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Cisco Unified Communications Manager Architecture

  • Sample Chapter is provided courtesy of Cisco Press.
  • Date: Jun 9, 2008.

Chapter Description

This lesson introduces and describes the role, architecture, hardware and software requirements, and the licensing model of the CUCM.

CUCM Overview

Cisco Unified Communications (UC) is an IP-based communications system integrating voice, video, data, and mobility products and applications. It enables more effective, secure communications and can transform the way in which we communicate. UC represents a communications paradigm shift like that of the invention of the telegraph. UC removes the geographic barriers of effective communications through the use of voice, video, and data integration. Business can be conducted with a fluidity that progresses and evolves with you. Information has been at our fingertips for a long time, but UC enables the sharing of this information to create knowledge and value.

Cisco UC is part of an integrated solution that includes network infrastructure, security, mobility, network management products, lifecycle services, flexible deployment and outsourced management options, end-user and partner financing packages, and third-party communication applications.

Cisco UC can drastically change the bottom line of business by creating more effective communications without losing the personal nature of a face-to-face conversation. More effective communication leads to reduced time to market and nimble transformation of business processes through collaboration.

Cisco UC Solution Components

The Cisco UC strategy encompasses voice, video, and data traffic within a single network infrastructure. Cisco UC equipment is capable of managing all three traffic types and interfacing with all standards-based network protocols.

Cisco IP Communications represents a new way of delivering UC functionality to enterprise customers. Instead of delivering a collection of disjointed products with individual release dates, testing methodology, and documentation, Cisco UC is a coordinated release of an integrated set of products that are tested, documented, and supported as a system.

Figure 1-1 illustrates the four standard layers of the Cisco UC voice infrastructure model and the components that make up the layers.

Figure 1-1

Figure 1-1 Cisco Unified Communications Solution Components

The components of the standard layers are as follows:

  • Infrastructure layer: The infrastructure consists of routers, switches, and voice gateways. The infrastructure layer carries data, voice, and video between all network devices and applications. This layer also provides high availability, management, quality of service (QoS), and network security.
  • Call control layer: The call control layer provides for call processing, device control, and administration of the dial plan and features.

    Call control can be provided by a CUCM, CUCM Express, or CUCM Business Edition (CMBE). This book focuses on the CUCM product, which is almost identical to the Cisco Unified CMBE. Call processing is physically independent from the infrastructure layer. For example, a CUCM, Cisco Unified CMBE, or CUCM Express in San Jose can process call control for a device physically located in Chicago.

  • Applications layer: Applications are independent from call-control functions and the physical voice-processing infrastructure. Applications, including those listed here, are integrated through IP, which allows the applications to reside anywhere within the network:
    • Voice mail, integrated messaging, and unified messaging applications are provided through Cisco Unity, Cisco Unity Express, or Cisco Unity Connections products.
    • Contact centers of various sizes can be built with Cisco Unified Contact Center and Cisco Unified Contact Center Express.
    • Cisco Unified MeetingPlace and MeetingPlace Express are medium- to large-scale conferencing servers that support video integration. The MeetingPlace product integrates lecture-style conferences with scalable collaboration and control tools. Cisco Unified MeetingPlace Express is positioned to the small to medium-sized enterprises. MeetingPlace Express is the successor of the Cisco Conference Connection server.
    • Cisco Emergency Responder (ER) enhances the existing emergency functionality offered by CUCM. Cisco ER provides physical location updates for mobile devices to guarantee that emergency calls to the public safety answering point (PSAP) are properly routed to the PSAP in charge of emergency calls for that site. Cisco ER identifies the caller location and maps all calls from that physical location to an emergency line identification number (ELIN) through the use of standard automatic number identification (ANI)/caller identification (CLID). The ELIN is registered with the PSAP as an Emergency Response Location (ERL). Deploying this capability helps ensure more effective compliance with legal or regulatory obligations, thereby reducing the life and liability risks related to emergency calls.
    • The Cisco Unified Presence server collects information about the availability and communications capabilities of a user and provides this information to watchers of the user as a status indication. The status information includes the user's communications device availability. For example, the user might be available via phone, video, web collaboration, or videoconferencing.
    • Standard protocol interfaces, including Telephony Application Programming Interface (TAPI), Java Telephony Application Programming Interface (JTAPI), Simple Object Access Protocol (SOAP), Q.SIG, H.323, Media Gateway Control Protocol (MGCP), and Session Initiation Protocol (SIP) are available to support third-party applications.
  • Endpoints layer: The endpoints layer brings applications to the user, whether the end device is a Cisco IP Phone, a PC using a software-based phone, or a communications client or video terminal. Cisco UC provides multiprotocol support for Skinny Client Control Protocol (SCCP), H.323, MGCP, and SIP.

Cisco UC Network

The Cisco UC system delivers fully integrated communications, converging voice, video, and data over a single network infrastructure using standards-based protocols. The Cisco UC system delivers unparalleled performance and capabilities to address current and emerging communications needs in the enterprise environment, as illustrated by the network topology in Figure 1-2.

Figure 1-2

Figure 1-2 Cisco UC Network

The Cisco UC product suite is designed to optimize functionality, reduce configuration and maintenance requirements, and provide interoperability with a variety of other applications. It provides this capability while maintaining high availability, QoS, and security.

The Cisco UC system integrates the following major communications technologies:

  • IP telephony: IP telephony refers to technology that transmits voice communications over a network using IP standards. Cisco UC includes a wide array of hardware and software products such as call-processing agents, IP phones, voice-messaging systems, video devices, conferencing, and many other applications.
  • Customer contact center: Cisco Unified Contact Center products are a combination of strategy and architecture to revolutionize call center environments. Cisco Unified Contact Center promotes efficient and effective customer communications across large networks by enabling organizations to draw from a broader range of resources to service customers. These resources include access to a large pool of agents and multiple channels of communication and customer self-help tools.
  • Video telephony: The Cisco Unified Video Advantage products enable real-time video communications and collaboration using the same IP network and call-processing agent as Cisco UC. Cisco Unified Video Advantage does not require special end-user training. Video calling with Cisco Unified Video Advantage is as easy as dialing a phone number.
  • Rich-media conferencing: Cisco Unified MeetingPlace creates a virtual meeting environment with an integrated set of IP-based tools for voice, video, and web conferencing.
  • Third-party applications: Cisco works with leading-edge companies to provide the broadest selection of innovative third-party IP communications applications and products focused on critical business needs such as messaging, customer care, and workforce optimization.

CUCM Functions

CUCM extends enterprise telephony features and functions to packet telephony network devices. These packet telephony network devices include Cisco IP Phones, media-processing devices, VoIP gateways, and multimedia applications. Additional data, voice, and video services, such as converged messaging, multimedia conferencing, collaborative contact centers, and interactive multimedia response systems, interact with the IP telephony solution through the CUCM application programming interface (API).

CUCM provides these functions:

  • Call processing: Call processing refers to the complete process of originating, routing, and terminating calls, including any billing and statistical collection processes.
  • Signaling and device control: CUCM sets up all the signaling connections between call endpoints and directs devices such as phones, gateways, and conference bridges to establish and tear down streaming connections. Signaling is also referred to as call control and call setup/call teardown.
  • Dial plan administration: The dial plan is a set of configurable lists that CUCM uses to perform call routing. CUCM is responsible for digit analysis of all calls. CUCM enables users to create scalable dial plans.
  • Phone feature administration: CUCM extends services such as hold, transfer, forward, conference, speed dial, redial, call park, and many other features to IP phones and gateways.
  • Directory services: CUCM uses its own database to store user information. User authentication is performed locally or against an external directory. Directory synchronization allows for centralized user management. Directory synchronization allows CUCM to leverage users already configured in a corporate-wide directory. Microsoft Active Directory (2000 and 2003), Netscape 4.x, iPlanet 5.1, and Sun ONE 5.2 directory integrations are supported. The local CUCM database is a Lightweight Directory Access Protocol (LDAP)-compliant database (LDAPv3) component in the IBM Informix Database Server (IDS).
  • Programming interface to external applications: CUCM provides a programming interface to external applications such as Cisco IP SoftPhone, Cisco IP Communicator, Cisco Unified IP Interactive Voice Response (IP IVR), Cisco Personal Assistant, Cisco Unified Personal Communicator, and CUCM Attendant Console.
  • Backup and restore tools: CUCM provides a Disaster Recovery System (DRS) to back up and restore the CUCM configuration database. The DRS system also backs up call details records (CDR), call management records (CMR), and the CDR Analysis and Reporting (CAR) database.

Figure 1-3 shows IP phones that logically register with one of the CUCMs in the cluster. Multiple CUCM servers share one database, and the phone maintains an active connection to both the primary and backup CUCM server. The figure shows the phone's logical TCP/IP connections to the primary server.

Figure 1-3

Figure 1-3 CUCM Functions

CUCM Signaling and Media Paths

CUCM uses SIP or SCCP to communicate with Cisco IP Phones for call setup and teardown and for supplementary service tasks.

After a call has been set up, media exchange occurs directly between the Cisco IP Phones across the IP network, using the Real-Time Transport Protocol (RTP) to carry the audio. CUCM is not involved in a call after the call has been set up. If the CUCM server were unplugged during the duration of the call, users would not notice unless they attempted to use a feature on the phone. CUCM is involved only in call setup, teardown, and features. If the CUCM server that set up the call were down during a conversation, end users would see a message indicating "CM Down, Features Disabled" on the LCD screen of the IP phone.

Example: Basic IP Telephony Call

Figure 1-4 illustrates a user at phone A placing a call to phone B.

Figure 1-4

Figure 1-4 CUCM Signaling and Media Paths

At the beginning of a call, a user at IP phone A picks up the handset, and a message is sent to CUCM letting CUCM know that the device has gone off-hook. CUCM responds to this stimulus by replying with a message that tells the device to play the dial tone file that is stored in the flash memory of the phone. The user at phone A hears the dial tone and begins dialing the phone number of phone B. SCCP phones send their digits to CUCM as they are pressed (digit by digit), whereas SIP phones send their dialed digits in one message (enbloc signaling) by default. SIP phones have options that allow them to behave similarly to SCCP phones (Keypad Markup Language [KPML] and dial rules). CUCM performs digit analysis against the dialed digits. If a match is found, CUCM routes the call per its configuration. If CUCM does not find a match, a reorder tone is sent to the calling party.

CUCM signals the calling party to initiate ringback, so the user at phone A will hear the ringback tone. CUCM also signals the call to the destination phone, which plays the ringdown tone. Additional information is provided to the phones to indicate the calling and called party name and number. (Phone A will show the destination device name and number, and phone B will show the calling party name and number.)

When the user at phone B accepts the call, CUCM sends a message to the devices letting them know the IPv4 socket (IPv4 address and port number) information in which they should communicate for the duration of the call. The RTP media path opens directly between the two phones.

The Cisco IP Phones require no further communication with CUCM until either phone invokes a feature, such as call transfer, call conferencing, or call termination.

CUCM Hardware, Software, and Clustering

CUCM Release 6.0 is a complete hardware and software solution that works as a network appliance. A network appliance is a closed system that supports only Cisco-authorized applications and utilities. Goals of the appliance model are to simplify the installation and upgrade of the system and to hide the underlying operating system. An appliance-based model makes it possible for an administrator to install, implement, and manage a CUCM server without requiring knowledge of or having access to the underlying operating system.

The CUCM appliance has these features:

  • Complete hardware and software solution.

    CUCM servers are preinstalled with all software that is required to operate, maintain, secure, and manage a server or cluster of servers (including Cisco Security Agent).

    CUCM is also provided as a software-only product, which may be installed on supported Cisco Media Convergence Servers (MCS) or Cisco-approved third-party server platforms.

  • Appliance operating system provides ease of installation and upgrade, while also providing security and reliability.
  • You can upgrade CUCM servers while they continue to process calls.
  • System administration is performed via graphical user interface (GUI), command-line interface (CLI), and through documented APIs for third-party access.
  • Outputs a variety of management parameters via a published interface to provide information to approved management applications, such as NetIQ Vivinet Manager, HP OpenView, and Integrated Research PROGNOSIS.
  • Appliance operates with or without keyboard, mouse, and monitor (also known as headed or headless). Third-party access is allowed via documented APIs only.
  • CUCM supports clustering of servers for the purpose of redundancy and load sharing. Database redundancy is provided by sharing a common database across multiple servers. Call-processing redundancy is achieved through the Call Manager Group setting, in which multiple servers are assigned to a device for the purposes of providing fault tolerance.

A CUCM cluster can have up to 20 servers in it. Only one publisher server is allowed in the cluster. The publisher houses the read/write copy of the database. Up to eight subscriber servers can be in the cluster, with the restriction that only four of the subscriber servers can perform active call processing. If more than four subscriber servers are used in a cluster, the additional servers are dedicated standby servers in case the active subscriber server is not available. The other 11 servers in the cluster can be responsible for various services, including TFTP and media resources (conferencing, music on hold, transcoding).

CUCM Cluster

Clustering allows the network to scale to several thousands of endpoints, provides redundancy in case of network or server failure, and provides a central point of administration. Figure 1-5 displays a Publisher database synchronizing database components to all the other servers in the cluster. The servers running the CCM.exe process are performing call processing, and the other servers are taking on special roles described in later chapters of this book. CUCM clustering creates scalability by segregating processes to other machines, which increases performance.

Figure 1-5

Figure 1-5 CUCM Cluster

Device settings are stored in the IBM IDS database. The database is the repository for service parameters, features, device configurations, and dial plan configurations.

The database replicates nearly all configuration information in a hub-and-spoke topology (one publisher, many subscribers). CUCM nodes also use a second communication method to replicate runtime data using a mesh topology. (Every node updates every other node.) A mesh topology of information sharing provides dynamic registration and active call information that changes much more frequently than database changes. Real-time mesh replication is used to communicate newly registered phones, gateways, and digital signal processor (DSP) resources, guaranteeing optimum call routing.

Cisco 7800 Series Media Convergence Servers

Although it is possible for CUCM to run on most computers, Cisco supports CUCM running only on Cisco-approved hardware that they will support. The minimum hardware requirements for CUCM Release 6.0 are as follows:

  • 2-GHz processor
  • 2 GB RAM
  • 72-GB hard disk

Minimum requirements for CUCM 6 are the same as for Cisco Unified CallManager Version 5, but only specific MCS models are approved.

The 7800 series servers are available in the –H or –I variants. –H stands for Hewlett-Packard, and –I stands for IBM server platforms. The 7825 server is a 19-inch or 23-inch rack-mountable server that provides a single SATA hard drive and one power supply. The 7835 server improves reliability and performance by including hot-swappable SCSI hard drives, hardware RAID 1 disc duplexing, and redundant power supplies. The 7845 improves reliability and performance by providing a second CPU and a backup fan assembly.

You can find the most detailed, current Cisco hardware specifications at http://www.cisco.com/en/US/products/hw/voiceapp/ps378/prod_brochure0900aecd8062a4f9.html.

CUCM must be installed on a server that meets Cisco configuration standards. Cisco actively collaborates with two server hardware manufacturers to meet this requirement: Hewlett-Packard (HP) and IBM. You can find additional information at the following sites:

Cisco UC Operating System

The CUCM operating system is based on Red Hat Linux. Operating system and application updates are provided by Cisco through patches that are digitally signed by Cisco. Unsupported software and applications (not digitally signed by Cisco) cannot be uploaded or installed into the system.

Root access to the file system is not permitted. The operating system has been hardened by disabling all unnecessary accounts and services. There is also no access to native operating system debug interfaces. Traces, alarms, and performance counters can be enabled and monitored through the CUCM GUI. Some files and directories are accessible through the Cisco CLI and GUI for maintenance purposes.

Remote-access support allows Cisco Technical Assistance Center (TAC) engineers to remotely access the CUCM server for a restricted time interval. Remote-access support can be enabled in CUCM serviceability tools.

The IBM IDS is the database for the Cisco UC applications. The IDS database installation and configuration is scripted into the CUCM installation DVDs. No UNIX or IBM IDS database knowledge is required to configure and operate CUCM.

Cisco Secure Agent is included with the appliance to provide protection against known and unknown attacks. Cisco Secure Agent is a host-based intrusion prevention system (HIPS).

A DHCP server is integrated into CUCM to provide IP telephony devices with their IP addressing requirements.

The Cisco UC operating system is also used for these Cisco UC applications:

  • Cisco Emergency Responder 2.0
  • Unity Connection 2.0
  • Cisco Unified Presence 6.0

Cisco UC Database

The data in the CUCM database is divided into two types, as described in the sections that follow.

Static Configuration Data

Static configuration data is created as part of the configuration of the CUCM cluster. Read/write access to this data is provided for the publisher only. Subscribers provide only read-only access to this data. If the publisher becomes unavailable, the subscriber data can be used to process calls, but it cannot be modified. Database replication is unidirectional, from the publisher to the subscribers. Only CDRs and CMRs are replicated from the subscriber servers to the publisher. All other configuration information is downloaded from the publisher.

User-Facing Features

You have learned that the publisher is the only server with a read-write copy of the database, and all configuration changes should be made on the publisher. These changes are then replicated downstream to the subscribers. This model represents a single point of failure from the perspective of moves, adds, and changes (MAC). The problem is further exacerbated because the publisher was the only server in the cluster responsible for call-forwarding changes, extension mobility logins, and message-waiting indicators before CUCM 6.0.

CUCM 6.0 treats a portion of the database as dynamic configuration data. Read/write access to dynamic configuration data is provided on all servers, allowing certain information to be modified if the publisher server is unavailable. The dynamic information that can be changed during a publisher outage is known as user-facing features (UFF). UFF data is replicated from the subscriber servers where the change was initiated to all other subscriber servers in the CUCM cluster.

Examples of UFFs include the following:

  • Call Forward All (CFA)
  • Message Waiting Indication (MWI)
  • Privacy, Enable/Disable
  • Do Not Disturb, Enable/Disable (DND)
  • Extension Mobility Login (EM)
  • Hunt Group Login Status
  • Monitor (future use)
  • Device Mobility
  • CTI CAPF Status (Computer Telephony Integration, Certificate Authority Proxy Function)

The services listed in Table 1-1 rely on the availability of the publisher server regardless of the version of CUCM used.

Table 1-1. Publisher Server Required Services




Provisions everything


Provisions user settings


Provisions everything initiated by the Bulk Administration tool


Provisions everything initiated by the Tool for Auto-Registered Phone Support


Provisions everything initiated by the AVVID XML Layer service


Enables and disables services through SOAP


Inserts phones (auto-registration only)


Updates end-user information

License Audit

Updates license tables

Database Access Control

Database access is secured using the embedded Red Hat, iptables dynamic firewall and a database security password.

The procedure to allow new subscribers to access the database on the publisher is as follows:

  • Step 1 Add the subscriber to the publisher database using CUCM Administration.
  • Step 2 During installation of the subscriber, enter the same database security password that was entered during installation of the publisher.

After this configuration, the following process occurs to replicate the database from the publisher to the newly added subscriber:

  1. The subscriber attempts to establish a connection to the publisher database using the database management channel.
  2. The publisher verifies the subscriber's authenticity and adds the subscriber's IP address to its dynamic firewall (iptables).
  3. The subscriber is allowed to access the publisher database.
  4. The database content is replicated from the publisher to the subscriber.

Figure 1-6 illustrates the iptables firewall allowing subscriber access to the publisher database.

Figure 1-6

Figure 1-6 Database Access Control

You can find CUCM 6.0 TCP and UDP port usage information at http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/port/6_0/60plrev1.pdf.

CUCM Licensing

Licensing is implemented in CUCM beginning with Release 5.0. Administration of license management is done through CUCM GUI administration, allowing accurate tracking of active device registrations compared to the license units that have been purchased. License enforcement occurs at the time of phone provisioning and CUCM service activation.

The publisher is the only licensing server. The licensing server is the logical component that keeps track of the licenses purchased and the licenses used. If the publisher fails, no new phones can register, and no configuration changes will be allowed. Existing phones will continue to operate during a publisher outage.

CUCM tracks the license compliance for devices, applications, and software as follows:

  • Device units licenses: The maximum number of provisioned devices in the CUCM database will be tracked and enforced. Route points and CTI ports are not enforced.
  • Application licenses: Application licenses are required for every call-processing server running the CallManager service. Application licenses are tied to the MAC address of the network interface card (NIC) of the server.
  • Software licenses: Software licenses are tied to the major version of the software. Software licenses are required for upgrade to CUCM 6.

Licenses are created and distributed in accordance with the Cisco FlexLM process. Cisco product license registration is performed at http://www.cisco.com/go/license.

These two types of product IDs are available:

  • Cisco device license units: Cisco device license units (DLU) are for Cisco devices only.
  • Third-party device license units: Third-party DLUs can be converted to Cisco units, but not vice versa.

CUCM tracks the number of units required by each device, as shown in Figure 1-7. Each device type corresponds to a fixed number of units.

Figure 1-7

Figure 1-7 Device License Units

The number of DLUs consumed per device depends on the device type and capabilities of the phone.

The number of units required per device can be viewed from CUCM Administration. DLUs are perpetual and device independent. Figure 1-7 displays the number of DLUs consumed in CUCM 6.0 by some popular phones.

The main components of the license file are as follows:

  • MAC address of the license server (publisher)
  • Version (major release) of the CUCM software
  • Number of node licenses (number of CUCM servers in cluster)
  • Number of DLUs

License files are additive. (Multiple license files can be loaded.) The Cisco FlexLM process is used to obtain licenses, and integrity of license files is assured by a digital signature.

When upgrading from Cisco Unified CallManager 4.x, the number of DLUs required is calculated during the CUCM migration process, and an intermediate XML file containing these license counts is generated. The number of devices and servers that are in the database at the time of migration is the basis for the number of DLUs and node licenses in the interim license file. No additional phones may be added until the interim license file has been replaced by a real license file.

After upgrading to CUCM 6.0(1), use the View File option in the License File Upload window to view the intermediate XML file. Copy and paste the intermediate license file into the CUCM License Upgrade window on Cisco.com to obtain the actual license file. Upload the actual license file to the publisher (license server).

Existing device and node licenses from CUCM 5.x can be used in CUCM 6.x.

Example 1-1 shows an example license file.

Example 1-1. Example License File

INCREMENT PHONE_UNIT cisco 6.0 permanent uncounted VENDOR_STRING=<Count>1000</Count><OrigMacId>000BCD4EE59D</OrigMacId>
  <LicFileVersion>1.0</L icFileVersion> HOSTID=000bcd4ee59d NOTICE="<LicFileID>20050826140539162</LicFileID><LicLineID>2
  </LicLineID> <PAK></PAK>" SIGN="112D 17E4 A755 5EDC F616 0F2B B820 AA9C 0313 A36F B317 F359 1E08 5E15 E524 1915 66EA BC9F A82B CBC8 4CAF 2930 017F D594 3E44 EBA3 04CD 01BF 38BA BF1B"

Significant fields are highlighted and described as follows:

  • INCREMENT PHONE_UNIT Cisco 6.0 indicates a phone unit license file for Cisco Unified CM 6.0. There is no expiration date for this license, as indicated by the keyword permanent.
  • This license file includes 1000 license units.
  • The MAC address of the license server is 000BCD4EE59D.

License File Request Process

Figure 1-8 displays the license file request process, which includes these steps:

  1. The customer places an order for CUCM.
  2. The manufacturing database scans the Product Authorization Key (PAK) and records it against the sales order.
  3. The product (CD or paper claim certificate) is physically delivered to the customer.
  4. The customer registers the product at http://www.cisco.com/go/license or a public web page and provides the MAC address of the publisher device that will become the license server.
  5. The license fulfillment infrastructure validates the PAK, and the license key generator creates a license file.
  6. The license file is delivered via e-mail to the customer. The e-mail also contains instructions on how to install the license file.
  7. The customer installs the license file on the license server (publisher).
Figure 1-8

Figure 1-8 License File Request Process

Obtaining Additional Licenses

The process of obtaining additional DLUs and node licenses is as follows:

  1. The customer places an order for the additional licenses for a license server (publisher MAC address has to be specified).
  2. When the order is received, Cisco.com generates a license file with the additional count and sends it to the customer.
  3. The new license file has to be uploaded to the license server and will be cumulative.

Consider this example. A CUCM server has an existing license file that contains 100 DLUs. Another 100 DLUs are purchased. The second license file that is generated will contain only 100 DLUs. When the new license file with 100 DLUs is uploaded to CUCM, the 100 DLUs from the first license file are added to the devices of the second license file, resulting in a total of 200 DLUs.

Licensing Components

The key licensing components of CUCM licensing are the license server and the license manager.

License Server

The license server service runs on the publisher in the CUCM cluster and is responsible for keeping track of the licenses purchased and consumed. The MAC address of the publisher is required to generate a license file.

License Manager

The license manager acts as a broker between CUCM applications that use licensing information and the license server. The license manager receives requests from the CUCM applications and forwards the requests to the license server. The license manager then responds back to the application after the request has been processed by the license server. The license manager acts a licensing proxy server.

An administration subsystem and alarm subsystem complete the functional diagram. Details of these two subsystems are as follows:

  • The administration subsystem provides the following capabilities:
    • Keeps information about the license units required for each phone type. The customer can view this information using a GUI.
    • Supports a GUI tool that calculates the required number of phone unit licenses. The customer inputs phone types and the number of phones of each type that the customer wants to purchase. The output is the total number of licenses that the customer needs for the given configuration.
    • Supports a GUI tool that displays the total license capacity and the number of licenses in use and license file details. The tool can also report the number of available licenses.
  • The alarm subsystem generates alarms that are routed to event logs or sent to a management station as Simple Network Management Protocol (SNMP) traps to notify the administrator of the following conditions:
    • —Overdraft: Occurs when an overdraft condition exists. An overdraft condition occurs when more licenses are used than available but the amount of exceeding licenses is in an acceptable range. (5 percent overdraft is permitted.)
    • —License server down: Occurs when the License Manager cannot reach the license server.
    • —Insufficient licenses: Occurs when the license server detects the fact that there are not sufficient licenses to fulfill the request and raises an alarm to notify the administrator.

Issues with the license file occur when there is a version mismatch between the license file and the CUCM (license file version mismatch alarm), or when the number of licenses in the license file is less than the number of phones provisioned (license file insufficient licenses alarm). Another cause of this condition is an invalid MAC address (for instance, after a NIC change).

Figure 1-9 is a functional diagram stepping through the process of a license request, as described in the list that follows:

  1. A request for a certain number of DLUs is made by the admin subsystem because of an event (for example, phone registration).
  2. The License Manager service on a CUCM subscriber forwards the request to the publisher server running the License Server service.
  3. The License Server service receives the license request event and allocates the required number of DLUs required based on the type of device. If not enough license units are available to accommodate the request, a deny message is sent back to the license manager on the subscriber server. If resources are available, the license server grants the request and sends a grant message to the license manager on the subscriber server.
  4. The License Manager service on the subscriber server receives the license grant or deny message and allows the phone to register.
  5. If the license request was denied, the subscriber server generates an alarm in the alarm subsystem. The deny message will be available in the CUCM syslog server by default.
Figure 1-9

Figure 1-9 Licensing Functional Diagram

Calculating License Units

To calculate the number of phone licenses required, follow these steps:

  • Step 1 Choose System > License > License Unit Calculator. The License Unit Calculator window displays. The number of license units consumed per device and the current number of devices display as shown in Figure 1-10.
    Figure 1-10

    Figure 1-10 License Unit Calculator

  • Step 2 In the Number of Devices column, enter the desired number of devices, corresponding to each node or phone.
  • Step 3 Click Calculate. The total number of CUCM node license units and DLUs required for specified configuration will display.

License Unit Reporting

License unit reports can be run to verify the number of licenses consumed and available for future expansion. Use the following procedure to generate a license unit report:

  • Step 1 Choose System > License > License Unit Report.
  • Step 2 The License Unit Report window displays as shown in Figure 1-11. This window displays the number of phone licenses and number of node licenses, in these categories:
    • Units Authorized
    • Units Used
    • Units Remaining
Figure 1-11

Figure 1-11 License Unit Report

License files (CCMxxxxx.lic) are uploaded to the publisher (license server). To upload a license file to the publisher server, follow these steps:

  • Step 1 Ensure that the license file is downloaded to a local PC.
  • Step 2 From the PC and using a supported browser, log in to CUCM Administration.
  • Step 3 Choose System > License > License File Upload, as shown in Figure 1-12. The License File Upload window displays.
    Figure 1-12

    Figure 1-12 License File Upload Procedure

  • Step 4 In the window shown in Figure 1-13, click Upload License File.
    Figure 1-13

    Figure 1-13 License File Upload Procedure

  • Step 5 Click Browse to choose the license file from the local directory.
  • Step 6 Click Upload.
  • Step 7 After the upload process has completed, click the Continue prompt when it appears. The content of the newly uploaded license file will display.
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Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@ciscopress.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by Cisco Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.ciscopress.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020