SECTION 5
GLOSSARY
5-10 SECTION
5,
GLOSSARY
T
TCP
Transmission Control Protocol on OSI Transport Layer 4 provides
reliable transport over the network for data transmitted using IP
(network layer three). It is an end-to-end protocol defining rules
and procedures for data exchange between hosts on top of
connectionless IP. TCP uses a timer to track outstanding packets,
checks error in incoming packets, and retransmits packets if
requested.
TCP/IP
The Transmission Control Protocol/Internet Protocol suite
provides standards and rules for data communication between
networks on the Internet. It is the worldwide Internetworking
standard and the basic communications protocol of the Internet.
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
