes. In particular, proper planning is the key to a successful upgrade. When considering a change to your network hardware, use the following steps as a guide:

1. Determine whether the change is necessary.

2. Research the upgrade’s potential effects on other devices, functions, and users.

3. If you decide to implement the change, notify system administrators, help desk personnel, and users, and schedule it during off-hours (unless it is an emergency).

4. If possible, back up the current hardware’s configuration. Ideally, you would have stored this information in a configuration management program. If that isn’t the case, or if you want to be certain you have the most current information, you should collect it now. Most routers, switches, and servers have a configuration that you can easily copy to a disk.

5. Prevent users from accessing the system or the part of the system that you are changing.

6. Keep the installation instructions and hardware documentation handy.

7. Implement the change.

8. Test the hardware fully after the change, preferably putting a higher load on the device than it would incur during normal use in your organization. Note any unintended or unanticipated consequences of the change.

9. If the change was successful, reenable access to the device. If it was unsuccessful, isolate the device or reinsert the old device, if possible.

10. Inform system administrators, help desk personnel, and users when the change is complete. If it was not successful, make that known and explain why.

11. Record your change in the change management system.

Adding or Upgrading Equipment

The difficulty involved in adding or upgrading hardware on your network depends largely on whether you have used the hardware in the past. For instance, if your organization always uses Cisco switches, adding one more Cisco switch to your second-floor telecommunications closet might take only a few minutes and cause absolutely no disruption of service to your users. On the other hand, even if your company uses Cisco switches, adding a Cisco VPN router to your network might be an entirely new experience. Therefore, take time to research, evaluate, and test any unfamiliar piece of equipment that you intend to add or upgrade on your network, even if it is manufactured by a vendor that supplies much of your other hardware. With the rapid changes in the hardware industry, you might not be able to purchase identical hardware even from one quarter to the next. If consistency is a concern—for example, if your technical staff is familiar with only one brand and model of network printer, and you do not have the time or money to retrain personnel—you would be wise to purchase as much hardware as possible in a single order. If this approach is not feasible, purchase equipment from vendors with familiar products and solid reputations. Each type of device that you add or upgrade on the network will have different preparation and implementation requirements. Knowing exactly how to handle the changes requires not only a close reading of the manufacturer’s instructions, but also some experience with the type of networking equipment at hand.

The following list provides a very general overview of how you might approach adding or upgrading devices on the network, from the least disruptive to the most complex types of equipment. The devices at the bottom of the list are not only the most disruptive and complex to add or upgrade, but also the most difficult to remove or backlevel.

Networked workstation—A networked workstation is perhaps the simplest device to add. It directly affects only a few users, and does not alter network access for anyone else. If your organization has a standard networked workstation configuration (for example, a disk image, or a compressed snapshot of the workstation’s contents, on the server), adding a networked workstation will be a quick operation as well. You can successfully add a networked workstation without notifying users or support staff and without worrying about downtime.

Networked printer—A networked printer is easy to add to your network, too. Adding this equipment might be more complex than adding a workstation, however, because of its unique configuration process and because it is shared. Although it affects multiple users, a networked printer does not typically perform a mission-critical function in an organization, so the length of time required to install one does not usually affect productivity. Thus, although you should notify the affected users of a networked printer addition, you do not need to notify all users and support staff. Likewise, you do not need to restrict access to the network or worry about downtime in this instance.

Workgroup switch or access point—A single workgroup switch or access point might service as few as one or as many as 64 users. You do not have to worry about downtime or notifying users when adding a new workgroup switch or access point because it cannot affect anyone until it is actually in use. However, if you are upgrading or swapping out an existing workgroup switch or access point during working hours, you must notify the affected users because the upgrade or swap will create downtime, if only a few seconds. In addition, consider the traffic and addressing implications of adding or upgrading a workgroup switch or access point. For example, if you need to expand the capacity of a TCP/IP-based network segment from 24 users to 60 users, you can easily enough swap your 24-port switch with a 64-port switch. But before doing so, make sure that the segment has been allotted enough free IP addresses to service 60 users; otherwise, these users will not be able to access the network.

Server—A server addition or upgrade can be tricky. Typically, this type of change (unless it is the replacement of a minor component) requires a great deal of foresight and planning. Before installing a new server, you need to consider the hardware and connectivity implications of the change, as well as issues relating to the NOS. Even if you are adding a server that will not be used immediately, you still need to plan for its installation. It’s preferable to add the server while network traffic is low or nonexistent. Also, restrict access to the new server; otherwise, one of your users could find the server while browsing the network and try to save files to it or run an application from it. Upgrading the hardware (such as a NIC or memory) on an existing server may require nearly as much planning as adding an entirely new server. Schedule upgrades to an existing server for off-hours, so that you can shut down the server without inconveniencing any users who rely on it.

Backbone switches and routers—Changing or adding backbone switches or routers to a network design can be complicated for several reasons. First, this type of change can be physically disruptive—for example, it might require the installation of new racks or other support frames in your telecommunications room. Second, backbone switches and routers usually affect many users—and might affect all users—on the network.

For instance, if you must replace the Internet gateway for your organization’s headquarters, you will cut every user’s access to the Internet in the process (unless you have redundant gateways, which are the optimal setup if you rely on the Internet for mission-critical services). You should notify all users on the network about the impending change, even if you don’t think they will be affected, because a backbone router or switch might affect segments of the network other than the one it services. In addition, you should plan at least weeks in advance for switch or router changes and expect at least several hours of downtime. Because enterprise switches and routers are expensive, take extraordinary care when handling and configuring this type of equipment. Also, because switches and routers serve different purposes, rely on the manufacturer’s documentation to guide you through the installation process.

Bear in mind that adding a new processor to a server, a new NIC to

a router, or more memory to a printer may affect your service or

warranty agreement with the manufacturer. Before purchasing any

components to add or replace in your network devices, check your

agreement for stipulations that might apply. You may be allowed to

add only components made by the same manufacturer, or risk losing

all support from that manufacturer.

Above all, keep safety in mind when you upgrade or install hardware on a network. Never tinker with the inside of a device that is turned on. Make sure that all cords and devices are stowed safely out of the way and cannot cause trips or falls. Avoid wearing jewelry, scarves, or very loose clothing when you work on equipment; if you have long hair, tie it back. Not only will you prevent injury this way, but you will also be less distracted. By removing metal jewelry, you could prevent damage to the equipment caused by a short if the metal touches a circuit. If the equipment is heavy (such as a large switch or server), do not try to lift it by yourself. Finally, to protect the equipment from damage, follow the manufacturer’s temperature, ventilation, antistatic, and moisture guidelines.

Cabling Upgrades

Cabling upgrades, unless they involve the replacement of a single faulty patch cable, can require significant planning and time to implement, depending on the size of your network. Bear in mind that troubleshooting cabling problems can be made easier by maintaining current, accurate wiring schematics. If the network’s cable layout is undocumented and poorly planned, particularly if it was installed years before and survived intact despite building changes and network growth, cabling changes will be more difficult. The best way to ensure that future upgrades go smoothly is to carefully document the existing cable before making any upgrades. If this assessment is not possible, you might have to compile your documentation as you upgrade the existing cabling. Because a change of this magnitude affects all users on the network, consider upgrading the network cabling in phases. For example, schedule an upgrade of the first-floor east wing of your building one weekend, then the first-floor west wing of your building the next, and so on. Weigh the importance of the upgrade against its potential for disruption. For example, if the Payroll Department is processing end-of-month checks and having no difficulties other than somewhat slow response time, it is not critical to take away its access to install Cat 6a wiring. On the other hand, if the building maintenance staff needs a 1-Gbps connection to run a new HVAC control system, you will probably make it a priority to take down this access temporarily and replace the wiring. In this case, not only must you replace the wiring, but you might also need to replace switches and NICs. For the most part, organizations that run very small networks are able to upgrade or install their own network cabling.

Many other organizations rely on contractors who specialize in this service. Nevertheless, as a networking professional you should know how to run a cable across a room, either under a raised floor or through a ceiling plenum, in order to connect a device to the network.

Backbone Upgrades

The most comprehensive and complex upgrade involving network hardware is a backbone upgrade. Recall that the network backbone is the main conduit for data on LANs and WANs, connecting major routers, servers, and switches. A backbone upgrade requires not only a great deal of planning, but also the efforts of several personnel (and possibly contractors) and a significant investment. You may upgrade parts of the backbone—a NIC in a router or a section of cabling, for example—at any time, but upgrading the entire backbone changes the whole network. Examples of backbone upgrades include migrating from token ring to Ethernet, migrating from a slower technology to a faster one, and replacing routers with switches (to make use of VLANs, for example). Such upgrades may satisfy a variety of needs: a need for faster throughput, a physical move or renovation, a more reliable network, greater security, more consistent standards, support of a new application, or greater cost-effectiveness. For example, the need for faster throughput may prompt an upgrade from an older Ethernet technology to Gigabit Ethernet. Likewise, the need to support videoconferencing may require a backbone upgrade from Cat 5 to fiber-optic cable. Because backbone upgrades are expensive and time consuming, the first step in approaching such a project is to justify it. Will the benefits outweigh the costs? Can the upgrade wait a year or more? If so, you might be wise to wait and find out whether a cheaper or better technical solution becomes available later. Don’t plan to wait until the technology “settles down” because networking progress never stands still. On the other hand, do wait to implement brand-new technology until you can find out how it has worked on other networks similar to your own or until the manufacturer eliminates most of the bugs. The second step is to determine which kind of backbone design to implement. To make this decision, you must analyze the future capacity needs of your network, decide whether you want a distributed or collapsed backbone, determine whether you want to rely on switches or routers, decide whether to use subnetting and to what extent, and so on. Although some of these predictions will be guesswork, you can minimize the variables by examining the history of your organization’s growth and needs. After designing your backbone upgrade, develop a project plan to accomplish the upgrade. Given that you don’t upgrade your backbone every day, you might want to contract this work to a firm that specializes in network design and upgrades. In that case, you will draft an RFP (request for proposal) to specify what that contractor should do. Regardless of whether you employ specialists, your project plan should include a logical process for upgrading the backbone one section at a time (if possible). Because this process causes network outages, determine how best to proceed based on users’ needs. Choose a time when usage is low, such as over a holiday, to perform your upgrade.

Reversing Hardware Changes

As with software changes, you should provide a way to reverse the hardware upgrade and reinstall the old hardware if necessary. If you are replacing a faulty component or device, this restoration, of course, is not possible. If you are upgrading a component in a device, on the other hand, keep the old component safe (for example, keep NICs in static-resistant containers) and nearby. Not only might you need to put it back in the device, but you might also need to refer to it for information. Even if the device seems to be operating well with the new component, keep the old component for a while, especially if it is the only one of its kind at your organization.

Chapter Summary

■ Network management involves assessing, monitoring, and maintaining network devices and connections.

■ Documenting all aspects of your network promises to save work in the future. Information to track includes, but is not limited to, physical topology, access method, protocols, devices, operating systems, applications, and configurations.

■ Configuration management refers to the collection of information related to the versions of software installed on every network device and every device’s hardware configuration.

■ Network diagrams illustrate a network’s physical or logical topology. A wiring schematic is a graphical representation of a network’s wired infrastructure. Both are helpful for assessing a network’s status and planning for its expansion.

■ Baselining includes keeping a history of network performance and provides the basis for determining what types of changes might improve the network. It also allows for later evaluating how successful the improvements were.

■ Policies, procedures, and regulations are important elements of sound network management. Elsewhere in this book, you have learned about media installation and management best practices, network addressing policies, resource sharing and naming conventions, security-related policies, troubleshooting procedures, and backup and disaster recovery procedures.

■ CALEA (Communications Assistance for Law Enforcement Act) is a federal regulation that requires telecommunications carriers and equipment manufacturers to provide for surveillance capabilities. HIPAA (Health Insurance Portability and Accountability Act) addresses, among other things, the security and privacy of medical records, including those stored or transmitted electronically. These are just two laws that, depending on where you work, might affect your responsibilities as a network professional.

■ Assessing a network’s status on an ongoing basis includes performance management, or monitoring how well links and devices are keeping up with the demands placed on them, and fault management, or the detection and signaling of device, link, or component faults.

■ Network management applications typically use SNMP (Simple Network Management

Protocol) to communicate with agents running on managed devices. Agents can report information on a device’s components or status (such as utilization or performance).

■ The most recent version of SNMP is SNMPv3, which applies authentication, validation, and encryption to packets exchanged between managed devices and the network management console. SNMPv2, which is less secure, is also widely used.

■ System logs and event logs keep a record of conditions reported by operating systems and applications. On a Windows-based computer, the Event Viewer allows you to review the computer’s event log. UNIX and Linux systems run syslog, a standard for generating and collecting event information that stores messages in a system log. To find out where your computer’s system log is kept, view the /etc/syslog.conf file.

■ Traffic shaping helps ensure acceptable overall network performance by limiting the throughput or volume of traffic that may traverse certain network interfaces or by assigning variable priority levels to different types of traffic.

■ Caching stores files locally that would otherwise be obtained from a remote source, such as a Web server across the country. An ISP uses cache engines on its network to store frequently accessed content and deliver it directly to requesters. In this way, the ISP improves response time and reduces WAN traffic and costs.

■ An asset management system includes an inventory of the total number of components on the network as well as each device’s configuration files, model number, serial number, location on the network, and technical support contact. In addition, it records every piece of software purchased by your organization, its version number, vendor, and technical support contact.

■ A patch is an enhancement or improvement to a part of a software application, often distributed at no charge by software vendors to fix a bug, address a vulnerability, or add slightly more functionality.

■ An application upgrade consists of modifications to all or part of an application that are designed to enhance functionality or fix problems with the software.

■ Perhaps the most critical type of software upgrade you’ll perform is an upgrade to your network operating system. This type of upgrade usually involves significant, potentially drastic, changes to the operation of your servers and clients. As such, it requires plenty of forethought, product research, and rigorous testing before you implement it. In fact, for any network with more than a few users, you should create and follow a project plan for this undertaking.

■ Plan for the possibility that a software upgrade might harm your existing system, and be prepared to reverse the process. The restoration of a previous version of software after an attempted upgrade is known as backleveling.

■ Hardware and physical plant changes might be required when your network has problems. More often, however, they are performed as part of a move to increase  capacity, improve performance, or add functionality to the network.

■ Research, evaluate, and test any unfamiliar piece of equipment you intend to add or upgrade on your network, even if it is manufactured by a vendor that supplies much of your other hardware. The process of implementing a hardware upgrade is very similar to that of carrying out a software upgrade, including notifying users and preparing to bring the system down during the change.

■ Cabling upgrades are simpler and less error-prone if a network’s cable plant is well documented. Also make sure to document new cable infrastructure after making changes. When embarking on a major cabling upgrade, such as a backbone replacement, it is advisable to upgrade the infrastructure in phases.

■ The most comprehensive and complex upgrade involving network hardware is a backbone upgrade. The network backbone serves as the main conduit for data on LANs and WANs, connecting major routers, servers, and/or switches. A backbone upgrade not only requires a great deal of time to plan, but also the efforts of several staff members (and possibly contractors) and a significant investment.

■ Allow for a way to reverse a hardware upgrade and replace it with the old hardware. If you are upgrading a component in a device, keep the old component safe and nearby. Not only might you need to put it back in the device, but you might also need to refer to it for information.

Key Terms

Ø  agent - A software routine that collects data about a managed device’s operation and provides it to the network management application running on the console.

Ø  backleveling - The process of reverting to a previous version of a software application after attempting to upgrade it.

Ø  cache engine - A network device devoted to storage and delivery of frequently requested files.

Ø  caching - The local storage of frequently needed files that would otherwise be obtained from an external source.

Ø  CALEA (Communications Assistance for Law Enforcement Act) - A United States federal regulation that requires telecommunications carriers and equipment manufacturers to provide for surveillance capabilities. CALEA was passed by Congress in 1994 after pressure from the FBI, which worried that networks relying solely on digital communications would circumvent traditional wiretapping strategies.

Ø  Communications Assistance for Law Enforcement Act - See CALEA.

Ø  configuration management - The collection, storage, and assessment of information related to the versions of software installed on every network device and every device’s hardware configuration.

Ø  event log - The service on Windows-based operating systems that records events, or the ongoing record of such events.

Ø  Event Viewer - A GUI application that allows users to easily view and sort events recorded in the event log on a computer running a Windows-based operating system.

Ø  fault management - The detection and signaling of device, link, or component faults.

Ø  Health Insurance Portability and Accountability Act - See HIPAA.

Ø  HIPAA (Health Insurance Portability and Accountability Act) - A federal regulation in the United States, enacted in 1996. One aspect of this regulation addresses the security and privacy of medical records, including those stored or transmitted electronically.

Ø  Management Information Base - See MIB.

Ø  MIB (Management Information Base) - A database used in network management that contains a device’s definitions of managed objects and their data.

Ø  network diagram - A graphical representation of a network’s devices and connections.

Ø  network management - The assessment, monitoring, and maintenance of the devices and connections on a network.

Ø  patch - A correction, improvement, or enhancement to part of a software application, often distributed at no charge by software vendors to fix a bug in their code or to add slightly more functionality.

Ø  performance management - The ongoing assessment of how well network links, devices, and components keep up with demands on them.

Ø  polling - A network management application’s regular collection of data from managed devices.

Ø  Simple Network Management Protocol - See SNMP.

Ø  Simple Network Management Protocol version 1 - See SNMPv1.

Ø  Simple Network Management Protocol version 2 - See SNMPv2.

Ø  Simple Network Management Protocol version 3 - See SNMPv3.

Ø  SNMP (Simple Network Management Protocol) - An Application layer protocol in the TCP/IP suite used to convey data regarding the status of managed devices on a network.

Ø  SNMPv1 (Simple Network Management Protocol version 1) - The original version of SNMP, released in 1988. Because of its limited features, it is rarely used on modern networks.

Ø  SNMPv2 (Simple Network Management Protocol version 2) - The second version of SNMP, which improved on SNMPv1 with faster performance and slightly better security, among other features.

Ø  SNMPv3 (Simple Network Management Protocol version 3) - A version of SNMP similar to SNMPv2, but with authentication, validation, and encryption for packets exchanged between managed devices and the network management console. SNMPv3 is the most secure version of the protocol.

Ø  syslog - A standard for generating, storing, and processing messages about events on a system. Syslog describes methods for detecting and reporting events and specifies the format and contents of messages.

Ø  system log - On a computer running a UNIX or Linux operating system, the record of monitored events, which can range in priority from 0 to 7 (where “0” indicates an emergency situation and “7” simply points to information that might help in debugging a problem). You can view and modify system log locations and configurations in the file /etc/syslog.conf file on most systems (on some systems this is the /etc/rsyslog. conf file).

Ø  traffic policing - A traffic-shaping technique in which the volume or rate of traffic traversing an interface is limited to a predefined maximum.

Ø  traffic shaping - Manipulating certain characteristics of packets, data streams, or connections to manage the type and amount of traffic traversing a network or interface at any moment.

Ø  upgrade - A significant change to an application’s existing code, typically designed to improve functionality or add new features.

Ø  Web caching - A technique in which Web pages are stored locally, either on a host or network, and then delivered to requesters more quickly than if they had been obtained from the original source.

Ø  wiring schematic - A graphical representation of a network’s wired infrastructure.

Review Questions

1.   Which of the following practices creates a starting point for ongoing evaluation of  our network's health?

a.   Configuration management

b.   Asset management

c.   Fault management

d.  Baselining

2.   Suppose you learned that half of the patch cables that connect a workgroup of computers in the Accounting Department to a patch panel needed to be replaced due to concerns about faulty manufacturing. Which of the following types of documentation would help you identify these patch cables?

a.   Event log

b.   Baseline

c.   Wiring schematic

d.   Syslog

3.   You work for a medical transcription company that contracts with hundreds of home- based transcriptionists across the country. The transcriptionists connect to your network over a VPN that provides remote access services. Employees work at all times of the day or night, and not all of the transcriptionists are connected at the same time. Further, the number of transcriptionists the company hires at any time depends on a variable workload. You need to determine whether to increase the number of licenses on your remote access server. Which of the following variables would you configure your network monitoring application to track over time to help you find your answer?

a.   % utilization on the VPN router's CPU

b.   Maximum traffic handled by the VPN router's NIC

c.   Number of users connected to the remote access server

d.   % utilization on the remote access server's CPU

4.   You have researched a new type of switch and proved that upgrading your switches to this model is feasible. What is the next step you take before replacing your old switches?

a.   Evaluate the new switch on a pilot network that mimics your network environment.

b.   Inform users that a major network change is pending.

c.   Back up the configurations of your existing switches.

d.   Schedule a time for the switch upgrade that's least disruptive to users.

5.   You suspect that one of your network's two redundant core switches has a NIC or cable that's experiencing transmission problems. Supposing you never obtained a baseline for traffic on this switch, which of the following measurements would help you verify your suspicion?

a.   % processor utilization on the affected switch over a week

b.  Total bits per second traveling through the affected switch, compared to total bits per second traveling through the redundant switch

c.   % RAM utilization on the affected switch over a week

d.   Average daily traffic on the affected switch

6.   Which of the following protocols is commonly used for communication between network management agents and applications?

a.   IMAP

b. SMTP

c.   NTP

d.  SNMP

7.   Which of the following applications would allow you to determine how many times in the past seven days your Windows 7 workstation has been unable to renew its DHCP-assigned IP address?

a.   Event Viewer

b.   DHCP logger

c.   Syslog

d.   TCP/IP Properties

8.   On your Linux server, what file tells you where your system log file is kept?

a.   /var/log/logs.conf

b.  /etc/syslog.conf

c.   /etc/usr/logs.conf

d.   /var/syslog.conf

9.   Which of the following techniques could be used to prevent clients from downloading more than 50 GB of data per day through a given network interface?

a.   Caching

b.   Load balancing

c.   Traffic policing

d.   Clustering

10. You have decided to use an application that will send a text message to your smartphone every time one of your network’s core routers or switches experiences an event that the system considers an emergency. All switches and routers run Cisco IOS. The application will alert you about events identified with which of the following severity levels?

a. 0

b. 1

c. 5

d.   7

11. Suppose you work for a financial institution that wants to make sure its clients can log on and review their accounts no matter how much traffic your WAN is experiencing. On your edge router which of the following criteria will you use to prioritize traffic for all HTTPS requests?

a.   Protocol

b.   Source IP address

c.   Source MAC address

d.   Time of day

12. An asset management database should include which of the following? (Choose all that apply.)

a.   Serial number for every server on the network

b.   User names for every employee who uses the network

c.   Model number for every router, switch, and access point on the network

d.   Baseline of average daily traffic for each router, switch, and access point on the network

e.   Milestones for the network's implementation

13. The routine that collects management information on a device is also known as:

a.   An agent

b.   A poll

c.   A managed device

d.   A MIB

14. How does an application patch differ from an upgrade?

a.   A patch is more comprehensive than an upgrade.

b.  A patch is designed to make minor corrections or enhancements, whereas an upgrade replaces most, if not all, of the software code.

c.   A patch is offered by a third-party software vendor, whereas an upgrade is supplied by the software manufacturer itself.

d.   A patch can be automatically distributed to clients over the network, whereas an upgrade requires a manual installation.

15. Under what circumstances should a network administrator inform users of a software change?

a.   Always

b.  When the change might affect applications or utilities on which the users rely

c.   When the change might result in additional network traffic

d.   When the change might affect how users are added to the system

16. Which of the following systems would store information about the VTP settings for a switch’s interface?

a.   Change management

b.   Event log

c.   Configuration management

d.   Asset management

17.  Which of the following is the best way to reverse a network operating system upgrade?

a.   Reinstall the previous version of the operating system.

b.   Uninstall the upgrade.

c.   Remove the upgrade software folder from the server.

d.  Restore the server's software and configuration from a backup.

18.  Which of the following require(s) authentication between an agent and network management console?

a. SNMPv1

b. SNMPv2

c. SNMPv3

d. All of the above

19. Which of the following pieces of information must you collect when establishing a baseline for the performance of a WAN link?

a.   Last time the link failed

b.  Average daily traffic traveling over the link

c.   Users' perceptions of the link's speed

d.  Distribution of traffic types by Network layer protocol

20. Maintaining records of each time a switch interface fails is part of which of the following practices?

a.   Asset management

b.   Change management

c.   Fault management

d.   Configuration management

Practice Test

1. True or False: The scope of network management techniques differs according to the network’s size and importance.

a.       True

b.      False

2. The term ____ is frequently used to describe a flaw in a software application that causes some part of the application to malfunction.

a.       bug

b.      patch

c.       service pack

d.      system log

3. The most critical type of software upgrade a network professional will perform is an upgrade to the ____________________.

NOS

 4. If you are replacing a(n) ____ hardware component or device, restoration is not possible

a.       faulty

b.      live

c.       important

d.      critical

5. The network management protocol that provides for both authentication and encryption is ____.

a.       SMTP

b.      SNMPv1

c.       SNMPv2

d.      SNMPv3

6. A patch is typically a replacement for an entire software package.

a.       True

b.      False

7. A(n) ____ is a graphical representation of a network's wired infrastructure. In its most detailed form, it shows every wire necessary to interconnect network devices.

a.       wiring schematic

b.      cache engine

c.       event log

d.      patch

8. The term ____ originally referred to an organization's system for keeping tabs on every piece of equipment it owned.

asset management

 

 9. Much of the information collected in event logs and syslog files does not point to a problem, even if it is marked with a warning.

a.       True

b.      False

10.  ____ are graphical representations of a network's devices and connections.

network diagrams

 

11. Examples of ____ include migrating from token ring to Ethernet, migrating from a slower technology to a faster one, and replacing routers with switches (to make use of VLANs, for example).

backbone upgrades

 

12. A patch is a form of a(n) ____ change.

a.       hardware

b.      software

c.       monitoring

d.      asset

13. Network traffic patterns might be difficult to forecast, because you cannot predict users' habits, effects of new technology, or changes in demand for resources over a given period of time.

a.       True

b.      False

14. An up-to-date asset management system allows you to avoid searching through old invoices and troubleshooting records to answer.

a.       True

b.      False

15. The term ____ refers to the detection and signaling of device, link, or component faults.

fault management

 

16. The term ____ refers to monitoring how well links and devices are keeping up with the demands placed on them.

a.       traffic shaping

b.      performance management

c.       polling

d.      fault management

17. The first step in asset management is to take an inventory of each node on the network.

a.       True

b.      False

18. Because of its status in the networking world and the volume of networking hardware it sells, ____________________ has set trends for network diagramming.

Cisco

 

19.   ____________________ upgrades affect all users at once.

Shared application

 

20. Traffic shaping can involve delaying less important traffic, increasing the priority of more important traffic, limiting the volume of traffic flowing in or out of an interface during a specified time period, or limiting the momentary throughput rate for an interface.

a.       True

b.      False

21. In addition to internal policies, a network manager must consider ____ regulations that might affect her responsibilities.

a.       state

b.      federal

c.       state and federal

d.      local

22.  ____ simplifies maintaining and upgrading the network chiefly because you know what the system includes.

a.       Performance management

b.      Polling

c.       Asset management

d.      Network management

Chapter Test

1.  The most comprehensive and complex upgrade involving network hardware is a ____ upgrade.

a.       NOS

b.      cabling

c.       printer

d.      backbone

2. For a cabling upgrade, the best way to ensure that future upgrades go smoothly is to carefully document the existing cable after making any upgrades.

a.       True

b.      False

3. A ____ is a correction, improvement, or enhancement to a software application.

a.       revision

b.      patch

c.       change

d.      software upgrade

4.  ____ management is the collection, storage, and assessment of information related to the versions of software installed on every network device and every device’s hardware configuration.

a.       Performance

b.      Configuration

c.       Change

d.      Asset

5. The process of reverting to a previous version of software after attempting to upgrade it is known as ____.

a.       backleveling

b.      downgrading

c.       reverse engineering

d.      change back

6. The most critical type of software upgrade you will perform is an upgrade to your ____.

a.       application

b.      NOS

c.       database

d.      backbone

7. A network management agent is a ____ that collects information about a device’s operation and provides it to the network management application.

a.       hardware device

b.      software routine

c.       GUI

d.      probe

8. The most common type of caching is ____ caching.

a.       online

b.      device

c.       Internet

d.      Web

9. A key component in managing networks is identifying and tracking its hardware and software through ____ management.

a.       asset

b.      change

c.       configuration

d.      performance

10. A(n) ____ is a graphical representation of a network’s devices and connections.

a.       network diagram

b.      event viewer

c.       wiring schematic

d.      Multi Router Traffic Grapher

11. Because backbone upgrades are expensive and time consuming, the first step in approaching such a project is to ____ it.

a.       research

b.      justify

c.       document

d.      plan

12. A networked ____ is perhaps the simplest device to add.

a.       server

b.      hub

c.       workstation

d.      printer

13.  ____ is the local storage of frequently needed files that would otherwise be obtained from an external source.

a.       Segmentation

b.      Paging

c.       Swapping

d.      Caching

14. The first step in configuration management is to take an inventory of each node on the network.

a.       True

b.      False

15. The more data you gather while establishing your network’s baseline, the less accurate your prediction will be.

a.       True

b.      False

16. A(n) ____ is a graphical representation of a network’s wired infrastructure.

a.       event viewer

b.      wiring schematic

c.       Multi Router Traffic Grapher

d.      network diagram

17. The definition of managed devices and their data are collected in a(n) ____________________.

MIB

18. The process where one network management console collects data from multiple networked devices at regular intervals is known as ____.

a.       interrogating

b.      base lining

c.       pushing

d.      polling

19.  ____________________ refers to the assessment, monitoring, and maintenance of all aspects of a network.

Network management

20. Above all, keep ____ in mind when you upgrade or install hardware on a network.

a.       time

b.      safety

c.       costs

d.      user inconvenience

21. Documenting and capturing an accurate picture of a network’s physical and logical elements are initial steps in understanding the network.

a.       True

b.      False

 22.  A(n) ____________________ is a report of the network’s current state of operation.

baseline

23. A ____ is a network device devoted to storage and delivery of frequently requested files.

a.       server

b.      cache engine

c.       Web site host

d.      database host

24.  ____ upgrades typically overwrite some system files on the workstation, so their installation may affect other applications adversely.

a.       Patch

b.      Application

c.       Principle

d.      Full

25.  ____ management refers to monitoring how well links and devices are keeping up with the demands placed on them.

a.       Performance

b.      Configuration

c.       Network

d.      Fault