Cisco Systems OL-4660-01 User Manual

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Cisco Call Back

The Cisco Call Back feature allows you to receive call back notification on your
Cisco IP Phone when a called party line becomes available. To receive call back
notification, a user presses the CallBack softkey while receiving a busy or
ringback tone. You can activate call back notification on a line on a
Cisco IP Phone within the same Cisco CallManager cluster as your phone. You
cannot activate call back notification if the called party has forwarded all calls to
another extension.

This chapter provides the following information about Cisco Call Back:

• Introducing Cisco Call Back, page 4-2

• System Requirements for Cisco Call Back, page 4-8

• Interactions and Restrictions, page 4-9

• Installing and Activating Cisco Extended Functions for the Cisco Call Back

Feature, page 4-10

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• Configuring Cisco Call Back Feature, page 4-11

• Providing Information to Users for Cisco Call Back Feature, page 4-16

• Troubleshooting Cisco Call Back Feature, page 4-16

• Where to Find More Information, page 4-16

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Introducing Cisco Call Back

Introducing Cisco Call Back

The following sections provide information about the Cisco Call Back feature:

• Overview of Cisco Call Back Architecture, page 4-2

• Cisco Extended Functions Service Dependency, page 4-5

• Multiple Cisco Extended Functions Applications in a Cluster, page 4-6

• How to Use Cisco Call Back, page 4-7

Overview of Cisco Call Back Architecture

The Cisco Call Back feature uses the Cisco Extended Functions (CEF) service.
The CEF service comprises the following interfaces:

• Cisco CTIManager Interface (QBEHelper), page 4-3

• Cisco CallManager Database Interface (DBL Library), page 4-3

• Call Back Handler, page 4-4

• Screen Saver and Call Back Dictionary, page 4-4

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4-2

• Redundancy Manager, page 4-4

• DB Change Notifier, page 4-4

• SDI Trace and Alarm, page 4-5

The CEF service interfaces with the phone by using the XML services interface
(XSI) over skinny protocol (a protocol that is used between a Cisco IP Phone and
Cisco CallManager) and the Quick Byte Encoding protocol (a protocol that is
used between the Cisco CTIManager and TSP/JTAPI). See Figure 4-1.

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Chapter 4 Cisco Call Back

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Introducing Cisco Call Back

Figure 4-1 Cisco Call Back Using the Cisco Extended Functions Service

Architecture

Skinny

NT Service Cisco Extended Functions

Redundancy manager

M

XSI over
skinny

QBE

Cisco
CallManager

Call Back Handler

DB Change Notification handler

Screen Saver

Call Back
Dictionary

QBEHelper DBL Library

Cisco
CTIManager

DB (SQL & Directory)

Cisco CTIManager Interface (QBEHelper)

The QBEHelper library provides the interface that allows the CEF service to
communicate with a configured Cisco CTIManager.

Cisco CallManager Database Interface (DBL Library)

The DBL library provides the interface that allows the CEF service to perform
queries on various devices that are configured and registered in the
Cisco CallManager database.

SDI Trace Alarm

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Introducing Cisco Call Back

Call Back Handler

The Call Back Handler resides in the CEF service and receives the called
extension and calling extension information when the CallBack softkey is
pressed. Cisco CallManager passes this information to the CEF service through
the Cisco CTIManager interface.

The Cisco Extended Functions service determines the destination device by using
the Cisco CallManager Database Interface. The CEF service opens the line and
device by using Cisco CTIManager. When the called line becomes available, the
CEF service sends an audio alert (a twinkle sound) and visual notification on the
Cisco IP Phone through the Cisco CTIManager and XSI interfaces. Only one Call
Back can be active on a Cisco IP Phone. The Call Back Handler keeps this
information in memory. Phones and lines get opened through Cisco CTIManager
only for a Call Back-activated phone and called phone line. When the Call Back
notification goes to the Call Back-activated phone, the phone and lines that were
opened by Cisco CTIManager close.

Screen Saver and Call Back Dictionary

Chapter 4 Cisco Call Back

The screen saver of the Cisco Extended Functions service reads the XML
dictionary files and creates Document Object Model (DOM) objects for all
installed locales when the CEF service starts. The system uses these DOM objects
for constructing XSI screens that are needed by the Cisco IP Phone.

Redundancy Manager

When multiple Cisco Extended Functions are active within a Cisco CallManager
cluster, the redundancy manager uses an algorithm to determine which CEF is
active and which is the backup CEF. The Redundancy Manager uses the lowest IP
address of the server that is running the CEF service as the active service. The
remaining CEF services serve as backup services.

DB Change Notifier

The DB Change Notifier handles all the database change notifications, such as
service parameter changes, trace parameter changes, and alarm configuration
changes, and reports the changes to the CEF service.

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Chapter 4 Cisco Call Back

SDI Trace and Alarm

The Cisco Extended Functions service uses the SDI Trace and Alarm libraries.
The libraries generate trace and alarms to the Event Viewer. The alarm library
publishes information to the Cisco RIS Data Collector service about the CEF
service. For more information about trace and alarms, refer to the
Cisco CallManager Serviceability Administration Guide.

Cisco Extended Functions Service Dependency

Cisco Call Back uses the Cisco Extended Functions service, which depends on the
following services (see Figure 4-2):

• Cisco CallManager—Ensure a minimum of one Cisco CallManager service

is running in the cluster, but the service need not be on the same server as
CEF.

• Cisco CTIManager—Ensure a minimum of one Cisco CTIManager service is

running in the cluster, but the service need not be on the same server as CEF.

• Cisco Database Layer Monitor—Ensure one Cisco Database Layer Monitor

service is running on the same server as CEF.

Introducing Cisco Call Back

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• Cisco RIS Data Collector—Ensure one Cisco RIS Data Collector service is

running on the same server as CEF.

Tip Install all the services on one server for one-server Cisco CallManager systems.

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Chapter 4 Cisco Call Back

Introducing Cisco Call Back

Figure 4-2 Cisco Extended Functions Service Dependency (Typical

Configuration)

Cisco

CallManager

Cisco

CTIManager

Cisco

CallManager

Cisco

CTIManager

Cisco

CallManager

Cisco
Extended
Functions

(Active)

Cisco
Extended
Functions

(Backup)

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Multiple Cisco Extended Functions Applications in a Cluster

If multiple Cisco Extended Functions applications are active within a
Cisco CallManager cluster, Cisco Extended Functions uses an algorithm to
determine which application should be active and to order the remaining as
backups. The Cisco Extended Functions application with the lowest IP address
becomes active. The application with the next lowest IP address becomes the
backup to the active application. Any remaining applications act as backups to
each other, beginning with the application with the next lowest IP address. If you
add any new applications to the cluster, Cisco Extended Functions restarts the
algorithm to determine which application will be active.

4-6

Note When a Cisco Extended Functions application gets started in a cluster, the Cisco

Extended Functions application with the lowest IP address becomes active. This
process may cause an interruption to Call Back for approximately 2 minutes.

To verify the directory status and Cisco Extended Functions application
registration status to the Cisco CTIManager, use the Real-Time Monitoring Tool
as described in the Cisco CallManager Serviceability Administration Guide.

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