Chapter 1 An Overview of the Cisco IP Phone
What Networking Protocols are Used?
1-6
Cisco IP Phone Administration Guide for Cisco CallManager, Cisco IP Phone 7961G/7961G-GE and 7941G/7941G-GE
OL-6966-01
Cisco Discovery
Protocol (CDP)
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.
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.
Dynamic Host
Configuration Protocol
(DHCP)
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
you needing to manually assign an IP
address or to configure additional
network parameters.
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 DCHP
configurations, refer to the
Cisco CallManager System Guide.
Internet Protocol (IP) IP is a messaging protocol that
addresses and sends packets across
the network.
To communicate using IP, network
devices must have an assigned IP
address, subnet, and gateway.
IP addresses, subnets, and gateways
identifications are automatically
assigned if you are using the
Cisco IP Phone with Dynamic Host
Configuration Protocol (DHCP). If
you are not using DHCP, you must
manually assign these properties to
each phone locally.
Real-Time Transport
Protocol (RTP)
RTP is a standard protocol for
transporting real-time data, such as
interactive voice and video, over data
networks.
Cisco IP Phones use the RTP
protocol to send and receive
real-time voice traffic from other
phones and gateways.
Table 1-1 Supported Networking Protocols on the Cisco IP Phone (continued)
Networking Protocol Purpose Usage Notes