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Glossary
109
December, 2005 Vodavi Telenium IP Product Guide
mobility ▪ presence ▪ collaboration ▪ convergence
Encryption The translation of data into a secret code. Encryption is the most effective way to achieve data
security. To read an encrypted file, you must have access to a secret key or password that
enables you to decrypt it. Unencrypted data is called plain text ; encrypted data is referred to as
cipher text.
Enterprise A business organization or agency that generally relies on computers and networks.
Ethernet A 10 Mbps-network which can run over coaxial, twisted-pair, or fiber connections. Ethernet
specifies standards at the Physical and Data Link layers (Layers 1 and 2).
Extranet An extranet is a private network that uses the Internet to share part of a business's information
with trusted outside parties. An extranet can be viewed as part of a company's intranet that is
extended to users outside the company.
Failover When one device or system stops working and another device automatically takes its place, or
when a failure to connect via one path results in an attempt to connect via another path. For
example, a VOIP call that cannot be completed may be automatically failed over to a PRI line.
Fast Ethernet Ethernet boosted to the speed of 100 Mbps using Category 5 UTP, fiber-optic cable, or Category 3
UTP with special wiring considerations.
Fault
Tolerance A means of reducing or eliminating the possibility for system failure. For example, a server may
have two power supplies installed in it. If the main power supply fails, the second power supply
automatically assumes the main power supply role without the server losing power.
Fixed Wireless Wireless devices or systems in fixed locations such as homes and offices. Although mobile and
portable systems can be used in fixed locations, efficiency and bandwidth are compromised
compared with fixed wireless systems.
Flow Control The management of data flow between nodes in a network so that the data does not arrive too
quickly to be processed by the receiving node.
Frame Relay Frame relay is an access standard defined by the ITU-T that uses a form of packet switching
similar to X.25 networks. The packets are in the form of frames. A frame relay network can
accommodate data packets of various sizes associated with virtually any native data protocol. It
does not provide any method to correct errors but relies on the sender and destination to deal
with errors in packets.
Frame
Tagging
See DiffServ
FTP File Transfer Protocol. An Internet standard for leaving or retrieving files on a server using
TCP/IP.
Full Duplex Full-duplex data transmission means that data can be transmitted in both directions on a signal
carrier at the same time. For example, on a local area network with a technology that has full-
duplex transmission, one workstation can be sending data on the line while another workstation is
receiving data. Full-duplex transmission necessarily implies a bidirectional line (one that can move
data in both directions).
G.711 An algorithm designed to transmit and receive A-law and U-law PCM voice at digital bit rates of
48, 56, and 64 Kbps. It is used for digital telephone sets on digital PBX and ISDN channels.
(ITU-T Recommendation)
G.723.1 This algorithm is for compressed digital audio over POTS lines (Plain Old Telephone Lines). It runs
at 6.3 or 5.4 Kbps and uses linear predictive coding. (ITU-T Recommendation)
G.729 This ITU-T standard voice algorithm is a CS-ACELP (Conjugate Structure Algebraic Code Excited
Linear Predictive) voice algorithm for the coding of encoding/decoding of speech at 8 Kbps using
conjugate-structure, algebraic-code excited linear predictive methods.
Gatekeeper When using the H.323 voice over IP protocols, the gatekeeper is the device providing call control
to the endpoints.
Gbps Gigabits per second. A gigabit is one billion bits of data.