Cabletron Systems SFCS-200BX - Manual (Page 172)

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GLOSSARY
OSI (Open Systems Interconnection) - the 7-layer suite of protocols
designed by ISO committees to be the international standard computer net-
work architecture.
OSPF (Open Shortest Path First) Protocol - a routing algorithm for IP that
incorporates least-cost, equal-cost, and load balancing.
Out-of-Band Management - refers to switch configuration via the serial port
or over Ethernet, not ATM.
Packet Switching - a communications paradigm in which packets (messages)
are individually routed between hosts with no previously established com-
munications path.
PBX (Private Branch Exchange) - a private phone system (switch) that con-
nects to the public telephone network and offers in-house connectivity. To
reach an outside line, the user must dial a digit like 8 or 9.
PCI (Peripheral Component Interconnect) - a local-bus standard created by
Intel.
PCM (Pulse Code Modulation) - a modulation scheme that samples the
information signals and transmits a series of coded pulses to represent the
data.
PDN (Public Data Network) - a network designed primarily for data trans-
mission and intended for sharing by many users from many organizations.
PDU (Protocol Data Unit) - a unit of data specified in a layer protocol and
consisting of protocol control information and layer user data.
Peak Cell Rate - at the PHY Layer SAP of a point-to-point VCC, the Peak Cell
Rate R
p
is the inverse of the minimum inter-arrival time T
0
of the request to
send an ATM-SDU.
Peer Entities - entities within the same layer.
PHY (Physical Layer) - the actual cards, wires, and/or fiber-optic cabling
used to connect computers, routers, and switches.