Cisco Unified Communications Manager Express

Field Notice: Certain Uses of GUI Interface With Cisco CallManager Express and Cisco Unity Express May Cause Instability of Voice Gateway

November 23, 2004

Products Affected

  • CallManager Express

  • Unity Express

Problem Description

Use of Cisco CallManager Express (CCME) HTTP GUI interface may lead to IOS voice gateway corruption and instability, when certain commands are issued, such as configuring system wide parameters or resetting all IP phones. This can also occur with the GUI interface for Cisco Unity Express (CUE) when interworking with CCME. However, no customer reports or lab tests have found a problem with the use of the CCME or CUE GUI for individual ephone configuration or other end-user provisioning.


The CCME (and CUE when interworking with the CME) GUI interface was designed to ease the administration of the Cisco CallManager Express and Cisco Unity Express IOS features by allowing a graphical interface to the standard Cisco IOS CLI interface. The GUI translates and sends IOS CLI commands to the gateway via an HTTP communication path. Cisco engineering has determined that there are a limited set of commands (system wide configuration parameter and resetting of all IP phones) which can overwrite sections of gateway memory, thus leading to corrupted data on the voice gateway. Depending on the current IOS configuration and the particular command sent failures can range from minor to critical.

Problem Symptoms

A complete list of symptoms is not possible to define since the Cisco IOS configuration and type of command issued by the CCME/CUE GUI are customer specific.

One such configuration confirmed; When using a CISCO1760 with Cisco IOS® Software Release 12.3(8)T or 12.3(11)T, and digital T1/E1 module, using the CME GUI reset all phones command causes the T-1 slot information to become overwritten. A running config will show ok, but no changes to the T1 commands are allowed.

Other platforms are impacted by this issue as well but no deterministic effect has been seen in the field or lab to date.


Cisco is currently recommending customers with 1760 and T1 modules not to use the CME/CUE GUI interface until this defect is resolved in the Cisco IOS Image being used.

Customers who have been using CME/CUE GUI without problems may not see any problems. However, customers who have experienced router reloads or other stability issues without direct cause should consider disabling CME/CUE GUI until updating to the Cisco IOS version which resolves this issue. DDTS CSCeg03707.

Steps to take to avoid GUI Memory over-write of memory:

  1. Use the IOS/CUE CLI interface for configuring and maintaining a CCME VoIP gateway.

    To disable the CME GUI one of these two steps is advised:

  2. Remove the CME GUI files from flash.

  3. Disable HTTP access through the global configuration command no ip http server.


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CSCeg03707 (registered customers only)

Use of CME GUI interface leads to voice gateway instability

For More Information

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