IP Application Services

Document ID: 20755

Contents

Introduction
Prerequisites
      Requirements
      Components Used
      Conventions
Problem
Solution
      Workaround
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Related Information

Introduction

This document provides information about SNMP-3-TRAPBLOCK messages observed on Cisco IOS® devices when DLSw traps are enabled. For more information, refer to Cisco bug ID CSCdm90577 ( registered customers only) .

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

For more information on document conventions, refer to the Cisco Technical Tips Conventions.

Problem

When a router is configured to send traps for DLSW, either of the following messages may appear along with a traceback when a trap is sent for peer changes:

Jan 19 01:47:29: %SNMP-3-TRAPBLOCK: Attempt to generate SNMP trap from a process with blocking disabled 

Jun  8 08:15:11.033: %SYS-2-NOBLOCK: idle with blocking disabled 

All hardware is affected, and all DLSw and SNMP implementations in Cisco IOS Software Releases 11.3 through 12.0T are affected.

Depending on the Cisco IOS version in use, the above messages may or may not be logged. The problem stems from a timing issue where the SNMP trap write operation exceeds the time that the DLSW process waits. The result is a traceback indication in the router log. A portion of a sample traceback appears below:

60962298[snmp_trap+0xa0] 
60D3FED4[cdeTrapCircuitUpDown+0x1a8] 
60C9229C[dlsw_action_k+0xdc] 
60FDD5F4[fsm_execute+0xf4] 
60C93814[dlsw_fsm+0x6c4] 
60C8F77C[dlsw_pre_proc_ssp+0x568] 
60C8F8B8[peer_to_core+0x70] 
60C778C0[peer_input+0xb88] 
60C7FAFC[dlsw_tcpd_readf+0x420] 
606407E0[tcpdriver_input+0xb8] 
6057DAA8[tcp_qsegment+0x610] 
6057F90C[tcp_inputsegment+0x183c] 
605B89BC[ipv4_tcp_input+0x134] 

Solution

The bug fix is integrated into Cisco IOS Software Release 12.1(0.1), so Cisco IOS Software Release 12.1 or later do not exhibit this problem.

Workaround

Since these messages do not affect the operation of the router, except for not delivering the trap, no workaround is necessary. However, you can issue the following global configuration command to disable the appropriate SNMP traps and eliminate the console messages:

no snmp-server enable traps dlsw

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Related Information

• Cisco IOS SNMP Traps Supported and How to Configure Them
• IP Application Services Tech Notes
• Technical Support - Cisco Systems