Cabletron Systems 1800 User Manual

Page 434

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SmartSwitch 1800 4. 0 User G uide, Rev 01

PAD

stands for “packet assembler/disassembler,” which allows a non-X.25 device to access
a SmartSwitch 1800, by converting its protocol to the X.25 packet mode protocol, and
vice versa. SmartSwitch 1800 supports integral async, SNA, and BSC PADs.

PBX

stands for Private Branch Exchange, and refers to a small private telephone switch.

PDN

stands for “public data network,” which is a network operated by common carriers or
telecommunications administrations for the purpose of providing data transmission
capabilities to the public.

Physical DCE/DTE

see “DCE” and “DTE.”

Port

is the entry or exit point for node traffic.

Protocol

is an agreement on format, meaning, and relative timing of information exchanged
between two communications devices.

stands for “physical unit,” which is an IBM referenced to any SNA host or terminal
device.

Public Data Network

see “PDN.”

PVC

stands for “permanent virtual circuit,” which is a permanent logical connection
between two subscribers, analogous to a leased line. Transmission of packets on a
PVC needs no call setup or call clearing.

QLLC

is “Qualified Logical Link Control,” which is a method of encapsulating SNA traffic
for transmission over X.25.

RIP

stands for “routing information protocol,” which provides for dynamic routing in a
TCP/IP implementation.

Root

is the bridge determined (by implementation of the spanning tree algorithm) to be the
lowest-cost path between points in a bridged link.