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Chapter 08 network troubleshooting
Chapter 8: Network Troubleshooting CCNA Exploration 4.0 2 Objectives • Establish and document a network baseline. • Describe the various troubleshooting methodologies and troubleshooting tools. • Describe the common issues that occur during WAN implementation. • Identify and troubleshoot common enterprise network implementation issues using a layered model approach. 3 Establishing the Network Performance Baseline 4 Documenting Your Network • To efficiently diagnose and correct network problems, a network engineer needs to know how a network has been designed and what the expected performance for this network should be under normal operating conditions. This information is called the network baseline. • Network documentation should include these components: – Network configuration table – End-system configuration table – Network topology diagram 5 Network configuration table • Contains accurate, up-to-date records of the hardware and software used in a network. 6 End-system Configuration Table • Contains baseline records of the hardware and software used in end-system devices such as servers, network management consoles, and desktop workstations. 7 Network Topology Diagram • Graphical representation of a network, which illustrates how each device in a network is connected and its logical architecture. 8 Documenting Your Network 9 Network Documentation Process • When you document your network, you may have to gather information directly from routers and switches. Commands that are useful to the network documentation process include: – The ping command – The telnet command – The show ip interface brief command – The show ip route command – The show cdp neighbor detail command 10 Documenting Your Network [...]... establish a typical picture of the network 14 Steps for Establishing a Network Baseline Measuring Network Performance Data • Automated Data Collection: Fluke Network SuperAgent module 15 Steps for Establishing a Network Baseline Measuring Network Performance Data • Manual Commands 16 Troubleshooting Methodologies and Tools 17 A General Approach to Troubleshooting • • • Network engineers, administrators,... Knowledge Bases 29 Software Troubleshooting Tools • Baselining Tools 30 Software Troubleshooting Tools • Protocol Analyzers 31 Hardware Troubleshooting Tools • Network Analysis Module (NAM) 32 Hardware Troubleshooting Tools Digital Multimeters Cable Testers 33 Hardware Troubleshooting Tools Cable Analyzers Portable Network Analyzers 34 Research Activity • • Software Tools – Network Management Systems:... otherwise wasted with trial and error 19 Using Layered Models for Troubleshooting • OSI Versus TCP/IP Layered Models 20 General Troubleshooting Procedures • General troubleshooting process: 21 Troubleshooting Methods • • There are three main methods for troubleshooting networks: – Bottom up – Top down – Divide and conquer Bottom-Up Troubleshooting Method – Good approach to use when the problem is suspected... http://www.cisco.com/en/US/docs/net_mgmt /network_ analysis_module_software/3.5/user/gui de/user.html – Cable Testers: • http://www.flukenetworks.com/fnet/en-us/products/CableIQ+Qualification+Tester/Demo.htm – Cable Analyzers: • http://www.flukenetworks.com/fnet/en-us/products/DTX+CableAnalyzer+Series/Demo.htm – Network Analyzers: • http://www.flukenetworks.com/fnet/enus/products/OptiView+Series+III+Integrated +Network+ Analyzer/Demos.htm... http://www.solarwinds.com/products /network_ tools.aspx • http://h20229.www2.hp.com/products/cvnnm/ds/cvnnm_ds.pdf – Baselining Tools: • http://www.networkuptime.com/tools/enterprise/ • http://www.neon.com/Tutorials/index.html?drawyournetworkmap.htm – Knowledge Bases: • http://www.cisco.com – Protocol Analyzers: • http://www.flukenetworks.com/fnet/en-us/products/OptiView+Protocol+Expert/ Hardware Tools – Cisco Network Analyzer... problem is found 22 Troubleshooting Methods • • Top-Down Troubleshooting Method – Use for simpler problems or when you think the problem is with a piece of software – Disadvantage: requires checking every network application until the possible cause of the problem is found Divide-and-Conquer Troubleshooting Method – You select a layer and test in both directions from the starting layer 23 Troubleshooting. .. Troubleshooting Method 24 Gathering Symptoms • • • • • Step 1 Analyze existing symptoms Step 2 Determine ownership Step 3 Narrow the scope Step 4 Gather symptoms from suspect devices Step 5 Document symptoms 25 Gathering Symptoms • Use the Cisco IOS commands to gather symptoms about the network 26 Gathering Symptoms • Questioning End Users 27 Software Troubleshooting Tools • NMS Tools 28 Software Troubleshooting. ..Why Is Establishing a Network Baseline Important? 11 Steps for Establishing a Network Baseline • • Planning for the First Basline Step 1 Determine what types of data to collect 12 Steps for Establishing a Network Baseline • Step 2 Identify devices and ports of interest 13 Steps for Establishing a Network Baseline • Step 3 Determine the baseline duration It is... with surgical precision 18 A General Approach to Troubleshooting • The caveman: first instinct is to start swapping cards, cables, hardware, and software until miraculously the network begins operating again • Since both of these approaches are extremes, the better approach is somewhere in the middle using elements of both It is important to analyze the network as a whole rather than in a piecemeal fashion... Troubleshooting Methodologies and Tools 17 A General Approach to Troubleshooting • • • Network engineers, administrators, and support personnel realize that troubleshooting is a process that takes the greatest percentage their time Two extreme approaches to troubleshooting almost always result in disappointment, delay, or failure – The theorist, or rocket scientist, approach – The impractical, or caveman, . Chapter 8: Network Troubleshooting CCNA Exploration 4.0 2 Objectives • Establish and document a network baseline. • Describe the various troubleshooting methodologies and troubleshooting. called the network baseline. • Network documentation should include these components: – Network configuration table – End-system configuration table – Network topology diagram 5 Network configuration. workstations. 7 Network Topology Diagram • Graphical representation of a network, which illustrates how each device in a network is connected and its logical architecture. 8 Documenting Your Network 9 Network