Cisco 7821 Administration Manual page 26

VLAN Interaction
Network protocol
Transmission Control
Protocol (TCP)
Transport Layer Security
(TLS)
Trivial File Transfer
Protocol (TFTP)
User Datagram Protocol
(UDP)
Related Topics
Verify Network Setup, on page 33
Verify Phone Startup, on page 43
VLAN Interaction
The Cisco IP Phone contains an internal Ethernet switch, enabling forwarding of packets to the phone, and
to the computer (access) port and the network port on the back of the phone.
If a computer is connected to the computer (access) port, the computer and the phone share the same physical
link to the switch and share the same port on the switch. This shared physical link has the following implications
for the VLAN configuration on the network:
• The current VLANs might be configured on an IP subnet basis. However, additional IP addresses might
Cisco IP Phone 7821, 7841, and 7861 Administration Guide for Cisco Unified Communications Manager 10.0
(SIP)
12
Purpose
TCP is a connection-oriented transport
protocol.
TLS is a standard protocol for securing
and authenticating communications.
TFTP allows you to transfer files over the
network.
On the Cisco IP Phone, TFTP enables
you to obtain a configuration file specific
to the phone type.
UDP is a connectionless messaging
protocol for delivery of data packets.
not be available to assign the phone to the same subnet as other devices that connect to the same port.
Usage notes
Cisco IP Phones use TCP to connect
to Cisco Unified Communications
Manager and to access XML
services.
When security is implemented, Cisco
IP Phones use the TLS protocol when
securely registering with Cisco
Unified Communications Manager.
For more information, see
Cisco Unified Communications
Manager Security Guide.
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 the IP address of the
TFTP server by using the Network
Setup menu on the phone.
For more information, see
"Cisco TFTP" chapter in the Cisco
Unified Communications Manager
System Guide.
Cisco IP Phones transmit and receive
RTP streams, which utilize UDP.