Cisco IOS Software Releases 12.0 S

Field Notice: OSPF i-SPF Feature May Cause IOS to Reload

November 22, 2004

Products Affected



12.0(24)S -

12.0(24)S thru 12.0(29)S affected

12.2(18)S -

12.2(18)S thru 12.2(25)S

12.3(2)T -

12.3(2)T thru 12.3(11)T affected

Problem Description

A defect in the Incremental Shortest Path First (I-SPF) feature can cause Cisco IOS to restart, resulting in complete service interruption on the affected device.


A defect was introduced with the I-SPF feature that can cause devices running Cisco IOS to reload if they are running OSPF routing protocol with I-SPF enabled. This defect can cause multiple device reloads in redundant network topologies and has the potential to cause significant service impacting outages.

Problem Symptoms

Cisco IOS may erroneously omit routes from the routing table or fail to remove routes correctly. Cisco IOS may also reload unexpectedly with a "watchdog timeout" bus error exception.


Customers running an affected Cisco IOS release are strongly recommended to disable the I-SPF feature using the configuration commands

router ospf process-id
 no ispf

or upgrade to a release that has the fix. A fix is available in the latest Cisco IOS releases supporting I-SPF. Registered users may find a current list of fixed releases by searching on defect number CSCec22723 in Bug Toolkit.


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



CSCec22723 (registered customers only)


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.