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Cisco IOS Software Releases 12.4 T

Field Notice: FN - 62854 - Cisco IOS - Performance Degradation and Reloads Possible When Using Quality of Service Features in Version 12.4(11)T


Revised August 31, 2007

July 26, 2007

NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


Products Affected

Product

Comments

12.4T - 12.4(11)T

All rebuilds of 12.4(11)T are affected

Problem Description

One or more operational problems may occur in Cisco IOS release 12.4(11)T when Quality of Service (QoS) features are configured. Users may observe incorrect packet accounting values, reduced packet forwarding performance, and in some cases IOS reboots

Background

Cisco IOS release 12.4(11)T introduced an enhanced packet classification infrastructure. This new infrastructure provides a single flexible packet classification system for Cisco IOS. After the new infrastructure was introduced, several new software bugs were discovered that were not observed with the old packet classification infrastructure. A subset of those bugs appears for reference in this notice. .

Problem Symptoms

One of several symptoms may be observed including counters that indicate incorrectly classified packets, packet forwarding performance degradation, and forced reboot of the entire IOS system. These symptoms are possible on any hardware platform supported by version 12.4(11)T. All rebuilds of Cisco IOS release 12.4(11)T are affected (e.g. 12.4(11)T1, 12.4(11)T2, ...).

These symptoms are possible on any hardware platform supported by version 12.4(11)T. All rebuilds of Cisco IOS release 12.4(11)T are affected (e.g. 12.4(11)T1, 12.4(11)T2, ...).

Workaround/Solution

There is no workaround that avoids all possible symptoms.

A solution is expected to be available in Cisco IOS version 12.4(15)T1 and later.

To avoid the symptoms, users may downgrade to a pre-12.4(11)T release or upgrade to 12.4(15)T1 or 12.4(15)T2 when it becomes available.

Cisco strongly discourages deploying an IOS 12.4(11)T release with QoS features enabled due to the potential severity of symptoms.

DDTS

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

DDTS

Description

CSCek72110 (registered customers only)

CCE Data-Plane Optimizations

CSCsh34327 (registered customers only)

Classification fails after Router reload

CSCsi03751 (registered customers only)

Wrong counters in sh policy-map int when child policy re-used

CSCsj34699 (registered customers only)

Router crashes when using QoS and traffic shaping

CSCsg31867 (registered customers only)

Router crashes on large ping pkts with IPSEC/NAT configured

Revision History

Revision

Date

Comment

1.0

26-JUL-2007

Initial Public Release

1.1

29-AUG-2007

Revised to remove CCE & ammend test on solution releases.

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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