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Cisco Unified IP Phone 7900 Series

Field Notice: FN - 62506 - 7920 Locks Up After Receiving Inter-Access Point Protocol Response Packet From Cisco Aironet Access Points Controlled by Wireless LAN Controller Software Releases 4.0.155.0, 4.0.155.1, or 4.0.179.8 and Later Releases of 4.0


Revised September 1, 2006

August 30, 2006

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

Hardware ID

CP-7920-AP-K9

CP-7920-AU-K9

CP-7920-ET-K9

CP-7920-FC-K9

CP-7920-JA-K9

CP-7920G-AU-K9

Problem Description

CP-7920 Wireless IP Phones can become unstable when associated to Access Points (APs) being controlled by Wireless LAN Controller (WLC) release 4.0.155.0, 4.0.155.5, or 4.0.179.8 and later releases of WLC 4.0.

This anomaly does not occur when the APs are being controlled by Wireless LAN Controller release 3.2.

Background

WLC release 4.0.155.0 introduced Cisco Compatible eXtensions (CCX), a set of features providing for enhanced wireless services. CCX provides for the wireless client to query the access point for a list of adjacent neighboring APs, using a packet format called Inter-Access Point Protocol (IAPP). When the WLC-controlled AP responds to the CP-7920 with a list that includes 802.11a radios, the CP-7920 may malfunction.

Problem Symptoms

CP-7920s may become unstable, or reboot, or become unusable.

Workaround/Solution

Workaround 1:

Disabling the 802.11a radios on the access points may prevent the problem with the CP-7920s from occuring.

Workaround 2:

Downgrade WLC to version 3.2. Be aware that, upon downgrading a WLC from a 4.0 to a 3.2 release, the configuration will be lost and will need to be manually re-entered.

Solution:

Contact Cisco TAC for a special 3.0-based build of CP-7920 code that contains fixes for CSCsf04685 and CSCsf06405. A standard release, posted to cisco.com, with these fixes, 3.0(1), is planned for September 2006.

Note that the use of special releases should be temporary. Cisco recommends using the latest available release of firmware.

Recovery:

If the CP-7920 becomes unusable, remove the battery, wait 30 seconds, and reinstall the battery.

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

CSCsf04685 (registered customers only)

7920 may become non-responsive when receiving many beacons

CSCsf06405 (registered customers only)

7920 is locking up after receiving IAPP response packet from Airespace

Revision History

Revision

Date

Comment

1.1

01-SEP-2006

Added info on 4.0.179.8 and later being affected

1.0

30-AUG-2006

Initial Public Release

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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