Nortel BayStack 820, Installation And Reference Manual

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206901-A
Glossary-5
packet A group of bits, including data and control signals, arranged in a specific
format and transmitted as a whole. The structure of a packet depends on the
protocol. In general, a packet includes three principal elements: control
information (such as destination, origin, length of packet), data to be
transmitted, and error detection and correction bits.
PAP
Password Authentication Protocol. A method of establishing security on PPP
links where the caller must provide a password in order to establish the link.
PBX
Private Branch Exchange. A private telephone exchange, such as a company
switchboard, typically used and operated by a business, that provides internal
communication and access to the public network. Most PBX systems are
automated to allow users to dial a specified digit to obtain an outside line.
PING
Packet Internet Groper. A program useful for testing and debugging networks.
PING sends an echo packet to the specified host, waits for a response, and
reports success or failure and statistics about its operation.
POTS Plain Old Telephone Service. Refers to analog phone lines capable of making
and receiving telephone calls.
PPP
Point-to-Point Protocol. Protocol between the terminal and the router. A
communications protocol that provides dial-up access to the Internet. PPP
encapsulates common network-layer protocols in specialized Network
Control Protocol packets; for example IP over PPP (IPCP) and IPX over PPP
(IPXCP).
protocol
A formal set of rules developed by international standards bodies, LAN
equipment vendors, or groups governing the format, control, and timing of
network communications. A set of conventions dealing with transmissions
between two systems. Typically defines how to implement a group of services
in one or two layers of the OSI reference model. Protocols can describe
low-level details of machine-to-machine interfaces or high-level exchanges
between allocation programs.
PSTN
Public Switched Telephone Network. Refers to the international telephone
system based on copper wires carrying analog voice data.
QoS Quality of Service. A networking term that specifies a guaranteed level of
throughput.
repeater A network device used to regenerate or replicate a signal. In a data network, a
repeater can relay messages between subnetworks that use different protocols.