Cisco 7821 Administration Manual page 23

Network protocol
Cisco Discovery Protocol
(CDP)
Dynamic Host
Configuration Protocol
(DHCP)
Hypertext Transfer
Protocol (HTTP)
Hypertext Transfer
Protocol Secure (HTTPS)
Cisco IP Phone 7821, 7841, and 7861 Administration Guide for Cisco Unified Communications Manager 10.0 (SIP)
Purpose
CDP is a device-discovery protocol that
runs on all Cisco-manufactured
equipment.
Using CDP, a device can advertise its
existence to other devices and receive
information about other devices in the
network.
DHCP dynamically allocates and assigns
an IP address to network devices.
DHCP enables you to connect an IP
phone into the network and have the
phone become operational without your
needing to manually assign an IP address
or to configure additional network
parameters.
HTTP is the standard way of transferring
information and moving documents
across the Internet and the web.
Hypertext Transfer Protocol Secure
(HTTPS) is a combination of the
Hypertext Transfer Protocol with the
SSL/TLS protocol to provide encryption
and secure identification of servers.
IP phones can be HTTPS clients;
Note
they cannot be HTTPS servers.
Supported Network Protocols
Usage notes
The Cisco IP Phone uses CDP to
communicate information such as
auxiliary VLAN ID, per port power
management details, and Quality of
Service (QoS) configuration
information with the Cisco Catalyst
switch.
DHCP is enabled by default. If
disabled, you must manually
configure the IP address, subnet
mask, gateway, and a TFTP server
on each phone locally.
Cisco recommends that you use
DHCP custom option 150. With this
method, you configure the TFTP
server IP address as the option value.
For additional supported DHCP
configurations, go to the "Dynamic
Host Configuration Protocol" chapter
and the "Cisco TFTP" chapter in the
Cisco Unified Communications
Manager System Guide.
If you cannot use option
Note
150, you may try using
DHCP option 66.
Cisco IP Phones use HTTP for the
XML services and for
troubleshooting purposes.
Web applications with both HTTP
and HTTPS support have two URLs
configured. Cisco IP Phones that
support HTTPS choose the HTTPS
URL.
A lock icon is displayed to the user
if the connection to the service is via
HTTPS.
9