2-7
Cisco Unified IP Phone 6921, 6941, 6945, and 6961 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)
OL-23769-01
Chapter
Understanding the Phone Startup Process
Understanding the Phone Startup Process
When connecting to the VoIP network, the Cisco Unified IP Phone 6921, 6941, and 6961 go through a
standard startup process that is described in Table 2-3. Depending on your specific network setup, not
all of these steps may occur on your Cisco Unified IP Phone.
Table 2-3 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
attached to the phone.
• Adding Phones to the Cisco Unified CM Database,
page 2-8.
• Resolving Startup Problems, page 9-1.
2. Loading the Stored Phone 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.
Resolving Startup Problems, page 9-1.
3. Configuring VLAN
If the Cisco Unified IP Phone is connected to a
Cisco Catalyst switch, the switch next informs the
phone of the voice VLAN defined on the switch. The
phone needs to know its VLAN membership before it
can proceed with the Dynamic Host Configuration
Protocol (DHCP) request for an IP address.
• Network Setup Menu, page 4-4.
• 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.
• Network Setup Menu, page 4-4.
• 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.
• Network Setup Menu, page 4-4.
• Resolving Startup Problems, page 9-1.
6. Requesting the CTL file
The TFTP server stores the certificate trust list (CTL)
file. The CTL file contains the certificates necessary
for establishing a secure connection between the
phone and Cisco Unified CM.
Refer to the Cisco Unified Communications Manager
Security Guide, “Configuring the Cisco CTL Client”
chapter.