Lecture CCNA Exploration 4.0 (Kỳ 4) - Chapter 8: Network Troubleshooting

In this chapter, you will learn to: 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.
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Lecture CCNA Exploration 4.0 (Kỳ 4) - Chapter 8: Network Troubleshooting Chapter 8 – Network Troubleshooting CCNA Exploration 4.0 1 Notation of the CCNA Voucher Học viện mạng Bach Khoa - Website: www.bkacad.com 2 • Testking CCNA 640-802 • Pass4sure • Testinside • Actualtest • Vnpro.org • Sadikhov.com • http://www.careercert.info • 9tut.net • Examcollection.com Học viện mạng Bach Khoa - Website: www.bkacad.com 3 Introduction Học viện mạng Bach Khoa - Website: www.bkacad.com 4 Establishing the Network Performance Baseline Học viện mạng Bach Khoa - Website: www.bkacad.com 5 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 and is captured in documentation such as configuration tables and topology diagrams. • Network documentation should include these components: 1.Network configuration table 2.End-system configuration table 3.Network topology diagram Học viện mạng Bach Khoa - Website: www.bkacad.com 6 Documenting Your Network 1. Network Configuration Table The data set that should be included for all components: – Type of device, model designation – IOS image name – Device network hostname – Location of the device (building, floor, room, rack, panel) – If it is a modular device, include all module types and in which module slot they are located – Data link layer addresses – Network layer addresses – Any additional important information about physical aspects of the device Học viện mạng Bach Khoa - Website: www.bkacad.com 7 Documenting Your Network 2. End-System Documentation The following information should be documented: – Device name (purpose) – Operating system and version – IP address – Subnet mask – Default gateway, DNS server, and WINS server addresses – Any high-bandwidth network applications that the end-system runs Học viện mạng Bach Khoa - Website: www.bkacad.com 8 Documenting Your Network 3. Network Topology Diagram At a minimum, the topology diagram should include: – Symbols for all devices and how they are connected – Interface types and numbers – IP addresses – Subnet masks Học viện mạng Bach Khoa - Website: www.bkacad.com 9 Network Documentation Process • Commands that are useful to the network documentation process include: – ping – telnet – show ip interface brief – show ip route – show cdp neighbor detail Học viện mạng Bach Khoa - Website: www.bkacad.com 10 Why is Establishing a Network Baseline Important ? • Establishing a network performance baseline requires collecting key performance data from the ports and devices that are essential to network operation. Học viện mạng Bach Khoa - Website: www.bkacad.com 11 Steps for Establishing a Network Baseline • Animation 8.1.4.1 • Step 1. Determine what types of data to collect Học viện mạng Bach Khoa - Website: www.bkacad.com 12 Steps for Establishing a Network Baseline • Step 2. Identify devices and ports of interest Devices and ports of interest include: – Network device ports that connect to other network devices – Servers – Key users – Anything else considered critical to operations. Học viện mạng Bach Khoa - Website: www.bkacad.com 13 Steps for Establishing a Network Baseline • Step 3. Determine the baseline duration It is important that the length of time and the baseline information being gathered are sufficient to establish a typical picture of the network. This period should be at least seven days to capture any daily or weekly trends. Weekly trends are just as important as daily or hourly trends. Học viện mạng Bach Khoa - Website: www.bkacad.com 14 Measuring Network Performance Data • Sophisticated network management software is often used to baseline large and complex networks. • For example, the Fluke Network SuperAgent module enables administrators to automatically create and review reports using its Intelligent Baselines feature. Học viện mạng Bach Khoa - Website: www.bkacad.com 15 Measuring Network Performance Data • In simpler networks, the baseline tasks may require a combination of manual data collection and simple network protocol inspectors. Học viện mạng Bach Khoa - Website: www.bkacad.com 16 Troubleshooting Methodologies and Tools Học viện mạng Bach Khoa - Website: www.bkacad.com 17 A General Approach to Troubleshooting • Two extreme approaches to troubleshooting almost always result in disappointment, delay, or failure. At one extreme is the theorist, or rocket scientist, approach. At the other extreme is the impractical, or caveman, approach. – The rocket scientist analyzes and reanalyzes the situation until the exact cause at the root of the problem has been identified and corrected with surgical precision. – The caveman's first instinct is to start swapping cards, cables, hardware, and software until miraculously the network begins operating again. Học viện mạng Bach Khoa - Website: www.bkacad.com 18 • Using Layered Models for Troubleshooting ...