Glossary
Section 5
WE800G
5-11
Tunnel
To place packets inside other packets to send over a network.
The protocol of the enclosing packet is understood by each
endpoint, or tunnel interface, where the packet enters and exits
the network. VPNs rely on tunneling to create a secure network.
Tunneling requires the following protocol types:
!
A carrier protocol, such as TCP, used by the network that the
data travels over
!
An encapsulating protocol, such as IPSec, L2F, L2TP, or
PPTP, that is wrapped around the original data
!
A passenger protocol, such as IP, for the original data
U
UDP
User Datagram Protocol. A method used along with the IP to
send data in the form of message units (datagram) between
network devices over a LAN or WAN.
Unicast
A point-to-point data transmission sent from one sender to one
receiver. This the normal way you access websites. See also
multicast
.
UPnP
Universal Plug and Play
USB
Universal Serial Bus is a computer interface for add-on devices
such as printers, scanners, mice, modems, or keyboards. USB
supports data transfer rates of 12 Mbps and plug-and-play
installation. You can connect up to 127 devices to a single USB
port.
V
VoIP
Voice over Internet Protocol is a method to exchange voice, fax,
and other information over the Internet. Voice and fax have
traditionally been carried over traditional telephone lines of the
PSTN (Public Switched Telephone Network) using a dedicated
circuit for each line. VoIP enables calls to travel as discrete data
packets on shared lines. VoIP is an important part of the
convergence of computers, telephones, and television into a
single integrated information network.
