Music on Hold Resources

The integrated Music on Hold (MoH) feature provides On-Net and Off-Net users with on hold music from a streaming source. The MoH feature has two hold types:

User hold A user presses the Hold button or Hold softkey .
Network hold A user activates the transfer, conference, or Call Park feature, which automatically activates the hold feature before performing the operation.

MoH is customizable so that it plays specific recordings, based on the DN that is used to place the caller on hold or the line number that the caller has dialed . Recorded audio or a live audio stream can be configured as audio sources.

The MoH feature requires the use of a server that is part of a Cisco CallManager cluster. You can configure the MoH server in either of the following ways:

Coresident deployment In a coresident deployment, the MoH feature runs on any server (either publisher or subscriber) in the cluster that is also running the Cisco CallManager software. Because MoH shares server resources with Cisco CallManager in a coresident configuration, this type of configuration drastically reduces the number of simultaneous streams that an MoH server can send.
Standalone deployment A standalone deployment places the MoH feature on a dedicated server within the Cisco CallManager cluster. The sole function of this dedicated server is to send MoH streams to devices within the network. A standalone deployment allows for the maximum number of streams from a single MoH server.

Table 15-7 provides details on the number of MoH sessions and codecs that are supported for each server platform.

Table 15-7. Transcoder Resource Capabilities

Server Platform

Codecs Supported

MoH Sessions Supported

Cisco MCS 7815

Cisco MCS 782 x (all models)

Cisco MCS 7830 (all models)

Cisco SPE-310

Hewlett-Packard DL320

IBM xSeries 33x (all models)

G.711 (a-law and mu-law)

G.729a

Wideband audio

Coresident server: 20 MoH sessions

Standalone MoH server: 50 MoH sessions

Cisco MCS 7835 (all models)

Cisco MCS 7845 (all models)

Hewlett-Packard DL380

IBM xSeries 34x (all models)

G.711 (a-law and mu-law)

G.729a

Wideband audio

Coresident server: 20 MoH sessions

Standalone MoH server: 250 MoH sessions

The maximum session limits apply to unicast, multicast, or simultaneous unicast and multicast sessions. The limits represent the recommended maximum sessions that a platform can support.

Creating Audio Source Files

Figure 15-6 shows the interactions among the audio translator, default MoH TFTP server, and MoH server. The large boxes in the figure represent cluster components that might reside on a single server or on three separate servers. This figure also shows how the MoH server processes the added audio source file.

Figure 15-6. Creating Audio Source Files

In creating an audio source, the following sequence takes place, as shown in the figure:

Step 1.

The network administrator drops the audio files into the C:\Program Files\Cisco\MoH\DropMoHAudioSourceFilesHere directory path . Standard .wav and MP3 files are valid input.

Note

It takes approximately 30 seconds to convert a 3-MB MP3 file.

Step 2.	Cisco CallManager automatically detects and translates the files.

Step 3.	The output and source files are moved into the default MoH TFTP server holding directory. This holding directory is the same as the default TFTPMoHFilePath with \MoH appended.

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Note

It is not recommended that the audio translator service be used during production hours because the service will consume 100 percent of the CPU.

Step 4.	The network administrator assigns an audio source number to the audio source file. The corresponding audio source files are then copied to a directory that is one level higher in the directory structure (which is the default TFTP path) to make them available to the MoH servers.
Step 5.	The MoH servers download the needed audio source files and store them in the hard-coded directory C:\Program Files\Cisco\MoH.
Step 6.	The MoH server then streams the files using DirectShow and the kernel-mode RTP driver as needed or requested by Cisco CallManager.

Configuring MoH

The Cisco CallManager MoH Configuration is a six-step process:

Step 1.	Configure the audio translator.
Step 2.	Configure the MoH server.
Step 3.	Add and configure audio source files.
Step 4.	Set MoH servicewide settings.
Step 5.	Find and configure the fixed audio source.
Step 6.	Assign audio source IDs.

Step 1: Configure the Audio Translator

An MoH audio translator service converts administrator-supplied audio sources to the proper format for the MoH server to use. The audio translator uses two parameters, an input directory and an output directory. You can configure the input directory, which defaults to:

C:\Program Files\Cisco\MoH\DropMoHAudioSourceFilesHere, on a per-service basis.

The output directory, a clusterwide parameter, contains a Universal Naming Convention (UNC) name to a shared directory on the default MoH TFTP directory. For whichever directory is specified, append \MoH.

To display the Service Parameters Configuration window, choose Service > Service Parameters in Cisco CallManager Administration, choose the server that will provide MoH (typically, the publisher if not a standalone server), and choose Cisco MoH Audio Translator for the service. Figure 15-7 illustrates this configuration.

Figure 15-7. Cisco MoH Audio Translator Service Configuration

After you configure the audio translator service, you can drop your MoH audio source files (in .wav or .mp3 format) into the drop directory you specify. As soon as you copy the files into the directory, the CallManager's audio translator service immediately goes to work converting the files into the various audio codecs compatible with the VoIP network.

Caution

Converting the audio source files into audio codec format can cause massive processor utilization on the CallManager server, potentially keeping it at 100 percent utilization for a short time (depending on the size and number of audio source files you copy). Cisco highly recommends doing this conversion during network off-hours.

Tip

Be sure to copy the MoH audio source files into the drop directory. If you move the files (by dragging and dropping them from a source on the same hard disk partition, such as the desktop), the files retain their original permissions rather than inheriting the permissions of the parent directory. If the permissions are not set correctly, the CallManager will not be able to convert the audio files.

Step 2: Configure the MoH Server

Figure 15-8 shows the MoH Server Configuration window. The MoH server can be configured for unicast or multicast. Multicast MoH conserves system resources. Multicast allows multiple users to use the same audio source stream to provide MoH. Multicast audio sources associate with an IP address. To use multicast audio for MoH, your network must be configured to support multicast traffic. In addition, the audio source is always playing. Users placed on hold will typically join the audio source midstream; if you have announcements that play at the beginning of the audio stream, they might be missed.

Figure 15-8. Cisco MoH Server Configuration

Unicast MoH, the system default, uses a separate source stream for each user or connection. Users connect to a specific device or stream. If your network supports multicast traffic, you can deploy MoH services much more efficiently . Cisco recommends using a locally scoped multicast address (239.x.x.x) to ensure MoH multicast traffic does not stream over the IP WAN unnecessarily.

Choose Service > Media Resource > Music On Hold Server to display the Music On Hold (MoH) Server Configuration window.

Step 3: Add and Configure Audio Source Files

The next step in configuring MoH is to add and configure the audio source files that the CallManager has converted (by adding .wav or .mp3 files to the directory shown in Step 1) to audio source IDs. Choose Service > Media Resource > Music On Hold Audio Source to display the Music On Hold (MoH) Audio Source Configuration window, shown in Figure 15-9.

Figure 15-9. Configuring Audio Source Files

To add audio source files, click the Add New MoH Audio Source link, choose an MoH Audio Stream Number unique in the cluster ( numbers range from 1 to 50), assign the MoH Audio Source File to the number, and click Insert . The Play Continuously (Repeat) check box should always be checked to ensure music loops when the end of the file is reached. If multicast capabilities are necessary, you must check the Allow Multicasting check box. If the Play Continuously (Repeat) and Allow Multicasting check boxes are both unchecked, the audio file stops playing when it reaches the end and the network administrator must stop and start the server to reset the MoH server.

The MoH Audio Source File Status window shows the conversion status and indicates whether the audio file translated correctly or had errors.

Step 4: Set MoH Servicewide Settings

To set the MoH servicewide settings, open the Service Parameters Configuration window, choose an MoH server, and choose the Cisco IP Voice Media Streaming App option. The Service Parameters Configuration window for MoH appears, as shown in Figure 15-10.

Figure 15-10. Voice Media Streaming Application Service Parameters

The Supported MoH Codecs field is set to the codecs that are supported by the MoH servers in the cluster. This field defaults to G.711 mu-law during the installation. You can enable multiple codecs by pressing the Ctrl key while selecting the codecs.

The Default TFTPMOH IP Address field is set to the IP address or computer name of the default MoH TFTP server.

Note

Compressed codecs (such as G.729) are designed to handle Latin-based speech patterns. Music on hold audio does not translate well through codecs of this nature and the degradation in music quality is very perceptible.

Step 5: Find and Configure the Fixed Audio Source

One of your options for MoH is a fixed music source (attached via a sound card). This could be an external CD player, jukebox, iPod, or any device that can connect through the Line In or Microphone port of your sound card. You will need the exact name (case sensitive) of the fixed audio source device to complete the fixed audio source configuration in Cisco CallManager.

Note

CallManager MCS servers do not ship with sound cards. A list of supported sound cards can be found in the CallManager SRND available at http://www.cisco.com/go/srnd.

To find the name of the fixed audio source, open Control Panel and choose Sounds and Multimedia . Choose the Audio tab. You can use any sound-recording device name that appears in the Preferred Device menu, shown in Figure 15-11. In addition, be sure to open the Recording Control window, and click the Volume button in the Sound Recoding area. Verify that the Line In, Microphone, or CD Audio check box is checked and the volume has been adjusted to an appropriate level (this might require some testing in your IPT environment).

Figure 15-11. Fixed Audio Source Windows Sound Properties

To allow Cisco CallManager to use the fixed audio source, you must link the CallManager configuration with the Windows sound device. After you have located the sound-recording device name that appears in the Windows Control Panel, you must open the Audio Source File Configuration window (by choosing Service > Media Resource > Music On Hold Audio Source ) and select the Fixed Audio Source (this will always be audio source ID 51). The window shown in Figure 15-12 appears.

Figure 15-12. Fixed Audio Source CallManager Configuration

The MoH Fixed Audio Source Device name is case sensitive and must be entered exactly as it appears in the Sounds and Multimedia Properties window, including any spaces or symbols that appear in the name. If the Allow Multicasting check box is checked, and the G.729 codec is enabled, 5 to 7 percent of the CPU resources will be consumed. This setting is global for all MoH servers. If the fixed audio source does not exist on a server, it cannot be used.

The Fixed Audio Source option affects all of the MoH servers that have an MoH fixed audio source device by the selected name.

Note

The FCC considers music on hold a type of broadcasting. Copyrighted music must be licensed for prerecorded and live audio sources. Failure to comply with this law can result in significant fines .

Step 6: Assigning Audio Source IDs

For your users to use the MoH sources you have configured, you must assign the audio source IDs to the IPT devices. An audio source ID represents an audio source on the MoH server. The audio source can be either a file on a disk or a fixed device from which a source stream obtains the streaming data. Each audio source (represented by an audio source ID) can stream in unicast and multicast mode.

The device that activates the hold will determine which audio source ID the caller will listen to. You can assign the MoH audio source IDs to a group of devices by assigning them through the device pool (choose System > Device Pool ), through the individual IP Phones (choose Device > Phone ), or for specific directory numbers (choose Device > Phone > Directory Number ). If you assign the audio sources at both the device pool and IP Phone levels, the IP Phone settings override the device pool. Likewise, the directory number assignments overrule both the IP Phone and device pool settings. Figure 15-13 illustrates assigning the audio source IDs at the IP Phone level.