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Cisco Unified IP Phone Administration Guide for Cisco Unified Communications Manager 8.5
OL-23092-01
Chapter 2 Preparing to Install the Cisco Unified IP Phone on Your Network
Understanding the Phone Startup Process
Understanding the Phone Startup Process
When connecting to the VoIP network, the Cisco Unified IP Phone goes through a standard startup
process, as described in Table 2-4. Depending on your specific network configuration, not all of these
process steps may occur on your Cisco Unified IP Phone.
Table 2-4 Cisco Unified IP Phone Startup Process
Task Purpose Related Topics
1. Obtaining Power from the Switch.
If a phone is not using external power, the switch provides
in-line power through the Ethernet cable that is attached to
the phone.
See Providing Power to the Phone, page 2-4.
See Resolving Startup Problems, page 9-1.
2. Loading the StoredPhone Image.
The Cisco Unified IP Phone has non-volatile flash memory
in which it stores 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 its software and hardware.
See Resolving Startup Problems, page 9-1.
3. Configuring VLAN.
If the Cisco Unified IP Phone is connected to a Cisco
switch, the switch next informs the phone of the voice
VLAN defined on the switch port. The phone needs to
know its VLAN membership before it can proceed with the
Dynamic Host Configuration Protocol (DHCP) request for
an IP address.
See Network Configuration Menu, page 4-5.
See Resolving Startup Problems, page 9-1.
4. Obtaining an IP Address.
If the Cisco Unified IP Phone is using DHCP to obtain an
IP address, the phone queries the DHCP server to obtain
one. If you are not using DHCP in your network, you must
assign static IP addresses to each phone locally.
See Network Configuration Menu, page 4-5.
See Resolving Startup Problems, page 9-1.
5. Accessing 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.
See Network Configuration Menu, page 4-5.
See Resolving Startup Problems, page 9-1.
6. Requesting the CTL file.
The TFTP server stores the CTL file. This file contains the
certificates necessary for establishing a secure connection
between the phone and Cisco Unified Communications
Manager.
Refer to Cisco Unified Communications Manager
Security Guide, Configuring the Cisco CTL
Client.