© 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Course v6 Chapter # 1 Chapter 2: Troubleshooting Processes for Complex Enterprise Networks CCNP TSHOOT: Maintaining and Troubleshooting IP Networks

Chapter # 2 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Chapter 2 Objectives  Identify troubleshooting principles and evaluate troubleshooting methodologies.  Plan and implement troubleshooting procedures as part of a structured troubleshooting methodology.  Plan and implement troubleshooting and network maintenance procedures to effectively support each other.

Chapter # 3 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Troubleshooting Methodologies Flow chart of a structured troubleshooting approach

Chapter # 4 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Troubleshooting Methodologies Shoot from the hip vs. structured troubleshooting method

Chapter # 5 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Troubleshooting Approaches  Top-down  Bottom-up  Divide and conquer  Follow-the-path  Spot the differences  Move the problem

Chapter # 6 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Troubleshooting Approaches - Spot the Differences Example  Branch1 is in good working order  Branch2 has connectivity problems Branch2# show ip route /24 is subnetted, 1 subnets C is directly connected, FastEthernet4 C /24 is directly connected, BVI1 Branch1# show ip route /24 is subnetted, 1 subnets C is directly connected, FastEthernet4 C /24 is directly connected, BVI1 S* /0 [254/0] via

Chapter # 7 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Troubleshooting Approaches - Move the Problem Example Laptop B is having network problems. Cable or port swapping can help isolate the problem.

Chapter # 8 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Implementing Troubleshooting Procedures  Defining the problem  Gathering information  Analyzing the information  Eliminating possible problem causes  Formulating a hypothesis about the likely cause of the problem  Testing that hypothesis  Solving the problem

Chapter # 9 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting Process – Verify and Define the Problem

Chapter # 10 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting Process – Gather Information

Chapter # 11 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting Process – Analyze

Chapter # 12 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting Process – Eliminate

Chapter # 13 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting Process – Propose Hypothesis

Chapter # 14 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting Process – Test Hypothesis

Chapter # 15 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting Process – Solve Problem

Chapter # 16 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting and Network Maintenance

Chapter # 17 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public The Troubleshooting and Network Maintenance – Cont.  Accurate documentation is critical to effective troubleshooting.  A network baseline is essential and can include: Interface load for critical network links (IOS) CPU load and memory usage of routers and switches (SNMP) Accounting of network traffic (NBAR, NetFlow) Measurement of network performance characteristics (IP SLA)

Chapter # 18 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Communication and Change Control Communication plays a role in all phases of structured troubleshooting.

Chapter # 19 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Communication and Change Control – Cont.  Change control is a fundamental process in network maintenance.  Controls when changes are made, authorization required and what actions are taken.  Can reduce unplanned outages and increase network uptime.  The change control process: Implement the change Verify that it achieved the desired results Roll back if necessary Back up the changed configurations or software Document/communicate your changes

Chapter # 20 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Disaster Recovery Tools  Successful disaster recovery is dependent on the existence of the following: Up to date configuration backups Up to date software backups Up to date hardware inventories and documentation Configuration and software provisioning tools

Chapter # 21 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Chapter 2 Summary  The fundamental elements of a troubleshooting process: Gathering of information and symptoms Analyzing information Eliminating possible causes Formulating a hypothesis Testing the hypothesis  Some commonly used troubleshooting approaches are: Top-down Bottom-up Divide-and-conquer Follow-the-path Spot the differences Move the problem

Chapter # 22 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public Chapter 2 Summary – Cont.  Useful data to gather and create a network baseline are: Basic performance statistics using show commands Accounting of network traffic using RMON, NBAR, or NetFlow statistics Measurements of network performance characteristics using the IP SLA feature in IOS  Communication is an essential part of the troubleshooting process and happens in all stages of troubleshooting: Report the problem Gather information Analyze and eliminate possible causes Propose and test a hypothesis Solve the problem  Change control is one of the most fundamental processes in network maintenance.

Chapter # 23 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public  There are no labs for this chapter. Chapter 2 Labs

Chapter # 24 © 2007 – 2010, Cisco Systems, Inc. All rights reserved. Cisco Public