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ADC Telecommunications, Inc.
604 A
PPENDIX C: GLOSSARY
OSPF See Open Shortest Path First.
Packet Identifier
(PID)
A unique integer value used to identify elementary streams of a program in a
single- or multi-program MPEG-2 stream.
PHY See Physical Layer.
Physical (PHY)
Layer
Layer 1 in the Open System Interconnection (OSI) architecture. It provides
services to transmit bits or groups of bits over a transmission link between
open systems and which entails electrical, mechanical, and handshaking
procedures.
Physical Media
Dependent (PMD)
Sublayer
A sublayer of the Physical Layer that transmits bits or groups of bits over
particular types of transmission link between open systems. It entails
electrical, mechanical, and handshaking procedures.
PID See Packet Identifier.
PMD See Physical Media Dependent Sublayer.
Protocol A set of rules and formats that determines the communication behavior of
layer entities in the performance of the layer functions. It may still require an
authorization exchange with a policy module or external policy server prior
to admission.
PTR A record that contains a pointer to another part of the domain name space.
This record is typically used in reverse zones.
QAM See Quadrature Amplitude Modulation.
QoS See Quality of Service.
Quadrature
Amplitude
Modulation (QAM)
A method of modulating digital signals onto a radio-frequency carrier signal
involving both amplitude and phase coding. This achieves a higher data
transfer rate than just amplitude or phase modulation alone.
Quality of Service A networking term that specifies a guaranteed throughput level and end to
end latency for traffic on the network.
Radio Frequency
(RF)
Signals that are used by the CMTS transmitter and receiver to send data over
HFC network. A radio frequency carrier is modulated to encode the digital
data stream for transmission across the cable network.