Cisco IOS Software Releases 11.1

Field Notice: Cisco IOS Routed Protocol Defect (CSCdj31496)

Updated August 15, 1997

August 11, 1997

Products Affected

This field notice applies to all Cisco products that use any of the following Cisco IOS Releases:

  • Cisco IOS Interim Releases 11.0(16.1) through 11.0(16.2)

  • Cisco IOS Interim Releases 11.0(16.1)BT through 11.0(16.2)BT

  • Cisco IOS Interim Releases 11.1(12.4) through 11.1(13.3)

  • Cisco IOS Maintenance Release 11.1(13)

  • Cisco IOS Interim Releases 11.1(12.4)AA through 11.1(13.2)AA

  • Cisco IOS Maintenance Release 11.1(13)AA

  • Cisco IOS Interim Releases 11.1(12.5)CA through 11.1(13.1)CA

  • Cisco IOS Maintenance Release 11.1(13)CA

  • Cisco IOS Interim Releases 11.2(7.2) through 11.2(7.5)

  • Cisco IOS Interim Releases 11.2(7.2)P through 11.2(7.5)P

Note:? This defect does not impact the Distributed Director products in any 11.1(nn)IA releases.

Problem Description

A severe defect was discovered through Cisco Regression Analysis that affects all images for the releases listed below. The defects are unpredictable failures in all routed protocols.

Customer Impact

While the symptoms are unpredictable, the most common anomalies that customers have experienced are:

  • Inability to ping active devices

  • Routing updates not being sent through specific interfaces


There are two documented workarounds:

  • For IP, the console command clear ip route * temporarily clears related routing problems.

  • For all protocols, use shut ; no shut on all affected interfaces.

These fixes work only until another routing change is missed, so they are not recommended for customer environments, but only to verify that a particular symptom was probably caused by this defect.

As a result of this defect, all images associated with the Cisco IOS Releases noted above will be removed from CCO and locked under the appropriate DEFERRAL subdirectory on the /release server. Outstanding customer orders will be revised to deliver the latest version of Cisco IOS. A temporary fix, DDTs CSCdj31496 (registered customers only) , is available and integrated into releases 11.0(16.3) and 11.1(13.4).


To eliminate the problems mentioned in the above, Cisco strongly recommends that you download and install one of the Cisco IOS software release updates listed in Table 1.

Note:?The minimum Cisco IOS software recommendations in the table below supersede the Cisco IOS software information and recommendations stated in the installation and configuration publications that shipped with your Cisco IOS-based product.

Table 1: Cisco IOS Software Release Updates

Defect Found In:

Resolved In:

Available On CCO:

11.0(16.1) - 11.0(16.2)



11.0(16.1)BT - 11.0(16.2)BT



11.1(12.4) - 11.1(13.3)



11.1(12.4)AA - 11.1(13.2) AA



11.1(12.5)CA - 11.1(13.1)CA



11.2(7.2) - 11.2(7.5)



11.2(7.2)P - 11.2(7.5)P




While trying to resolve a high CPU utilization defect (CSCdi73194), code was modified to reduce the observed overhead of the IP BACKGROUND process. As a result, a number of routing changes are no longer dealt with correctly under certain conditions. Because the change was made to a routine used by all routed protocols (IP, IPX, AppleTalk, DecNet, VINES, XNS), it affects all products supporting any of these protocols. After this defect was introduced, the following reported bugs believed to be caused by this problem have been logged:

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




xns ping fail in fsip(x25) and hip(ppp)


routing protocols may not come up at boot for slower routers


IPX RIP updates not send over Ethernet interface


IPX routing fails for serial int with eigip & rip over PPP encap


IPX pings fail due to invalid cache entry


no ipx rip updates on fddi interface with snap encap

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:

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