Table Of Contents

Preface

Changes to This Document

Obtaining Documentation and Submitting a Service Request

Preface

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This guide describes how to troubleshooting a router using the Cisco IOS XR software.

This preface contains the following sections:

•Changes to This Document

•Obtaining Documentation and Submitting a Service Request

Changes to This Document

Table 1 lists the technical changes made to this document since it was first printed.

Table 1 Changes to This Document 

Revision	Date	Change Summary
OL-23591-02	April, 2011	Added details for the following topics: •Chapter 1, "General Troubleshooting Procedures"—Added information on prerequisite documentation for troubleshooting, Cisco-support task ID, show tech-support command, displaying ASIC errors, gathering logs and system information. Modified the information on diagnostics. •Divided interface troubleshooting into two separate chapters—Chapter 2 "Verifying and Troubleshooting Interface Status"and Chapter 3 "Troubleshooting Interface Connectivity." •Chapter 3 "Troubleshooting Interface Connectivity"—Added information on connectivity fault management (CFM). •Chapter 6 "Troubleshooting Layer 3 Connectivity"—Added information on CEF and interface accounting. •Chapter 7 "Troubleshooting Router Switch Fabric and Data Path"—Added information on NP counters. •Chapter 8 "Troubleshooting MPLS Services"—Corrected syntax of several commands. continued ...
OL-23591-02	April, 2011	... continued •Chapter 9 "Troubleshooting L2VPN and Ethernet Services"—Enhanced information about VLAN verification, included sample VLAN and PW configurations, added a section on Verifying MAC Address Updates, enhanced information about multipoint Layer 2 services (VPLS), moved information on DHCP snooping to this chapter, enhanced information on MST access gateways (MSTAGs). Reorganized the chapter for ease of use. •Chapter 10 "Troubleshooting Quality of Service and Access Control Lists"—Added information on queue conform and queue exceed counters displayed by the policy-map command. •Chapter 11 "Troubleshooting Multicast Services"—Reorganized this chapter to highlight IGMP snooping (Layer 2 MC) and native MC (Layer 3), and added information to each of these sections.
OL-23591-01	November 2010	(Initial release of this document as a multichapter book.) The content was reorganized for usability and updated to reflect Release 3.9 and 4.0 features.
OL-20794-01	December 2009	Initial release of this document as a single module.

Obtaining Documentation and Submitting a Service Request

For information on obtaining documentation, submitting a service request, and gathering additional information, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation, at:

http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html

Subscribe to the What's New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed and set content to be delivered directly to your desktop using a reader application. The RSS feeds are a free service and Cisco currently supports RSS version 2.0.