Fore Systems forerunner series, Configuration Manual

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ForeRunner ATM Switch Network Configuration Manual
Glossary - 25
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Glossary
Optical Carrier level-n (OC-n) -
The optical counterpart of STS-n (the basic rate of 51.84 Mbps on
which SONET is based is referred to as OC-1 or STS-1).
Organizationally Unique Identifier (OUI) -
Part of RFC 1483. A three-octet field in the SubNet-
work Attachment Point (SNAP) header, identifying an organization which administers the
meaning of the following two octet Protocol Identifier (PID) field in the SNAP header.
Together they identify a distinct routed or bridged protocol.
Out-of-Band Management -
refers to switch configuration via the serial port or over Ethernet,
not ATM.
Out-of-Frame (OOF) -
a signal condition and alarm in which some or all framing bits are lost.
Packet -
An arbitrary collection of data grouped and transmitted with its user identification
over a shared facility.
Packet Assembler Disassembler (PAD) -
interface device that buffers data sent to/from charac-
ter mode devices, and assembles and disassembles the packets needed for X.25 operation.
Packet Internet Groper (ping) -
a program used to test reachability of destinations by sending
them an ICMP echo request and waiting for a reply.
Packet Level Protocol (PLP) -
Network layer protocol in the X.25 protocol stack. Sometimes
called X.25 Level 3 or X.25 Protocol.
Packet Switched Network (PSN) -
a network designed to carry data in the form of packets. The
packet and its format is internal to that network.
Packet Switching -
a communications paradigm in which packets (messages) are individually
routed between hosts with no previously established communications path.
Payload Scrambling -
a technique that eliminates certain bit patterns that may occur within an
ATM cell payload that could be misinterpreted by certain sensitive transmission equipment as
an alarm condition.
Payload Type (PT) -
bits 2...4 in the fourth byte of an ATM cell header. The PT indicates the type
of information carried by the cell. At this time, values 0...3 are used to identify various types of
user data, values 4 and 5 indicate management information, and values 6 and 7 are reserved
for future use.
Peak Cell Rate -
at the PHY Layer SAP of a point-to-point VCC, the Peak Cell Rate is the
inverse of the minimum inter-arrival time T0 of the request to send an ATM-SDU.
Peak Cell Rate (PCR) -
parameter defined by the ATM Forum for ATM traffic management. In
CBR transmissions, PCR determines how often data samples are sent. In ABR transmissions,
PCR determines the maximum value of the ACR.
Peer Entities -
entities within the same layer.
Peripheral Component Interconnect (PCI) -
a local-bus standard created by Intel.