with the physical layer at the user-site can be eliminated. Effective questioning techniques can discover this type of information without requiring a trip to the end-user location. The commands shown in the figure can be used to check the status of various devices and be used to determine which configuration aspects to inspect. The troubleshooter should use effective questioning techniques to document the symptoms of a problem:

Ask questions that are pertinent to the problem.
Use each question as a means to either eliminate or discover possible problems.
Speak at a technical level that the user can understand.
Ask the user when the problem was first noticed.
Ask the user to re-create the problem, if possible.
Determine the sequence of events that took place before the problem happened.
Match the symptoms that the user describes with common problem causes.

Content 2.3 Gathering Symptoms 2.3.4 Questions to ask an end-user When asking an end user questions, it is important to follow a specific sequence to allow the troubleshooter to gain the knowledge necessary to attain a solution. A typical format for interviewing an end user concerning their problem is:

What does not work?
What does work?
Are the things that do and do not work related?
Has the thing that does not work ever worked?
When the problem was first noticed?
What has changed since the last time it did work?
Did anything unusual happen since the last time it worked?
When exactly does the problem occur?
Can the problem be reproduced and if so, how can it be reproduced?

Content 2.3 Gathering Symptoms 2.3.5 Flow charts for gathering network and end-user symptoms Stage 1 Interview user – If possible, a troubleshooter gathers initial symptoms from the user and uses these symptoms as a basis for additional troubleshooting. Stage 2 Analyze symptoms – A troubleshooter will get a description of the problem by analyzing any gathered symptoms from the user Stage 3 Determine symptoms – Using a layered troubleshooting approach, a troubleshooter gathers hardware and software symptoms from the end system starting with the most likely cause. The troubleshooter should rely on previous experience, if possible, to decide if the problem is more likely a hardware or software problem. Stage 4 Document symptoms – Document any hardware and software symptoms. If the problem can be solved using the documented symptoms, a troubleshooter solves the problem and documents the solution. If the problem cannot be solved at this point, then the isolating phase of the general troubleshooting process is initiated. Lab Activity Lab Exercise: Gathering Symptoms After completing this lab, the student will be able to decide what questions to ask and which troubleshooting tools to use to completely document the symptoms of a network problem.

Content 2.4 Network Management Tools 2.4.1 Network management system frameworks Network management can range from a solitary network consultant monitoring network activity with a simple protocol analyzer, to the use of a distributed database with auto-polling of network devices. Network management could even include the use of high end workstations generating real time graphical views of network topology changes and traffic. In general, network management is a service that employs a variety of tools, applications, and devices to assist network managers in monitoring and maintaining networks. Most network management architectures use the same basic structure and set of relationships. End stations, or managed devices, such as computer systems and other network devices, run software that enables them to send alerts when they recognize problems. An example would be when one or more user determined thresholds are exceeded. Upon receiving these alerts, management entities are programmed to react by executing one action, or a group of actions. This would include operator notification, event logging, system shutdown, or automatic attempts at system repair. Management entities can also poll end stations to check the values of certain variables. Polling can be automatic or user initiated, but agents in the managed devices respond to all polls. Agents are software modules that first compile information about the managed devices in which they reside, and then store this information in a management database. Finally agents provide information proactively or reactively to management entities within network management systems (NMSs) via a network management protocol. Well known network management protocols include the Simple Network Management Protocol (SNMP) and Common Management Information Protocol (CMIP). Management proxies are entities that provide management information on behalf of other entities. Figure depicts a common network management architecture. The International Organization for Standardization (ISO) has contributed a great deal to network standardization. The organization's network management model is the primary means for understanding the major functions of NMSs. This model consists of five conceptual areas:

Performance management – The goal is to measure and provide various aspects of network performance in order to maintain internetwork performance at an acceptable level. Examples of performance variables include network throughput, user response times, and line utilization.
Configuration management – The goal is to monitor network and system configuration information so that the effects on network operation of various versions of hardware and software elements can be tracked and managed.
Accounting management – The goal is to measure network-utilization parameters so that individual or group use of the network can be regulated appropriately. Such regulation minimizes network problems because network resources can be apportioned based on resource capacities, and maximizes the fairness of network access among users.
Fault management – The goal is to detect, log, notify users of, and if possible, automatically fix network problems to keep the network running effectively. Because faults can cause downtime or unacceptable network degradation, fault management is perhaps the most widely implemented of the ISO network management elements.
Security management – The goal is to control access to network resources to prevent the network from being sabotaged or unintentionally brought down, and to prevent sensitive information from being accessed by unauthorized users. A security management subsystem can monitor users logging on to a network resource and deny access to those who enter inappropriate access codes.

Content 2.4 Network Management Tools 2.4.2 Knowledge base tools Knowledge bases represent an invaluable tool for the network troubleshooter. The most visible example of a knowledge base is the Internet. It has become a very valuable tool for many individuals seeking answers on specific problems. It potentially represents a vast pool of experience based information. A knowledge base is often a database collection of empirical information on a specific technical area. It consists of real solutions to problems encountered on a single or on numerous occasions. The art in knowledge base tools is in the identification of keywords or phrases that are associated with particular problems and problem areas. With highly developed Internet search engines, standardized methods for cataloging information mean that it is relatively easy to present a knowledge base in a user-friendly web browser format. The Cisco Systems website reached at http://www.cisco.com/ incorporates a free knowledge base tool on Cisco related hardware and software. This site represents an invaluable troubleshooting resource for Cisco customers, support staff, and design personnel. It contains