DHCP Service Setup Cont Phone Bootup

The IP phone powers on

The phone performs a Power on Self Test (POST)

The phone boots up

Through CDP the IP phone learns what the auxiliary VLAN is

On the Cisco CME router a DHCP Scope can be configured. The scope should define the following:

• Range of available IP addresses

• A default gateway

• The address of the TFTP server

The phone initializes the IP stack

Continued next slide...

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When an IP phone first receives power, the following steps happen:

■ Receives power - The IP phone receives power

■ POST - The phone will perform some basic tests called a Power On Self Test (POST).

■ Boot - The IP phone will then bootstrap

■ Discover the Voice VLAN - Learn which VLAN is the voice VLAN through the layer 2 Cisco Discovery Protocol (CDP).

■ Initialize the IP stack - The IP phone will then initialize a basic IP stack.

P I elephony

IP phone send DHCP Discover broadcast requesting an IP address

IP phone send DHCP Discover broadcast requesting an IP address

DHCP server selects a free IP address from the pool and sends along with the other scope parameters as a DHCP Offer

The IP phone initializes applies the IP configuration to the IP stack

The IP phone requests it configuration file from the TFTP server

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The process of a phone booting up continues with the following:

■ Send DHCP Discover - By default, the IP phone (DHCP client) will then send a DHCP request to the broadcast address

■ DHCP server assigns an IP address - If this broadcast is heard by a local DHCP server, the server will assign a free IP address, the subnet mask for the scope, the default gateway for the scope, the DNS server (optional) for the scope, and a TFTP server (option 150) for the scope

■ DHCP Offer -The Scope setting will be sent to the DHCP client (the IP phone) using the broadcast address of

■ IP phone initialized DHCP settings - The IP phone will take the values received from the DHCP response and apply them to the IP stack of the IP phone

■ Request configuration from TFTP server - The IP phone will use the value received in option 150 to attempt to get a configuration file from the TFTP server (Cisco CME router is always the TFTP server in Cisco CME)

P T elephony

These commands are not needed for the IP phones if the automated setup is used because the setup will prompt for these setting and configure a DHCP scope automatically. However, if it is not configured or the administrator wishes to manually configure or change the settings the following commands will need to be used.

The command ip dhcp exclude-address start-IP end-IP allows the administrator to exclude static addresses within the scope range that might be statically assigned to a server or router interface. For Cisco CME the exclusions should include the IP address of the routers interface that may be local to the IP phones.

The command ip dhcp pool pool-name defines and creates a DHCP pool. After this command has been executed, the router will be in a DHCP sub mode. The automated setup mode will create a DHCP pool named ITS (the old name of the Cisco CME product).

Note The pool name is case-sensitive.

Within the DHCP sub mode under a pool, enter the network subnet subnet-mask command to assign a range of IP addresses to be available for DHCP clients to be assigned. This will not include any exclusion previously defined. The lowest available IP address will be used first when the addresses are assigned. In Cisco CME, this will be the subnet on which the IP phones are.

The command default-router IP-address will set option 003 on the DHCP scope that is being defined. This option will send the IP address of the default gateway to the DHCP client. The default gateway for Cisco CME will be the router interface that is on the same subnet as the IP phones.

The optional command dns-server primary-IP secondary-IP allows the DNS server to be sent in option 006 to the DHCP clients. For Cisco CME, this setting becomes important if names will be used for any of the URL values that can be assigned. Lack of a DNS server has the effect of requiring use of IP addresses only.

Finally, a critical command that must be configured correctly is the custom option for the TFTP server. This is configured using the command option 150 ip CallManagerExpress-IP. This IP address must be the IP address on the Cisco CME router with which the IP phones register.

DHCP Service Setup (Cont.)

Configuring DHCP on an IOS router

CMERouter(config)#ip dhcp exluded-address CMERouter(config)#ip dhcp pool mypool

CMERouter(dhcp-config)#network CMERouter(dhcp-config)#option 150 ip CMERouter(dhcp-config)#default-router CMERouter(dhcp-config)#dns-server CMERouter(dhcp-config)#exit

• Option 150 sets the TFTP server on the IP phone

• The TFTP server contains the configuration files and firmware for the IP phone

This is a sample configuration in which the DHCP server is the Cisco CME router. This shows the command option 150 ip, where is the IP address of a local interface on the Cisco CME router.

IP Phone Registration


This topic describes IP phone firmware files and XML configuration files.

This topic describes IP phone firmware files and XML configuration files.

There are some files that are necessary for the proper operation of the IP phone or analog device so that it may register successfully with the Cisco CME router. The files that will be needed include:

■ Firmware - The firmware is loaded into memory on the IP phone and will survive a reboot

■ XMLDefault.cnf.xml - An XML configuration file that will specify the proper firmware, address, and port needed for the new phone to register

■ SEPAAAABBBBCCCC. cnf.xml - An XML configuration file that is specific for one device based on the MAC address

■ SCCP-dictionary.xml - An XML file that contains the device labels for the locale selected

■ Phonemodel-dictionary.xml - An XML file that contains possible messages and dialogs that can appear on the screen of the IP phone for the selected locale

■ Phonemodel-tones.xml - An XML file that contains the cadence and rings for the specified locale

All of the necessary firmware files for IP phones are stored internally on the Cisco CME router flash, so an external database or file server is not required. IP Phones will download firmware files from the router flash using Trivial File Transfer Protocol (TFTP) during registration. All

Cisco CME configuration and language files are located in the Dynamic RAM (DRAM) of the router under system:/its/.

Firmware is installed in flash RAM with the Cisco CME software or individually as needed

Served up by the TFTP server on the Cisco CME router

The command tftp-server flash:firmware-file-name

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The firmware of the supported devices within Cisco CME is stored in the flash memory of the Cisco CME router. These firmware files are installed in flash memory when the Cisco CME software is extracted and installed. The firmware required will vary with the devices, and needs to be available when a new phone or a phone with a different version of firmware comes online. The firmware files need to be made available through a TFTP server. This is done with the command tftp-server flashfirmware-file-name.

This command as well as other related commands will be covered in more detail in the next lesson.

The firmware names with .sbin are signed phone loads. Once a signed phone load is installed on a phone, that phone cannot go back to an unsigned phone load. The phone will always have to use a signed phone load even if used by CallManager.


These files are specific to Cisco CME 3.1 and will vary with the version of Cisco CME.

Model Firmware file

ATA-186 ata18x-v2-16-ms-030327b.zup

ATA-188 ata18x-v2-16-ms-030327b.zup

7902 CP7902010200SCCP031023A.sbin























Free Xml For Cisco Phone

The XML file SEPAAAABBBBCCCC.cnf.xml (where AAAABBBBCCCC is the MAC address of the IP phone) contains the IP address, port, firmware, locale, directory URL and many others, some of which cannot be currently used in Cisco CME. This file is generated by the system during the initialization of the Cisco CME software when the command create-cnf-files is found in the startup-config. This command and other related commands will be covered in more detail in the next lesson.

In the graphic, the configuration file contains the IP address and port representing the interface and port to which the phone will attempt to register on the Cisco CME router. Within the configuration file there is also a language defined that will be applied to the IP phone in question.

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