Cisco Unified Communications Manager (CallManager)

Document ID: 50345

Contents

Introduction
Prerequisites
      Requirements
      Components Used
      Conventions
How to View and Understand CAST Traces
      View the CAST Trace
      The CAST Viewer Dialog Box
      Understand CAST Messages
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Related Information

Introduction

If your initial efforts to troubleshoot are not successful, you could be required to use traces. This allows you to analyze what component has failed with Cisco VT Advantage. This document discusses the use of trace tools provided with Cisco VT Advantage and how to understand them.

Prerequisites

Requirements

Readers of this document should have knowledge of these topics:

• A comfortable understanding of how to read and interpret trace output from the Cisco CallManager and Cisco VT Advantage

Components Used

The information in this document is based on these software and hardware versions:

• Cisco VT Advantage used with Microsoft Windows 2000 and Windows XP

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

For more information on document conventions, refer to the Cisco Technical Tips Conventions.

How to View and Understand CAST Traces

These sections provide information to help you view and interpret CAST traces.

View the CAST Trace

From the Start menu, open the Cisco VT Advantage Diagnostics window. As shown in Figure 1, there are three buttons, labeled Update Status, CDP Viewer, and CAST Viewer, at roughly 6:00 in this dialog box:

The CAST Viewer Dialog Box

If you press the CAST Viewer button, a dialog box appears. You can use this box in order to view what Cisco CallManager sends. Figure 2 is an example of the CAST Viewer dialog box you see.

• On the right-hand side of the dialog box, you see a list of messages that are exchanged between Cisco VT Advantage and the Cisco CallManager. If you use your mouse in order to select one of the messages, the detail in the Message Breakdown window expands on the right-hand side as well (see Figure 3).

  Note: There are a series of messages, all around 12:52. There is a long series of call status messages that are sent while the call is set up. These let Cisco VT Advantage know what state the phone is in at any given time.

  Note: Although these messages provide additional information, all you really need to examine is the message highlighted in Figure 2. The OpenMultiMediaReceiveChannel message is sent by the Cisco CallManager in order to indicate that a video stream is going to be sent to the PC.

• If you see the OpenMultiMediaReceiveChannel message, a corresponding acknowledgment sent by Cisco VT Advantage is visible. If you do not see this message, no video was sent and none is expected.

• The Cisco CallManager also sends a command that tells Cisco VT Advantage to send video. This comes in the form of a StartMultimediaTransmission message, which tells Cisco VT Advantage to begin video transmission. Without this message, no video is sent.

• You can bring up the CAST Viewer dialog box at any time, and this dialog box shows you a trace of the messages that were sent during your call. You can also save the contents of the message buffer to a file for later analysis or in order to help Cisco Technical Support troubleshoot your video issues.

Understand CAST Messages

If video was not enabled with your call, look at the CAST Viewer first. This example has a sequence of station information messages, but no commands to send or receive multimedia data. What does a message buffer, such as the one in Figure 3, mean?

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Related Information

• Voice Technology Support
• Voice and IP Communications Product Support
• Recommended Reading: Troubleshooting Cisco IP Telephony
• Technical Support - Cisco Systems