Cisco Unified IP Phone and Telephony Networks

Phone and Telephony Networks Overview

Cisco Unified IP Phones enable you to communicate by using voice over a data network. To provide this capability, the IP Phones depend upon and interact with several other important Cisco Unified IP Telephony components, including Cisco Unified Communications Manager.

This chapter focuses on the interactions between the Cisco Unified IP Phone 6901 and 6911, Cisco Unified Communications Manager, DNS and DHCP servers, TFTP servers, and switches. It also describes options for powering phones.

For related information about voice and IP communications, go to this URL:

http://www.cisco.com/c/en/us/products/unified-communications/index.html

Cisco Unified IP Communications Product Interactions

To function in the IP telephony network, the Cisco Unified IP Phone must be connected to a networking device, such as a Cisco Catalyst switch. You must also register the Cisco Unified IP Phone with a Cisco Unified Communications Manager system before sending and receiving calls.

Cisco Unified IP Phone and Cisco Unified Communications Manager Interactions

Cisco Unified Communications Manager is an open and industry-standard call processing system. Cisco Unified Communications Manager software sets up and tears down calls between phones, integrating traditional PBX functionality with the corporate IP network. Cisco Unified Communications Manager manages the components of the IP telephony system: the phones, the access gateways, and the resources necessary for features such as call conferencing and route planning. Cisco Unified Communications Manager also provides:

  • Firmware for phones

  • Configuration file using the TFTP service

  • Phone registration

  • Call preservation, so that a media session continues if signaling is lost between the primary Communications Manager and a phone

For information about configuring Cisco Unified Communications Manager to work with the IP phones described in this chapter, see the "Cisco Unified IP Phone Configuration" chapter in the Cisco Communications Manager Administration Guide.


Note

If the Cisco Unified IP Phone model that you want to configure does not appear in the Phone Type drop-down list in Cisco Unified Communications Manager, go to the following URL and install the latest support patch for your version of Cisco Unified Communications Manager:

http://tools.cisco.com/support/downloads/go/Redirect.x?mdfid=278875240

For more information, see the "Software Upgrades" chapter in the Cisco Unified Communications Operating System Administration Guide.

Cisco Unified IP Phone 6911 and VLAN Interaction

The Cisco Unified IP Phone 6911 has an internal Ethernet switch, enabling forwarding of packets to the phone, and to the access port and the network port on the back of the phone.


Note

The Cisco Unified IP Phone 6901 does not have a PC port.

If a computer is connected to the access port, the computer and the phone share the same physical link to the switch and share the same port on the switch. This shared physical link has the following implications for the VLAN configuration on the network:

  • The current VLANs might be configured on an IP subnet basis. However, additional IP addresses might not be available to assign the phone to the same subnet as other devices connected to the same port.

  • Data traffic present on the VLAN supporting phones might reduce the quality of VoIP traffic.

  • Network security may require isolation of the VLAN voice traffic from the VLAN data traffic.

You can resolve these issues by isolating the voice traffic onto a separate VLAN. The switch port that the phone connects to would be configured to have separate VLANs for carrying:

  • Voice traffic to and from the IP Phone (auxiliary VLAN on the Cisco Catalyst 6000 series, for example)

  • Data traffic to and from the PC connected to the switch through the access port of the IP Phone (native VLAN)

Isolating the phones on a separate, auxiliary VLAN increases the quality of the voice traffic and allows a large number of phones to be added to an existing network when there are not enough IP addresses for each phone.

For more information, refer to the documentation included with a Cisco switch. You can also access switch information at this URL:

http://cisco.com/en/US/products/hw/switches/index.html

Cisco Unified IP Phone and Cisco Unified Communications Manager Express Interaction

When the Cisco Unified IP Phone works with the Cisco Unified Communications Manager Express (Unified CME), the phones must go into CME mode.

When a user invokes the conference feature, the tag allows the phone to use either a local or network hardware conference bridge.

The Cisco Unified IP Phones do not support the following actions:

Transfer

Only supported in the connected call transfer scenario.

Conference

Only supported in the connected call transfer scenario.

Join

Supported using the Conference button or Hookflash access.

Hold

Supported using the Hold button.

Barge

Not supported.

Direct Transfer

Not supported.

Select

Not supported.

The users cannot create conference and transfer calls across different lines.

Cisco Unified IP Phone Power

The Cisco Unified IP Phone 6901 and 6911 can be powered with external power or with Power over Ethernet (PoE). A separate power supply provides external power. A switch provides PoE through the Ethernet cable attached to a phone.


Caution

When you install an externally powered phone, connect the power supply to the phone and to a power outlet before you connect the Ethernet cable to the phone. When you remove an externally powered phone, disconnect the Ethernet cable from the phone before you disconnect the power supply.

Power Guidelines

The following table provides guidelines for powering the Cisco Unified IP Phone 6901 and 6911.

Table 1. Guidelines for Powering the Cisco Unified IP Phone 6901 and 6911

Type

Guidelines

External power, provided through the CP-PWR-CUBE-3 external power supply.

The Cisco Unified IP Phone 6901 and 6911 use the CP-PWR-CUBE-3 power supply.

External power, provided through the Cisco Unified IP Phone Power Injector.

The Cisco Unified IP Phone Power Injector may be used with any Cisco Unified IP Phone. Functioning as a midspan device, the injector delivers inline power to the attached phone. The Cisco Unified IP Phone Power Injector connects between a switch port and the IP Phone, and supports a maximum cable length of 100 meter (m) between the unpowered switch and the IP Phone.

PoE power, provided by a switch through the Ethernet cable attached to the phone.

The Cisco Unified IP Phone 6901 and 6911 support Cisco inline PoE.

The Cisco Unified IP Phone 6901 and 6911 support IEEE 802.3af Class 1 power on signal pairs and spare pairs.

To ensure uninterruptible operation of the phone, make sure that the switch has a backup power supply.

Make sure that the CatOS or IOS version running on your switch supports your intended phone deployment. Refer to the documentation for your switch for operating system version information.

External power, provided through inline power patch panel WS-PWR-PANEL

The inline power patch panel WS-PWR-PANEL is compatible with the Cisco Unified IP Phone 6901 and 6911.

Power Outage

Your access to emergency service through the phone requires the phone to receive power. If an interruption in the power supply occurs, Service and Emergency Calling Service dialing do not function until power is restored. In the case of a power failure or disruption, you may need to reset or reconfigure equipment before you can use the Service or Emergency Calling Service dialing.

Additional Information About Power

The documents in the following table provide more information on the following topics:

  • Cisco switches that work with Cisco Unified IP Phones

  • Cisco IOS releases that support bidirectional power negotiation

  • Other requirements and restrictions about power

Document topics

URL

Cisco Unified IP Phone Power Injector

http://www.cisco.com/en/US/products/ps6951/index.html

PoE Solutions

http://www.cisco.com/en/US/netsol/ns340/ns394/ns147/ns412/index.html

Cisco Catalyst Switches

http://www.cisco.com/en/US/products/hw/switches/index.html

Integrated Service Routers

http://www.cisco.com/en/US/products/hw/routers/index.html

Cisco IOS Software

http://www.cisco.com/en/US/products/sw/iosswrel/products_ios_cisco_ios_software_category_home.html

Phone Configuration Files

The TFTP server stores the phone configuration files that define Cisco Unified Communications Manager connection parameters. In general, any time you make a change in Cisco Unified Communications Manager that requires the phone to be reset, a change is automatically made to the phone configuration file.

Configuration files also contain information about which image load the phone should be running. If this image load differs from the one currently loaded on a phone, the phone contacts the TFTP server to request the required load files.

In addition, if the device security mode in the configuration file is set to Authenticated and the CTL file on the phone has a valid certificate for Cisco Unified Communications Manager, the phone establishes a TLS connection to Cisco Unified Communications Manager. Otherwise, the phone establishes a TCP connection.


Note

If the device security mode in the configuration file is set to Authenticated or Encrypted, but the phone has not received a CTL file, the phone tries four times to obtain a CTL file so it can register securely.

If you configure security-related settings in Cisco Unified Communications Manager, the phone configuration file contains sensitive information. To ensure the privacy of a configuration file, you must configure it for encryption. For detailed information, see the " Configuring Encrypted Phone Configuration Files" chapter in Cisco Unified Communications Manager Security Guide. A phone requests a configuration file whenever it resets and registers with Cisco Unified Communications Manager.

A phone accesses a default configuration file named XmlDefault.cnf.xml from the TFTP server when the following conditions exist:

  • You have enabled autoregistration in Cisco Unified Communications Manager

  • The phone has not been added to the Cisco Unified Communications Manager database

  • The phone is registering for the first time

If autoregistration is not enabled and the phone is not added to the Cisco Unified Communications Manager database, the system rejects the phone registration request.

If the phone registers and works in encrypted mode, the phone accesses the configuration file named SEPmac_address.cnf.xml.enc.sgn. If the SEPmac_address.cnf.xml.enc.sgn does not exist on the TFTP server, the phone requests the file SEPmac_address.cnf.xml.sgn. That is, if the phone works in encrypted mode with TFTP Encrypted Config selected, the phone accesses the configuration file named SEPMac_addr.cnf.xml.enc.sgn. If the phone works in encrypted mode with TFTP Encrypted Config not selected, the phone accesses the file SEPMac_addr.cnf.xml.sgn. To enable TFTP Encrypted Configuration, select the TFTP Encrypted Config check box in the Phone Security Profile Configuration page. You can access this page from the Cisco Unified Communications Manager by selecting System > Security > Phone Security Profile and clicking Add New.

For SIP phones, the TFTP server generates these SIP configuration files:

  • SIP IP Phone:

    • For unsigned and unencrypted files - SEP<mac>.cnf.xml

    • For signed files - SEP<mac>.cnf.xml.sgn

    • For signed and encrypted files - SEP<mac>.cnf.xml.enc.sgn

  • Dial Plan - <dialplan>.xml

The filenames derive from the MAC address and description fields in the Phone Configuration window of Cisco Unified Communications Manager. The MAC address uniquely identifies the phone.

For more information on phone configuration settings, see the "Cisco Unified IP Phone Configuration" chapter in the Cisco Communications Manager Administration Guide.

Phone Startup Process

When connecting to the VoIP network, the Cisco Unified IP Phone 6901 and 6911 go through a standard startup process that is described in the following list. Depending on your specific network configuration, not all these steps may occur on your Cisco Unified IP Phone.

  1. Obtain power from the switch. If a phone does not use external power, the switch provides in-line power through the Ethernet cable attached to the phone. For more information, see Cisco Unified Communications Manager Phone Addition Methods and Startup Problems.

  2. Configure VLAN. If the Cisco Unified IP Phone connects to a Cisco Catalyst switch, the switch informs the phone of the voice VLAN defined on the switch. The phone needs to know the VLAN membership before proceeding with the Dynamic Host Configuration Protocol (DHCP) request for an IP address.

    For more information, see Cisco Unified IP Phone Network Settings Setup and Startup Problems.

  3. Obtain an IP address. If the Cisco Unified IP Phone uses DHCP to obtain an IP address, the phone queries the DHCP server to obtainthe address. If you are not using DHCP in your network, you must assign static IP addresses to each phone locally.

    For more information, see Cisco Unified IP Phone Network Settings Setup and Startup Problems.

  4. Access a TFTP server. In addition to assigning an IP address, the DHCP server directs the Cisco Unified IP Phone to a TFTP Server. If the phone has a statically defined IP address, you must configure the TFTP server locally on the phone; the phone then contacts the TFTP server directly.


    Note

    You can also assign an alternative TFTP server to use instead of the one assigned by DHCP.

    For more information, see Cisco Unified IP Phone Network Settings Setup and Startup Problems.

  5. Request the configuration file. The TFTP server stores configuration files that define parameters for connecting to Cisco Unified Communications Manager and other information for the phone.

    For more information, see Cisco Unified Communications Manager Phone Addition Methods and Startup Problems.

  6. Load the stored phone image. The Cisco Unified IP Phone has nonvolatile flash memory to store firmware images and user-defined preferences. At startup, the phone runs a bootstrap loader that loads a phone image stored in flash memory. Using this image, the phone initializes the software and hardware.

    For more information, see Startup Problems.

  7. Contact Cisco Unified Communications Manager. The configuration file defines how the Cisco Unified IP Phone communicates with Cisco Unified Communications Manager and provides a phone with the load ID. After obtaining the file from the TFTP server, the phone attempts to make a connection to the highest priority Cisco Unified Communications Manager on the list.

    If the phone was manually added to the database, Cisco Unified Communications Manager identifies the phone. If the phone was not manually added to the database and autoregistration is enabled in Cisco Unified Communications Manager, the phone attempts to autoregister in the Cisco Unified Communications Manager database.

    For more information, see Startup Problems

Cisco Unified Communications Manager Phone Addition Methods

Before installing the Cisco Unified IP Phone, you must choose a method for adding phones to the Cisco Unified Communications Manager database. Each phone type requires a fixed number of device license units and the available number of unit licenses on the server may impact phone registration. For more information on licensing, see the "Licenses for Phones" section in the Cisco Unified Communications Manager System Guide.

The following table provides an overview of the Cisco Unified Communications Manager phone addition methods.

Table 2. Methods for Adding Phones to the Cisco Unified Communications Manager Database

Method

Requires MAC address?

Notes

Autoregistration

No

Results in automatic assignment of directory numbers.

Not available when security or encryption is enabled.

Autoregistration with TAPS

No

Requires autoregistration and the Bulk Administration Tool (BAT); updates information in the Cisco Unified IP Phone and in Cisco Unified Communications Manager Administration

Using the Cisco Unified Communications Manager Administration

Yes

Requires phones to be added individually

Using BAT

Yes

Allows for simultaneous registration of multiple phones

Autoregistration Phone Addition

By enabling autoregistration before you begin installing phones, you can:

  • Add phones without first gathering MAC addresses from the phones.

  • Automatically add a Cisco Unified IP Phone to the Cisco Unified Communications Manager database when you physically connect the phone to your IP telephony network. During autoregistration, Cisco Unified Communications Manager assigns the next available sequential directory number to the phone.

  • Quickly enter phones into the Cisco Unified Communications Manager database and modify any settings, such as the directory numbers, from Cisco Unified Communications Manager.

  • Move autoregistered phones to new locations and assign them to different device pools without affecting their directory numbers.


Note

Cisco recommends you use autoregistration to add less than 100 phones to your network. To add more than 100 phones to your network, use the Bulk Administration Tool (BAT). See Add Phones Using BAT Phone Template.

The system disables autoregistration by default. In some cases, you might not want to use autoregistration; for example, if you want to assign a specific directory number to the phone. For information about enabling autoregistration, see the "Enabling Autoregistration" section in the Cisco Unified Communications Manager Administration Guide.


Note

When you configure the cluster for mixed mode through the Cisco CTL client, autoregistration automatically disables. When you configure the cluster for nonsecure mode through the Cisco CTL client, autoregistration automatically enables.

Autoregistration and TAPS Phone Addition

You can add phones with autoregistration the Tool for Auto-Registered Phones Support (TAPS), without first gathering MAC addresses from phones.

TAPS works with the Bulk Administration Tool (BAT) to update a batch of phones that were already added to the Cisco Unified Communications Manager database with dummy MAC addresses. Use TAPS to update MAC addresses and download predefined phone configuration files.


Note

Cisco recommends you use autoregistration and TAPS to add less than 100 phones to your network. To add more than 100 phones to your network, use the Bulk Administration Tool (BAT). See Add Phones Using BAT Phone Template.

To implement TAPS, you or the end user dial a TAPS directory number and follow the voice prompts. When the process completes, the phone has downloaded the directory number and other settings, and the Cisco Unified Communications Manager database contains the correct MAC address for the phone.

Autoregistration must be enabled in Cisco Unified Communications Manager (System > Cisco Unified CM) for TAPS to function.


Note

When you configure the cluster for mixed mode through the Cisco CTL client, autoregistration is automatically disabled. When you configure the cluster for nonsecure mode through the Cisco CTL client, autoregistration is automatically enabled.

For more information, see the "Bulk Administration" chapter in Cisco Unified Communications Manager Administration Guide.

Cisco Unified Communications Manager Phone Addition

You can add phones individually to the Cisco Unified Communications Manager database using Cisco Unified Communications Manager administration. To do so, you first obtain the MAC address for each phone.

For information about determining a MAC address, see Cisco Unified IP Phone MAC Address Determination.

After you have collected MAC addresses, in Cisco Unified Communications Manager Administration, choose Device > Phone and click Add New to begin.

For complete instructions and conceptual information about Cisco Unified Communications Manager, see the "Cisco Unified Communications Manager Overview" chapter in the Cisco Unified Communications Manager System Guide.

Add Phones Using BAT Phone Template

The Cisco Unified Communications Manager Bulk Administration Tool (BAT) enables you to perform batch operations, including registration, on multiple phones. To access BAT, choose Bulk Administration in Cisco Unified Communications Manager Administration,

To add phones by using BAT only (not in conjunction with TAPS), you must obtain the appropriate MAC address for each phone.

For information about determining a MAC address, see Cisco Unified IP Phone MAC Address Determination.

For detailed instructions about adding phones using the Bulk Administration menu, see the Cisco Unified Communications Manager Bulk Administration Guide, chapter "Inserting Phones".

To add a phone to the Cisco Unified Communications Manager using the BAT phone template, perform these steps:

Procedure

Step 1

From Cisco Unified Communications Manager, choose Bulk Administration > Phones > Phone Template.

Step 2

Click Add New.

Step 3

Choose a Phone Type and click Next.

Step 4

Enter the details of phone specific parameters, including Device Pool, Phone Button Template, and Device Security Profile.

Step 5

Click Save.

Step 6

From Cisco Unified Communications Manager, choose Device > Phone > Add New to add a phone using an existing BAT phone template.

Cisco Unified IP Phones and Different Protocols

The Cisco Unified IP Phone can operate with SCCP (Skinny Client Control Protocol) or SIP (Session Initiation Protocol). You can convert a phone that is using one protocol to use the other protocol.

Convert New Phone from SCCP to SIP

A new, unused phone uses SCCP. To convert this phone to SIP, perform these steps:

Procedure

Step 1

Take one of these actions:

  • To autoregister the phone, set the Auto Registration Phone Protocol parameter in Cisco Unified Communications Manager to SIP.

  • To provision the phone using the Bulk Administration Tool (BAT), choose the appropriate phone model and choose SIP from the BAT.

    For more information, see Cisco Unified Communications Manager Bulk Administration Guide.

  • To provision the phone manually, make the appropriate changes for SIP on the Phone configuration window in Cisco Unified Communications Manager.

    For more information, see Cisco Unified Commiunications Manager Administration Guide.

Step 2

If you are not using DHCP in your network, configure the network parameters for the phone. See Network Settings.

Step 3

To save the configuration updates,

  1. Click Apply Config.

  2. When the Apply Configuration Information window displays, click OK.

  3. Tell the user to power cycle the phone.

In-Use Phone Protocol to Protocol Conversion

Phones using SCCP can be upgraded to use SIP. To change from SCCP to SIP, the phone firmware must be updated to the recommended SIP version before the phones can register. New Cisco Unified IP Phones ship from the factory with SCCP phone firmware. These new phones must be upgraded to the recommended SIP version before they can complete registration.

For information about how to convert an in-use phone from one protocol to the other, see the Cisco Unified Communications Manager Administration Guide, chapter "Cisco Unified IP Phone Configuration", section "Migration Existing Phone Configuration to a Different Phone".

Deploy Phone in SCCP and SIP Environment

To deploy Cisco Unified IP Phones in an environment that includes SCCP and SIP and in which the Cisco Unified Communications Manager autoregistration parameter specifies SCCP, perform these general steps:

Procedure

Step 1

Set the Cisco Unified Communications Manager auto_registration_protocol parameter to SCCP.

Step 2

From Cisco Unified Communications Manager, choose System > Enterprise Parameters.

Step 3

Install the phones.

Step 4

Change the Auto Registration Protocol enterprise parameter to SIP.

Step 5

Autoregister the SIP phones.

Cisco Unified IP Phone MAC Address Determination

Several procedures described in this manual require you to determine the MAC address of a Cisco Unified IP Phone. You can determine the MAC address of a phone in these ways:

  • Look at the MAC label on the back of the phone.

  • Display the web page for the phone and click the Device Information hyperlink.