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Cisco Unified Communications System Fundamentals

  • Sample Chapter is provided courtesy of Cisco Press.
  • Date: Sep 10, 2004.

Chapter Description

This chapter will help you get started in administrating Cisco's Unified Communications System, with an understanding of how the system routes calls and information, as well as an understanding of the utilities available to administrators.

From the Book

Cisco Unity Fundamentals

Cisco Unity Fundamentals


Upon completing this chapter, you will be able to perform the following tasks:

  • Describe how calls are routed between Cisco servers and telephone switching equipment

  • Describe the flow of information between Cisco Unity servers and telephone switching equipment

  • Describe the features available in Cisco Unity 4.0

  • Describe the features available in Cisco Personal Assistant (PA) 1.4

This chapter introduces the Cisco unified communications system. To administer Cisco Unity and Cisco PA efficiently and effectively, it is important to have an understanding of the environment they inhabit and operate within. Understanding how calls route through the systems and what you can do with them as they travel is crucial to your ability to administer a Cisco unified communications system.

Understanding Cisco Unity's Call Flow Essentials

Understanding how calls flow through the unified communications systems is very important for system administrators of PA and the voice-messaging system Cisco Unity. As you become more familiar with how calls flow through the system, you will be able to change the flow as needed and troubleshoot problems more efficiently.

Outside Caller Call Flow

In Cisco Unity, an outside caller is someone who Cisco Unity cannot identify as a Cisco Unity subscriber. Generally, this is a person who is calling in from the outside who wants to reach an individual at a place of business. When a subscriber is busy or away from their phone, Cisco Unity can answer the call and take a message for them. The subscriber can later hear their message either over the phone or by using IBM Lotus Notes, Microsoft Outlook, or Cisco Unity Inbox (depending on the configuration setup of the Cisco Unity system). In addition, if Cisco Unity subscribers call in from a phone other than their defined office extension, Cisco Unity treats those calls as outside callers until they sign in and identify themselves.

Figure 1-1 illustrates how a call from an outside caller might flow through the system, the corresponding steps of which are described next:

Figure 1Figure 1-1 Cisco Unity Outside Caller Call Flow


Step 1

The outside caller dials a phone number from his mobile phone. The phone number dialed is a Direct Inward Dialing (DID) number that belongs to a Cisco Unity subscriber.

Step 2

The Public System Telephone Network (PSTN) routes the caller to the office communications equipment.

Step 3

The DID number is programmed to ring a phone extension. Based on DID information provided by the PSTN, the business telephone system sends the incoming call to the telephone that it is programmed to connect to that DID number.

Step 4

The telephone rings four times, but the subscriber does not answer the phone because he is busy working on a presentation. The telephone system has been programmed to forward any unanswered calls to voice mail after four rings. The telephone system forwards the outside caller to the voice-mail system.

Step 5

Cisco Unity receives the call and the extension of the subscriber to take a message for. Cisco Unity has a list of subscriber extensions and the e-mail aliases to send messages to. Cisco Unity records a message from the caller, addresses it to the subscriber's alias, and then sends it to the message store server.

Step 6

The message store server receives the message and stores the message for the subscriber.

Step 7

While Cisco Unity is monitoring events in the message store, it notices a new voice-mail message for the subscriber and sends the message waiting indicator (MWI) ON code to the telephone system for the subscriber's extension.

Step 8

The telephone system lights the lamp at the subscriber's telephone set. The telephone now displays an MWI to alert the subscriber of a new message.


If a previous message had been sent to this subscriber, the MWI would have been activated at that time. Therefore, the lamp or indicator remains activated.

Subscriber Call Flow

A Cisco Unity subscriber is a person who has a user account on the Cisco Unity system. Each subscriber account has a Profile page that stores specific information about that subscriber, such as the extension, security code, recorded name, and the e-mail alias to send messages to.

Figure 1-2 illustrates the call flow of a subscriber who is retrieving a message from Cisco Unity, the corresponding steps of which are described next:

Figure 2Figure 1-2 Cisco Unity Subscriber Call Flow


Step 1

The subscriber notices the MWI on her telephone and calls the voice-mail system to retrieve messages.

Step 2

The telephone system directs the call and the caller information (the telephone extension) to the Cisco Unity system.

Step 3

Cisco Unity receives the call and the extension of the telephone from the telephone system. Cisco Unity recognizes the extension from its list of subscribers, and accesses the subscriber's e-mail message store to retrieve the voice message. Cisco Unity asks the subscriber to enter her password. After entering the password, Cisco Unity offers to play the message for the subscriber.

Step 4

The subscriber chooses to listen to the message. Cisco Unity plays it and then offers a menu of actions to take with the message, such as save as new, delete, or forward. The subscriber presses the digit 3 to delete the message. While the subscriber is listening to the message, Cisco Unity sends an MWI OFF code. If the subscriber hangs up while the message is being played or does not press 3, then the MWI turns back on.

Step 5

Cisco Unity verbally confirms to the subscriber that the message is deleted and sends the subscriber's delete message command to the message store server.

Step 6

The message store deletes the message. (The message is either deleted or moved to the deleted items folder, depending on the settings in the subscriber's account.)

Step 7

Cisco Unity sends the MWI OFF code to the telephone system.

Step 8

The telephone system receives the MWI OFF code and turns off the MWI on the phone.

Step 9

The MWI of the telephone is off.

Cisco PA Outside Caller Call Flow

Cisco PA is a system that provides a way to connect calls to the particular telephone number at which you can be reached at a given time. When callers try to contact you through Cisco PA, you can set it up with different instructions on where you would like to be reached depending on the calling number and time.

Figure 1-3 illustrates how a call from an outside caller might flow through a system that is using Cisco PA, the corresponding steps of which are described next:

Figure 3Figure 1-3 Cisco PA Outside Caller Call Flow


Step 1

The outside caller dials a phone number from his cell phone. The phone number dialed is a DID number that belongs to a Cisco PA subscriber.

Step 2

The PSTN routes the caller to the office communications equipment. (Cisco PA integrates only with Cisco CallManager.)

Step 3

Cisco CallManager has been set up to route the DID call to Cisco PA's media ports.

Step 4

Cisco PA receives the call and the DID information.

Step 5

Cisco PA checks the subscriber's transfer rules and the current date and time so it can correctly process the call based on previous instructions the subscriber has given Cisco PA. At that time, the rules indicate the subscriber wants all calls sent to the desk phone.

Step 6

Cisco PA sends an initiate-transfer sequence to Cisco CallManager, along with the extension to which the call should be transferred.

Step 7

The subscriber receives the call at his desk.

Cisco PA Subscriber Call Flow

As a subscriber to Cisco PA, you can set up specific rules to manage when and where the calls you receive go. You can also use speech recognition with a corporate directory (or personal address book) to have PA dial a telephone number by saying the name of the user.

Figure 1-4 illustrates a call flow of a subscriber interacting with PA, the corresponding steps of which are described next:

Figure 4Figure 1-4 Cisco PA Subscriber Call Flow


Step 1

The subscriber wants to call Pat Carpenter on Pat's mobile number. The subscriber picks up the handset and dials the extension of Cisco PA.

Step 2

Cisco CallManager makes the connection between the subscriber's phone and an available media port (called a computer telephony integration [CTI] route point in Cisco CallManager) on Cisco PA.

Step 3

PA requires the subscriber to log on. After the subscriber is logged on, Cisco PA asks the subscriber what to do. In response to this question, the subscriber says "Call Pat Carpenter's mobile phone."

Step 4

Cisco PA performs the speech recognition and looks for a match in the corporate directory, where it finds an entry for Pat's mobile phone. Cisco PA then sends the transfer-initiate sequence to Cisco CallManager and the telephone number to connect the call.

Step 5

Cisco CallManager receives the request and the phone number. It makes a connection to the appropriate office communications equipment and sends Pat's mobile number to the PSTN.

Step 6

Pat's mobile phone rings, and Pat answers the phone.

2. Understanding Unified Communications Integrations | Next Section

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