Cisco 8821

The phone displays the date and time from Cisco Unified Communications Manager. If the user turns off
Automatic date and time in the Settings application, the time may become out of sync with the server
time.
Note
Network Protocols
The Cisco Wireless IP Phone 8821 and 8821-EX supports several industry-standard and Cisco network
protocols required for voice communication. The following table provides an overview of the network protocols
that the phones support.
Table 2: Supported Network Protocols
Usage notesPurposeNetwork protocol
The phones support Bluetooth 4.0.Bluetooth is a wireless personal area network
(WPAN) protocol that specifies how devices
communicate over short distances.
Bluetooth
—
BootP enables a network device, such as the Cisco
IP Phone, to discover certain startup information,
such as the IP address.
Bootstrap Protocol
(BootP)
The phones use CAST as an interface between
CUVA and Cisco Unified Communications Manager
using the Cisco IP Phone as a SIP proxy.
The CAST protocol allows Cisco IP Phones and
associated applications to discover and communicate
with the remote IP Phones without requiring changes
to the traditional signaling components, such as
Cisco Unified Communications Manager (CM) and
gateways.
Cisco Audio Session
Tunnel (CAST)
CPPDP is used by the Peer Firmware Sharing
feature.
CPPDP is a Cisco proprietary protocol used to form
a peer-to-peer hierarchy of devices. This hierarchy
is used to distribute firmware files from peer devices
to their neighboring devices.
Cisco Peer-to-Peer
Distribution Protocol
(CPPDP)
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.
We recommend that you use DHCP custom option
150. With this method, you configure the TFTP
server IP address as the option value. For more
information, see the documentation for your
particular Cisco Unified Communications Manager
release.
If you cannot use option 150, you may try
using DHCP option 66.
Note
DHCP dynamically allocates and assigns an IP
address to network devices.
DHCP enables you to connect an IP phone into the
network and the phone to become operational
without the need to manually assign an IP address
or to configure additional network parameters.
Dynamic Host
Configuration Protocol
(DHCP)
Cisco Wireless IP Phone 8821 and 8821-EX Administration Guide for Cisco Unified Communications Manager
16
VoIP Networks
Network Protocols