Catalyst 2950 and Catalyst 2955 Switch System Message Guide, 12.1(12c)EA1
System Message Overview
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System Message Overview

Table Of Contents

System Message Overview

How to Read System Messages

Error Message Traceback Reports

System Message Overview

This guide describes the Catalyst 2950-specific and Catalyst 2955-specific system messages. During operation, the system software sends these messages to the console (and, optionally, to a logging server on another system). Not all system messages indicate problems with your system. Some messages are purely informational, whereas others can help diagnose problems with communications lines, internal hardware, or the system software. This guide also includes error messages that appear when the system fails.

This chapter contains these sections:

How to Read System Messages

Error Message Traceback Reports

Note This software release does not support the Catalyst 2950 LRE switches. For information about these switches, refer to the Catalyst 2950 LRE switch release notes.

How to Read System Messages

System messages begin with a percent sign (%) and are structured as follows:


FACILITY is a code consisting of two or more uppercase letters that show the facility to which the message refers. A facility can be a hardware device, a protocol, or a module of the system software. Table 1-1 lists the system facility codes.

Table 1-1 Facility Codes 

Facility Code


Cluster Membership Protocol

"CMP Messages" section


802.1X authentication

"DOT1X Messages" section


Dynamic Trunking Protocol

"DTP Messages" section



"EC Messages" section



"ENVIRONMENT Messages" section


Ethernet controller

"ETHCNTR Messages" section


Gigabit Interface Converter (GBIC) module identification and validation

"GBIC Messages" section


GBIC module security

"GBIC_SECURITY Messages" section


GigaStack GBIC module

"GIGASTACK Messages" section


Hardware MAC address table manager

"HWMATM_MOD Messages" section


Fast Ethernet link-specific messages

"LINK_3 Messages" section


Application-specific integrated circuit (ASIC) for Catalyst 2950 switches.

"PLATFORM_CAT2950 Messages" section


Low-level platform

"PLATFORM_CATALYST2950 Messages" section


Application-specific integrated circuit (ASIC) for Catalyst 2955 switches.

"PLATFORM_CATALYST2955 Messages" section


Port manager

"PM Messages" section


Port security

"PORT SECURITY Messages" section


Switched Port Analyzer (SPAN)

"SPAN Messages" section


Spanning tree

"SPANTREE Messages" section


Spanning-tree fast convergence

"SPANTREE_FAST Messages" section


Spanning-tree VLAN switch

"SPANTREE_VLAN_SWITCH Messages" section


Storm control

"STORM_CONTROL Messages" section


VLAN manager

"SW_VLAN Messages" section


UniDirectional Link Detection (UDLD)

"UDLD Messages" section


UplinkFast multicast software

"UFAST_MCAST_SW Messages" section

SEVERITY is a single-digit code from 0 to 7 that reflects the severity of the condition. The lower the number, the more serious the situation. Table 1-2 lists the message severity levels.

MNEMONIC is a code that uniquely identifies the message.

Table 1-2 Message Severity Levels 

Severity Level

0 - emergency

System is unusable.

1 - alert

Immediate action required.

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

Message that appears during debugging only.

Message-text is a text string describing the condition. This portion of the message sometimes contains detailed information about the event, including terminal port numbers, network addresses, or addresses that correspond to locations in the system memory address space. Because the information in these variable fields changes from message to message, it is represented here by short strings enclosed in square brackets ([ ]). A decimal number, for example, is represented as [dec]. Table 1-3 lists the variable fields in messages.

Table 1-3 Representation of Variable Fields in Messages 

Type of Information


Decimal integer


Single character


Character string


Ethernet address (for example, 0000.FEED.00C0)


Hexadecimal integer


Internet address

This is a sample system message:

%EC-5-UNBUNDLE:Interface Gi0/9 left the port-channel Po2

The messages in "Message and Recovery Procedures," are described in alphabetical order by facility code with the most severe (lowest number) errors described first.

Error Message Traceback Reports

Some messages describe internal errors and contain traceback information. This information is very important and should be included when you report a problem to your technical support representative.

This sample message includes traceback information:

-Process= "Exec", level= 0, pid= 17
-Traceback= 1A82 1AB4 6378 A072 1054 1860