Lucent Technologies PacketStar PSAX, User Manual

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255-700-243 Glossary-43
PacketStar
®
PSAX 12-Port Medium-Density DS1 Multiservice Module User Guide , Issue 1 Release 8.0
Glossary
pinout A description or diagram of the pins of a chip or connector.
plain old telephone service See POTS.
PLAR private line, automatic ringdown. A leased voice circuit con-
necting two telephones. When either handset is lifted, the
other telephone rings automatically.
PLCP Physical Layer Convergence Protocol. Part of the physical
layer that adapts the transmission facility to handle Distrib-
uted Queue Dual Bus (DQDB) functions, used for DC-3 trans-
mission of ATM. ATM cells are encapsulated in a 125-micro-
second frame defined by the PLCP, which is defined within
the DS3 M-frame.
PNNI Private network-to-network interface. A routing information
protocol that enables extremely scalable, full function,
dynamic multivendor ATM switches to be integrated in the
same network.
PNNI topology state packets See PTSP.
point-to-multipoint A circuit by which a single signal goes from one origination
point to many destination points.
point-to-point protocol A protocol that connects two nodes (for example, router-to-
router and host-to-network) over both synchronous and
asynchronous circuits. PPP replaces Serial Line Interface Pro-
tocol (SLIP), an older protocol.
polling An access control method in which one master device, such
as a NMS, queries other network devices, and requests they
transmit one at a time.
POTS Plain Old Telephone Service. The basic service supplying stan-
dard, single-line telephones (with no features like call waiting
or call forwarding).
PRI Primary Rate Interface. The ISDN equivalent of a T1 circuit.
Delivered to the customer’s premises, it delivers 23 B+D at
1.544 Mbps. PRI enables IP connectivity to the PSTN.
PRI ISDN Integrated Services Digital Network with Primary Rate Inter-
face service. A network with 24 B (bearer) channels, each of
which is a full 64,000 bits per second. One of these channels
is typically used to carry signaling information for other 23
channels. In Europe, PRI ISDN is 30 bearer channels of 64
Kbps and two signaling channels, each of 64 Kbps.
primary rate interface See PRI.
PRI Offload A method for transferring internet data calls from a PSTN
5ESS switch to a PSAX, which sends them to ISP RAS’s and
world wide web switches. Since internet data calls are much
longer and have much bigger payloads than DS0 voice calls,
this transfer frees PSTN circuits for shorter voice calls and
relieves PSTN network congestion.
private automatic branch exchange See PBX.