Cisco 12000 Series Routers

Field Notice: Problems Upgrading and Downgrading from IOS Release 12.0(27)S1 on Cisco 12000 Secondary PRP

May 18, 2004

Products Affected




Cisco 12000 12.0(27)S1 Service Provider Image for PRP

Problem Description

When upgrading or downgrading IOS from a system currently running 12.0(27)S1 on PRPs in a Cisco 12000, the secondary PRP never leaves the STRTSTBY state and eventually reboots. The secondary PRP will continue to reboot until the router is reloaded.


This problem only happens when a Cisco 12000 currently running 12.0(27)S1 on the secondary PRP, in a dual PRP system, attempts to reload to a different IOS image.

The following IOS CLI strings can be used to verify this problem.

show redundancy all will indicate:

b2#sh red all

          Active PRP in slot 10: substate = p_redundant

          Standby PRP in slot 9: Choice of active due to arbitration judgement from slot 
          9 PRP has larger memory

          Preferred PRP: none

          Operating Redundancy Mode: RPR [standby 
          initialization in progress]

The error log will indicate:

b2# SEC 9:00:01:11: %SYS-5-RELOAD: Reload requested Reload Reason: No response from Active. 

          Apr 26 16:49:32: %MBUS-6-DEADSCDY: Standby RP in slot 9 timed out, reset.

Problem Symptoms

In a dual PRP Cisco 12000 router, the secondary PRP is stuck in STRTSTBY state and continuously reloads after upgrading from 12.0(27)S1 to a different IOS image.


The only workaround for this problem is to reload the entire router.

Warning: Do not use fast software upgrade capabilities when you reload the entire router.

This problem has been fixed in IOS releases 12.0(28)S and will be fixed in 12.0(27)S2.


To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.



CSCee39574 (registered customers only)

Standby RP stuck in STRTSTBY leading to continuous Standby RP reloading after IOS upgrade from 12.0(27)S1.

CSCed56092 (registered customers only)

Standby RP keep resetting when downgrading from 12.0(27)S1.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

Receive Email Notification For New Field Notices

Product Alert Tool - Set up a profile to receive email updates about reliability, safety, network security, and end-of-sale issues for the Cisco products you specify.