Cisco CP-3911 - Unified SIP Phone 3911 VoIP Administration Manual page 21

Chapter 1 An Overview of the Cisco Unified IP Phone
Table 1-1 Supported Networking Protocols on the Cisco Unified IP Phone (continued)
Networking Protocol
Internet Protocol (IP)
Network Time Protocol
(NTP)
Real-Time Transport
(RTP)
Session Description
Protocol (SDP)
Cisco Unified SIP Phone 3911 Administration Guide for Cisco Unified Communications Manager
OL-14029-01
Purpose
IP is a messaging protocol that
addresses and sends packets across
the network.
NTP is a protocol that is used to
synchronize timekeeping among a set
of distributed time servers and
clients.
RTP is a standard protocol for
transporting real-time data, such as
interactive voice and video, over data
networks.
SDP is the portion of the SIP protocol
that determines which parameters are
available during a connection
between two endpoints. Conferences
are established using only the SDP
capabilities that are supported by all
endpoints in the conference.
What Networking Protocols Are Used?
Usage Notes
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 Unified IP Phone with
Dynamic Host Configuration
Protocol (DHCP). If you are not
using DHCP, you must manually
assign these properties to each phone
locally.
When you configure Network Time
Protocol (NTP) on Cisco Unified
Communications Manager
Administration, the Cisco Unified IP
phones will get the date and time
from an NTP server.
Cisco Unified IP Phones use the RTP
protocol to send and receive
real-time voice traffic from other
phones and gateways.
SDP capabilities, such as codec
types, DTMF detection, and comfort
noise are normally configured on a
global basis by the Cisco Unified
Communications Manager or the
Media Gateway in operation. Some
SIP endpoints may allow these
parameters to be configured on the
endpoint itself.
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