Cisco Unified Videoconferencing 3500 Series Products

Field Notice: Random Reboots of MCUs and Gateways in Cisco IP/VC 3500 Series

October 9, 2000

Products Affected




Version 2.1


Version 2.0


Version 2.0


Version 2.0


Version 2.0


Version 2.0


Version 2.0

Problem Description

Cisco IP/VC 3510 Multipoint Control Units (MCUs) and Cisco IP/VC 3520 and 3525 gateways that are running software versions 2.0 or 2.1 can lock up in a continuous loop from which they cannot recover if the embedded Gatekeeper is disabled.


Cisco IP/VC 3510 MCUs and Cisco IP/VC 3520 and 3525 gateways include an embedded Gatekeeper that is disabled when the unit ships from the factory. Users can enable the embedded Gatekeeper to perform H.323 gatekeeping functions in their video conferencing environment. For MCUs with version 2.1 software and gateways with version 2.0 software, the unit can lock in a continuous loop when the embedded Gatekeeper is disabled (the default state).

MCUs and gateways do not lock in a continuous loop when the embedded Gatekeeper is enabled.

This bug occurs due to partial initialization of the Gatekeeper when it is disabled. The Gatekeeper is not initialized at all by a MCU that is configured as "MP Dedicated."

This software bug requires an updated configuration to shipping products which can be downloaded for current field units.

Problem Symptoms

One symptom of this software bug is random and/or continuous reboots of the Cisco IP/VC 3520 and 3525 gateway or MCU. Another symptom is improper booting or failing of the device after a short period. This problem affects all Cisco IP/VC 3500 series products running software version 2.0 or later.

The problem may occur in units shipped with software versions 2.0 or 2.1, and in earlier units after an upgrade to software version 2.1.


The workaround, a change to the configuration, allows users who do not want to use the embedded Gatekeeper for gatekeeping functions to enable it in passive mode. This means that the Gatekeeper is turned on, but that it has no effect on the device, which still has the ability to be registered with an external Gatekeeper.

If you are using the built-in Gatekeeper as your local Gatekeeper, then you must ensure that it remains enabled at all times. If you are not using the built-in Gatekeeper, follow the procedure below to enable the Gatekeeper in passive mode. The Gatekeeper continues to operate without accepting registrations and without influencing other devices in your system.

To enable the built-in Gatekeeper in passive mode:

  1. Start the Cisco IP/VC configuration utility.

  2. In the Configuration Source screen, select Gatekeeper Setup. The Gatekeeper Application Parameters screen is displayed.

  3. In the Application Parameters screen, select Network Control. The Network Control screen is displayed.

    The Network Control screen is displayed.

  4. In the Network Control screen, check the GK On checkbox to enable the Gatekeeper.

  5. Uncheck the Accept Registration and the Accept Calls checkboxes.

  6. Set the Discovery Multicast Address port number to 65013.

  7. Click OK, and then exit the configuration interface.

This bug is corrected in the next release of the Cisco IP/VC software, version 2.2, and the configuration change is not required. The First Commercial Shipment (FCS) is scheduled for December 2000.


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




Random Reboots of MCU and Gateways Running Upgraded 2.1 Software.

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: