System Message Guide for Cisco IOS XE 17.15.x

Overview of Cisco System Messages

This guide provides detailed information on system messages generated by Cisco software releases. These messages are sent to the console or a logging server during operation. While some messages are purely informational, others are critical for diagnosing issues with internal hardware, communications lines, or the system software itself.

How to Read System Error Messages

System error messages follow a structured format starting with a percent sign (%). The general structure is: %FACILITY-SUBFACILITY-SEVERITY-MNEMONIC: Message-text.

• FACILITY: Indicates the system module, protocol, or hardware device reporting the message.
• SEVERITY: A single-digit code (0-7) representing the urgency of the condition. Lower numbers indicate higher severity.
• MNEMONIC: A unique code identifying the specific error.
• Message-text: A descriptive string detailing the event, often containing variable fields in square brackets like [dec] for decimal numbers or [chars] for character strings.

Some messages include card and slot information, structured as: %CARD-SEVERITY-MSG:SLOT %FACILITY-SEVERITY-MNEMONIC: Message-text.

Error Message Severity Levels

Severity levels define the urgency of the message:

• 0 - Emergency: System unusable.
• 1 - Alert: Immediate action needed.
• 2 - Critical: Critical condition.
• 3 - Error: Error condition.
• 4 - Warning: Warning condition.
• 5 - Notification: Normal, but significant condition.
• 6 - Informational: Informational message only.
• 7 - Debugging: Appears during debugging only.

Troubleshooting and Support

When encountering error messages, review the provided recommendation actions. Some messages include traceback information, which is essential for technical support analysis. If a problem persists, collect the exact error message, relevant system logs, and output from show tech-support commands before contacting Cisco Technical Assistance Center (TAC).