Avaya C460 - Manual (Page 263)

Glossary
Avaya C460 Reference Guide 251
Protocol
A set of rules and conventions that governs how devices exchange data, especially
across a network. Low level protocols define the electrical and physical standards to
be observed, bit- and byte-ordering, the transmission, error detection, and
correction of the bit stream. High level protocols deal with data formatting,
including message syntax, terminal to computer dialogue, character sets, message
sequencing, etc.
Protocol Stack
A layered set of protocols which work together to provide a set of network
functions. Each intermediate layer uses the layer below it to provide a service to the
layer above.
PSTN
Public Switched Telephone Network. The collection of interconnected systems
operated by the various telephone companies and administrations around the
world.
PVC
Permanent Virtual Circuit. A permanent, virtual connection established by the
network management between an origin and a destination.
QoS
Quality of Service. A measure of performance for a transmission system that reflects
the system’s transmission quality and service availability.
Query
The process of extracting information from a database and presenting it for use.
RADIUS
Remote Authentication Dial-In User Service (RFC 2138). A protocol for carrying
authentication, authorization, and configuration information between a Network
Access Server and a shared Authentication Server.
Redundancy
A duplication of devices, services, or connections so that in the event of a failure, the
redundant device, service, or connection can take over for the one that failed.
Repeater
A device that automatically amplifies, restores, or reshapes signals distorted by
transmission loss.