OL-1742-01
C H A P T E R 8
Cisco TFTP
The Cisco TFTP service builds and serves files consistent with the trivial file
transfer protocol, which is a simplified version of the File Transfer
Protocol (FTP). Cisco TFTP builds configuration files and serves embedded
component executables, ringer files, and device configuration files.
A configuration file contains a prioritized list of Cisco CallManagers for a device
(telephones and gateways), the TCP port on which the device connects to those
Cisco CallManagers, and an executable load identifier. Configuration files for
Cisco IP Phone 7960 and 7940 models also contain URLs for the phone buttons:
messages, directories, services, and information. Configuration files for gateways
contain all their configuration information.
Configuration files may be in a .cnf format or a .cnf.xml format, depending on the
device type and your TFTP service parameter settings. When you set the
BuildCNFFlag service parameter to True, the TFTP server builds both .cnf.xml
and .cnf format configuration files for devices. When you set the parameter to
False, the TFTP server builds only .cnf.xml files for devices.
This section describes the relationship among Cisco CallManager, TFTP, and
Dynamic Configuration Protocol (DHCP) as well as the relationship between
devices and the TFTP server. This section contains the following topics:
• TFTP Process Overview, page 8-2
• Understanding How Devices Use DHCP and Cisco TFTP, page 8-3
• Understanding How Devices Access the TFTP Server, page 8-5
• Understanding How Devices Identify the TFTP Server, page 8-6
• Alternate TFTP Paths, page 8-7
8-1
Cisco CallManager System Guide
Chapter 8 Cisco TFTP
TFTP Process Overview
• TFTP Configuration Checklist, page 8-7
• Where to Find More Information, page 8-8
TFTP Process Overview
The TFTP server can handle simultaneous requests for configuration files. This
section describes the request process.
When a device boots, it queries a DHCP server for its network configuration
information. The