Cisco Systems ASR 9000 Basic Troubleshooting Commands

6-2

Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide

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Chapter 6 Troubleshooting the Cisco IOS XR Software

Basic Troubleshooting Commands

Basic Troubleshooting Commands

The following sections describe some basic techniques used to determine connectivity to another device

and display information on the configuration and operation of a router.

• Using show Commands to Display System Status and Configuration, page 6-2

• Using the ping Command, page 6-2

• Using the traceroute Command, page 6-3

• Using debug Commands, page 6-3

Using show Commands to Display System Status and Configuration

Use show commands to check the status of various Cisco IOS XR software subsystems and services.

Table 5-2 lists some of the common show commands.

Using the ping Command

Use the ping command to diagnose network connectivity. In EXEC mode, enter a hostname or an IP

address as an argument to this command. In administration EXEC mode, you can use the fabric or the

control Ethernet network to ping other nodes.

The ping command sends an echo request packet to a destination, then awaits a reply. Ping output can

help you evaluate path-to-destination reliability, delays over the path, and whether the destination can

be reached or is functioning.

Each exclamation point (!) indicates receipt of a reply. A period (.) indicates the network server timed

out while waiting for a reply. Other characters may appear in the ping output display, depending on the

protocol type.

Examples

In the following example, a successful ping attempt is shown:

RP/0/RSP0/CPU0:router# ping 10.233.233.233

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.233.233.233, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/7 ms

In the next example, an unsuccessful ping attempt is shown:

RP/0/RSP0/CPU0:router# ping 10.1.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

Contents

Main Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide Page CONTENTS Page Page Page Page Page Preface Changes to This Document About This Document Intended Audience Organization of the Document Conventions Obtaining Documentation and Submitting a Service Request Page Introducing the Cisco ASR 9000 Series Aggregation Services Router Router Overview Features and Capabilities Cisco IOS XR Software Flexible Ethernet L2VPN Multicast OAM Layer 3 routing MPLS VPN QoS MPLS TE High Availability System Configurations 1-17 Management and Security Manageability Security Initial Router Configuration Management Interfaces Command-Line Interface Extensible Markup Language API Simple Network Management Protocol Connecting to the Router Through the Console Port Page Configuring Gigabit Ethernet and 10-Gigabit Ethernet Interfaces Page Bringing Up Cisco IOS XR Software on the Router Prerequisites Software Requirements Hardware Prerequisites and Documentation Bringing Up and Configuring the Router Page Verifying the System After Initial Boot Examples of show Commands show version Command: Example show platform Command: Example show redundancy Command: Example show environment Command: Example Page Configuring General Router Features Connecting to and Communicating with the Router Connecting Through the Console Port Connecting Through a Terminal Server Page Connecting Through the Management Ethernet Interface Logging In to a Router CLI Prompt User Access Privileges User Groups, Task Groups, and Task IDs Predefined User Groups Viewing Your User Groups and Task IDs 3-9 show user Command: Example To view your username, type the show user command: show user tasks Command: Example show user group Command: Example To view the user groups assigned to your user account, type the show user group command: Navigating Cisco IOS XR Software Command Modes Identifying the Command Mode in the CLI Prompt Common Command Modes Page Entering EXEC Commands from a Configuration Mode 3-15 Command Mode Navigation Example Note The commands available to you depend on the router mode and your user group assignments. The following steps provide an example of command mode navigation: Managing Configuration Sessions Entering Configuration Changes Page Viewing Active Configuration Sessions Starting a Configuration Session Simple RSP Configuration: Example Simple Administration Configuration Session: Example Starting an Exclusive Configuration Session Viewing Configuration Details Viewing the Running Configuration Viewing a Sanitized Version of the Running Configuration Viewing the Target Configuration Viewing a Combined Target and Running Configuration Viewing Configuration Error Messages and Descriptions Viewing Configuration Error Messages Without Descriptions Viewing Configuration Error Messages Produced While Loading a Configuration Saving the Target Configuration to a File Loading the Target Configuration from a File Loading an Alternative Configuration at System Startup Clearing All Changes to a Target Configuration Committing Changes to the Running Configuration Page Committing a Configuration from Global Configuration Mode: Example Committing a Configuration from Administration Configuration Mode: Example Reloading a Failed Configuration Exiting a Configuration Submode Returning Directly to Configuration Mode from a Submode Ending a Configuration Session Aborting a Configuration Session Configuring the RSP Hostname Configuring the Management Ethernet Interface Specifying the Management Ethernet Interface Name in CLI Commands Viewing the Available Management Ethernet Interfaces Configuring the Management Ethernet Interface Prerequisites Page Manually Setting the Router Clock Page Page Configuring Additional Router Features Configuring the Domain Name and Domain Name Server Page Configuring Telnet and XML Host Services Prerequisites Page Related Documents Managing Configuration History and Rollback Viewing CommitIDs Viewing Configuration Changes Recorded in a CommitID Previewing Rollback Configuration Changes Rolling Back the Configuration to a Specific Rollback Point Rolling Back the Configuration over a Specified Number of Commits Loading CommitID Configuration Changes to the Target Configuration Loading Rollback Configuration Changes to the Target Configuration Deleting CommitIDs Configuring Logging and Logging Correlation Logging Locations and Severity Levels Alarm Logging Correlation Configuring Basic Message Logging Page Disabling Console Logging Creating and Modifying User Accounts and User Groups Viewing Details About User Accounts, User Groups, and Task IDs Configuring User Accounts Creating Users and Assigning Groups Page Configuring Software Entitlement Configuration Limiting Static Route Configuration Limits IS-IS Configuration Limits OSPFv2 and v3 Configuration Limits 4-22 Maximum Interfaces for Each OSPF Instance: Example The following example configures the maximum interface limit on a router: Maximum Routes Redistributed into OSPF: Example Number of Parallel Links (max-paths): Example Routing Policy Language Line and Policy Limits 4-24 Multicast Configuration Limits MPLS Configuration Limits Other Configuration Limits CLI Tips, Techniques, and Shortcuts CLI Tips and Shortcuts Entering Abbreviated Commands Using the Question Mark (?) to Display On-Screen Command Help 5-3 configuration to the running configuration. that apply to the keyword and brief explanations: Step 3 Type t he deny option and a question mark to see more command options: Step 4 Type an IP address, followed by a space and a question mark (?), to list additional options: Completing a Partial Command with the Tab Key Identifying Command Syntax Errors Using the no Form of a Command Editing Command Lines that Wrap Viewing System Information with show Commands Common show Commands Browsing Display Output when the --More-- Prompt Appears Halting the Display of Screen Output Redirecting Output to a File Narrowing Output from Large Configurations Limiting show Command Output to a Specific Feature or Interface Using Wildcards to Display All Instances of an Interface Filtering show Command Output Adding a Filter at the --More-- Prompt Multipipe Support Show Parser Dump Enhancement Feature Wildcards, Templates, and Aliases Using Wildcards to Identify Interfaces in show Commands Example Creating Configuration Templates Page Applying Configuration Templates Aliases Keystrokes Used as Command Aliases Command History Viewing Previously Entered Commands Recalling Previously Entered Commands Recalling Deleted Entries Redisplaying the Command Line Key Combinations Key Combinations to Move the Cursor Keystrokes to Control Capitalization Keystrokes to Delete CLI Entries Transposing Mistyped Characters Troubleshooting the Cisco IOS XR Software Additional Sources for Information Basic Troubleshooting Commands Using show Commands to Display System Status and Configuration Using the ping Command Using the traceroute Command Using debug Commands Viewing a List of Debug Features Enabling Debugging for a Feature Viewing Debugging Status Disabling Debugging for a Service Disabling Debugging for All Services Started at the Active Terminal Session Disabling Debugging for All Services Started at All Terminal Sessions Configuration Error Messages Configuration Failures During a Commit Operation Memory Warnings in Configuration Sessions Understanding Low-Memory Warnings in Configuration Sessions WARNING! MEMORY IS IN MINOR STATE ERROR! MEMORY IS IN SEVERE (or CRITICAL) STATE Viewing System Memory Information Removing Configurations to Resolve Low-Memory Warnings Clearing a Target Configuration Removing Committed Configurations to Free System Memory Rolling Back to a Previously Committed Configuration Clearing Configuration Sessions Contacting TAC for Additional Assistance Interfaces Not Coming Up Verifying System Interfaces 6-13 Page 6-15 Step 7 Verify again that the interface is up by entering the show ipv4 interface brief command: Page APPENDIX A Understanding Regular Expressions, Special Characters, and Patterns Regular Expressions Special Characters Character Pattern Ranges Multiple-Character Patterns Complex Regular Expressions Using Multipliers Pattern Alternation Anchor Characters Underscore Wildcard Parentheses Used for Pattern Recall