Chapter1 An Overview of the Cisco Unified IP Phone
Understanding the SIP Protocol
1-8
Cisco Unified IP Phone Administration Guide for Cisco Unified CallManager 5.1 (SIP), Cisco Unified IP Phones
OL-11524-01
Related Topics
•Understanding the SIP Protocol, page1-8
•Understanding Interactions with Other Cisco UnifiedIP Communications
Products, page 2-2
•Understanding the Phone Startup Process, page2-9
•Network Configuration Menu, page 4-7
Understanding the SIP Protocol
Session Initiation Protocol (SIP) is the Internet Engineering Task Force (IETF)
standard for multimedia conferencing over IP. SIP is an ASCII-based,
application-layer control protocol (defined in RFC3261) that can be used to
establish, maintain, and terminate calls between two or more endpoints.
Like other VoIP protocols, SIP is designed to address the functions of signaling
and session management within a packet telephony network. Signaling allows call
information to be carried across network boundaries. Session management
provides the ability to control the attributes of an end-to-end call.
Trivial File Transfer
Protocol (TFTP)
TFTP allows you to transfer files
over the network.
On the Cisco UnifiedIP Phone,
TFTP enables you to obtain a
configuration file specific to the
phone type.
TFTP requires a TFTP server in your
network, which can be automatically
identified from the DHCP server. If
you want a phone to use a TFTP
server other than the one specified by
the DHCP server, you must manually
assign TFTP server from the
Network Configuration menu on the
phone.
User Datagram Protocol
(UDP)
UDP is a connectionless messaging
protocol for delivery of data packets.
Cisco Unified IP Phones transmit and
receive RTP streams, which utilize
UDP.
Table1-1 Supported Networking Protocols on the Cisco UnifiedIP Phone (continued)
Networking Protocol Purpose Usage Notes