User's Manual

2-5
Cisco Unified IP Phone Administration Guide for Cisco Unified Communications Manager 8.6 (SCCP and SIP)
OL-23091-01
Chapter 2 Preparing to Install the Cisco Unified IP Phones on Your Network
Understanding Phone Configuration Files
Obtaining Additional Information about Power
For related information about power, refer to the documents shown in Table 2-2. These documents
provide information about the following topics:
• Cisco switches that work with the Cisco Unified IP Phones
• The Cisco IOS releases that support bidirectional power negotiation
• Other requirements and restrictions regarding power
Understanding Phone Configuration Files
Phone configuration files are stored on the TFTP server and define parameters for connecting to Cisco
Unified
Communications Manager. 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’s 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. These load files are digitally signed to ensure the authenticity of the files’
source.
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. For SIP phones, a TLS connection requires that the transport protocol in the phone
configuration file be set to TLS, which corresponds to the transport type in the SIP Security Profile in
Cisco Unified Communications Manager Administration.
Note If the device security mode in the configuration file is set to Authenticated or Encrypted, but the phone
has not received a CTL or ITL file, the phone tries four times to obtain the file so it can register securely.
Note Cisco Extension Mobility Cross Cluster is an exception, in that the phone permits a TLS connection to
Cisco Unified Communications Manager for secure signaling even without the CTL file.
Ta b l e 2-2 Related Documentation for Power
Document Topics URL
Cisco Unified IP Phones 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/net
working_solutions_package.html
Cisco Catalyst Switches http://www.cisco.com/en/US/products/hw/switches/ps708/tsd_prod
ucts_support_series_home.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