TCP/IP (Transmission Control Protocol/
Internet Protocol)
The basic communication language or protocol of
the Internet. It can also be used as a communica-
tions protocol in a private network (either an intranet
or an extranet). When you are set up with direct
access to the Internet, your computer is provided
with a copy of the TCP/IP program just as every
other computer that you may send messages to or
get information from also has a copy of TCP/IP.
Telnet (“Terminal Emulation”)
Protocol that enables you to log in to other computer
systems on the Internet.
Terminal
Computer terminal; a device that is able to communi-
cate (usually asynchronously) with a host computer.
Time to Live (TTL)
A value in an Internet Protocol (IP) packet that tells a
network router whether or not the packet has been in
the network too long and should be discarded.
Transport Stream
A multiplex of several program streams that are
carried in packets. Demultiplexing is achieved by
different packet IDs (PIDs).
See PSI, PAT, PMT, and PCR.
UDP (User Datagram Protocol)
A connectionless transport layer protocol in the
TCP/IP protocol stack (RFC 768).
UDP is a simple protocol that exchanges datagrams
without acknowledgments or guaranteed delivery,
requiring that error processing and retransmission
be handled by other protocols.
Unicast
Communication between a single sender and a
single receiver on a network. Streaming content can
be sent unicast from one server to one user.
Compare with Multicast.
VBR (Variable Bit Rate)
A term that describes how video or audio is
encoded. Variable bit rate provides a specifi ed
throughput capacity but data is not sent evenly.
Videoconferencing
Communication across long distances with video
and audio contact that may also include graphics
and data exchange. Digital video transmission
systems typically consist of camera, codec (Encod-
er-Decoder), network access equipment, network,
and audio system, e.g. EASI™ BLUEbox devices.
VLAN (Virtual LAN)
Network confi guration, emulating a broadcast
domain, where stations communicate using LAN
protocols as if they were on the same LAN, but
where they are actually on multiple segments
connected through layers 1, 2, and/or 3.
Wide Area Network (WAN)
A geographically dispersed telecommunications
network. The term distinguishes a broader telecom-
munication structure from a local area network (LAN).
A wide area network connects local area networks to
one another, generally using public infrastructure or
services. The connections are made using the
shared public infrastructure, public infrastructure
leased for private use, and sometimes, private
infrastructure (e.g., fi ber) with public services.
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Glossary