Glossary
Acronyms
ACT
Active
ANSI
American National Standards Institute
ARAP
Apple Remote Access Protocol
ARP
Address Resolution Protocol
ASYNC
Asynchronous
AUI
Attachment Unit Interface
BOP
Bit Oriented Protocols
C
Compression
CCITT
International Consultative Committee for Telegraph
and Technology (Translation from French title)
CRC
Cyclic Redundancy Check
CRT
Cathode Ray Tube
CSU
Channel Service Unit
CTS
Clear to Send
DCD
Data Carrier Detect
DCE
Data Communications Equipment
DDS
Digital Data Service
DLC
Data Link Connection
DLCI
Data Link Connection Identifier
DSR
Data Set Ready
DSU
Data Service Unit
DTE
Data Terminal Equipment
DTR
Data Terminal Ready
E
Enhanced
EIA
Electronic Industries Association
ERR
Error
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GLOSSARY
Glossary-2
FRAD
Frame Relay Access Device
FTP
File Transfer Protocol
HDLC
High Level Data Link Control
HP
Hewlett Packard
I/O
Input/Output
IBM
International Business Machines
IE
Information Elements
IETF
Internet Engineering Task Force
IP
Internet Protocol
IPX
Internet Packet Exchange
ISDN
Integrated Services Digital Network
ISO
International Standards Organization
ITU
International Telecommunications Union
KBPS
KiloBits Per Second
L/B
Loopback
LADS
Local Area Data Set
LAN
Local Area Network
LAPB
Link Access Procedure Balanced
LCN
Logical Channel Number
LED
Light Emitting Diode
LMI
Local Management Interface
MAC
Media Access Control
NIC
Network Interface Card
NRZ
Non-Return to Zero
NRZI
Non-Return to Zero Inverted
NS
No Signal
OS
Out of Service
OSIRM
Open Systems Interconnection Reference Model
PPP
Point to Point Protocol
PVC
Permanent Virtual Circuit
RD
Receive Data
RFC
Request for Comment
RIP
Routing Information Protocol
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GLOSSARY
RLSD
Received Line Signal Detector
RM
Rack Mount
RS
Recommended Standard
RST
Reset
RTS
Request to Send
RXCLK
Receive Clock
SAP
Service Advertising Protocol
SD
Send Data
SDLC
Synchronous Data Link Control
SIMM
Single in Line Memory Module
SLIP
Serial Line Internet Protocol
SMT
Surface Mount Technology
SNA
Systems Network Architecture
SQE
Signal Quality Error
SVC
Switched Virtual Circuit
SYNC
Synchronous
TCP
Transmission Control Protocol
TD
Transmit Data
TDM
Time Division Multiplexing
TELCO
Telephone Company
TST
Test
TTL
Transistor Transistor Logic
TXCLK
Transmit Clock
UNI
User Network Interface
USOC
Universal Service Order Code
UTP
Unshielded Twisted Pair
UUCP
Unix to Unix Copy Program
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GLOSSARY
Terms
10BASE-2.
The IEEE standard for a 10 Megabit per second, baseband network on
thin coaxial cable.
10BASE-5 (THICK).
The IEEE standard for a 10 Megabit per second, baseband
network on thick coaxial cable.
10BASE-5 (THIN). The IEEE standard for a 10 Megabit per second, baseband network
on twisted-pair wiring.
AUI
Attachment Unit Interface. Drop cable between MAU and DTE.
BANDWIDTH.
The range of frequencies assigned to a communications channel.
‘Bandwidth’is often used to refer to the ability of a communication channel to carry
data, such as a ‘high-bandwidth channel’, which carries large quantities of data, and
a ‘low-bandwidth channel’, which carries small quantities of data.
BANDWIDTH MANAGER.
The term Bandwidth Manager applies to a range of
multiplexers which intelligently ‘manage’ the use of private-line bandwidth, rather
than just allocate it in a rigid way as with Time Division Multiplexing (TDM).
With fast packet switching, management of the bandwidth is automatic, but control
must still be imposed (in different ways to TDM), including the allocation of priority
e.g. voice, which needs to be carried across the network without interruption and
minimum delay.
Committed Burst size. The maximum amount of subscriber data that a network
agrees to transfer, under normal conditions, during a time interval Tc. Bc is
expressed in terms of bits.
BC
Excess Burst size. The maximum of uncommitted data in excess of Bc that the
network will attempt to deliver during a time interval Tc. Be is expressed in terms
of bits.
BE
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Backward Explicit Congestion Notification. A method by which the unit sets
a bit in the frame relay header, to notify the data source that congestion is occurring.
The BECN bit is set for frames coming in the direction opposite to the congestion
flow.
BECN
CALL.
A full duplex connection between any two ports or channels in an F10
network.
Code Excited Linear Prediction. An encoding technique which predicts the
voice waveform using a codebook of waveform shapes. This encoding allows low
bit rates to be used.
CELP
CHANNEL. A subrate (n x 64 kbit/s or n x 56 kbit/s) call within a G.704 or D4 framed
digital stream.
CIR Committed Information Rate. The CIR represents the user’s estimate for
“normal traffic” during a busy period. The CIR is used to determine whether
predetermined thresholds are being exceeded and packets may be discarded if the
CIR is exceeded.
DATAGRAM .
A means of sending data, in which parts of the message are sent in
random order and the recipient machine has the task of reassembling the parts in the
correct order. The unit of transmission in the network layer (such as IP). A datagram
may be encapsulated in one or more packets passed to the data link layer.
DCE Data
Circuit terminating Equipment. The equipment at the end of a data circuit
or telephone line that establishes, maintains, and terminates a connection within the
circuit. It converts signals between the data terminal equipment (DTE) and the data
circuit. See DTE.
DE Discard Eligibility. A bit in the frame relay header used for congestion control
of “burst” conditions.
Data Link Connection Identifier. A 10 bit address that indicates the Permanent
or switched Virtual Circuit (PVC) with which the data in the frame is associated.
Unless the network follows the optional Global Addressing convention, a DLCI
identifies a connection only on its local Frame Relay interface.
DLCI
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GLOSSARY
DTE Data Terminal Equipment. Any device that provides digital signals as its output.
To communicate over a data circuit, the DTE must be connected to Data Circuit
terminating Equipment (DCE).See DCE.
Dual Tone Multi Frequency. A telephone signalling method by which each
depressed key generates two audio output tones, the combination of which is unique
for each of the 12 keys. DTMF differs from decadic dialling as no “on-hook”, “offhook” are generated on the telephone line.
DTMF
These are the signals used to establish phone connections. The ‘E’leads
being an output from the voice card while the ‘M’ leads are inputs into the voice
card.
E&M LEADS.
ETHERNET.
A Local Area Network (LAN) specification that uses baseband
signalling at 10Mbps, provides multiple access to the transmission medium, and
requires that a transceiver be able to detect the presence of another transceiver (for
collision detection). These three requirements are abbreviated as Carrier Sense
Multiple Access with Collision Detection (CSMA/CD).
Federal Communications Commission. Regulatory authority in the United
States.
FCC
Frame Check Sequence. This is a 16 bit field which is added to the end of data
link frames. The FCS determines whether a frame was received without error.
FCS
Forward Explicit Congestion Notification. The unit sets a bit in the Frame
Relay header to notify the data destination that congestion is occurring. This is
useful for “destination controlled” protocols such as TCP/IP.
FECN
FLASHPAK.
A storage device that contains software for the F10 node. It may store
up to 2 versions of software. New versions of software may be stored in a flashpak
using Central Site Software Distribution (CSSD).
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FRAME (PPP).
The unit of transmission at the data link layer. A frame may include
a header and/or a trailer, along with some number of units of data.
FRAME RELAY.
Frame Relay is a simplification of the X.25 protocol, that runs over
faster transmission facilities. It is a two layer connection oriented protocol that
minimizes error recovery and flow control. Frame Relay can be used to provide
LAN-LAN and PABX-PABX connectivity.
FRONT CARD.
PCB providing some proportion of nodal functionality when
correctly inserted in shelf. Often referred to as just Card. Applicable only to F9300
products.
High level Data Link Control. A data link layer protocol in which data is
transmitted with a zero inserted after each consecutive group of five 1s, except for a
particular flag pattern, 01111110, that defines the beginning and the end of a frame.
HDLC
IAUISDN
ICMP
Attachment Unit. See ISDN.
Internet Control Message Protocol. A simple reporting protocol for IP.
INTERNET.
A large collection of connected networks running the Internet suite of
protocols. The Internet protocol stack has four layers:
1 - Interface, 2 - Internet, 3 - Transport, 4 - Application.
INTERNET ADDRESS. A unique TCP/IP 32 bit numeric identifier that encodes both
the network number and the number of a host on that network.
IP
Internet Protocol. Inter-networking protocol corresponding to OSI layer 3.
Interface Personality Module. The IPM dictates the type of interface (e.g. RS232, RS-422 etc.) for a particular data or voice port of the node.
IPM
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GLOSSARY
Integrated Services Digital Network. A telecommunications network that uses
both digital transmission and switching techniques to provide integrated voice and
data communications.
ISDN
ISO
International Standards Organization. A world organization that sets standards.
ITU-T. International Telecommunications Union - Technical sector. Formerly known
as CCITT
Local Area Network. A term used to describe computers and other devices
connected to each other in a building. LANs enable people to share printers and send
data such as electronic mail or files to each other.
LAN
LBRV Low
Bit Rate Voice. Voice calls with speeds between 4.8k and 16k, using the
CELP scheme.This is used by GS2 cards when they are equipped with LBRV
modules.
Light Emitting Diode. Illuminated displays used mostly for displaying card
status.
LED
MAC.
Media Access Control.
MAU
Media Access Unit. Transceiver of packets on an Ethernet, (IEEE 802.3).
Network Control System. The supervisor is a program that runs in every node,
controlling that node and its communication with other nodes. The supervisor
supports the user interface - the Network Control System (NCS).
NCS
Network Control Terminal. A VT 100 or VT 225 terminal, or personal
computer connected into a supervisor port. The personal computer needs to emulate
a VT 100 or VT 225 terminal. The VT100 format provides a monochrome display
and the VT 225 provides a color display.
NCT
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NETWORK.
A collection of sub-networks connected by intermediate systems and
populated by end- systems, also (Internet usage) a single subnetwork or a related set
of sub-networks in the OSI sense.
NODE.
A collection of ports concentrated at one site, collecting data for
transportation to a remote location. Numerous ports are multiplexed into at least one
high capacity trunk for transport to another node. Multi-trunk port switch,
supporting up to 16 trunk connections to other nodes.
NVRAMPAK.A
storage device that may contain a node’s database configuration.
NVRAMpaks may be saved and restored via the NVRAM command.
Open Systems Interconnection. A seven layer reference model of data
communication protocols, drafted by the International Standards Organization
(ISO).
OSI
PACKET (PPP).
The basic unit of encapsulation, which is passed across the interface
between the network layer and the data link layer. A packet is usually mapped to a
frame; the exceptions are when data link layer fragmentation is being performed, or
when multiple packets are incorporated into a single frame.
PACKET SWITCHING .
A data communications technique in which the packets of data
are transmitted by means of a datagram on a virtual circuit. The transmission
channel is only occupied for the duration of the packet transmission.
Private Automatic Branch Exchange. This is an automated telephone
switching system serving an organization. It is located in the organization’s
premises and connects to the public telephone network.
PABX
PEER (PPP).
The other end of the point-to-point link.
PING Packet Internet Groper. An ICMP (see ICMP) echo request packet sent to an
IP address to test its general health.
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GLOSSARY
PORT.
The physical termination point of a card for connection to external
equipment.
PROTOCOL.
A set of rules governing the format, timing, sequencing and error
control of messages exchanged between communication entities in a network.
Public Switched Telephone Network. The public phone system of a country.
Use of this system is governed by Regulatory Authorities in each country.
PSTN
REAR CARD. PCB connecting from rear of shelf to backplane and front card.
Provides termination to port connectors or mass termination scheme. Some versions
contain line isolation and matching componentry.
RING/FEED.
The ‘ring’ signal is the voltage (90VAC) to allow telephones to ring
while the ‘feed’ signal is the voltage (-50VDC) to enable the voice signal to
propagate throughout the telephone system.
ROUTE.
Path taken through a network by a call.
ROUTER.
A device that connects multiple networks together and forwards packets
between them. A router operates at layer 3 of the OSI reference model. Also known
as a network relay.
SDLC Synchronous Data Link Control. This is a communication protocol developed
by IBM which is associated with IBM’s Systems Network Architecture (SNA). The
SDLC is used in transferring data across various network configurations using bit
synchronous data transmission techniques. SDLC initiates, checks, controls and
terminates information exchanges on communication lines, and is designed for fullduplex operation.
SHELF.
Card cage or chassis used to house the PSU, cooling fans, common logic,
port and trunk cards of a node.
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SILENTLY DISCARD (PPP).
The implementation discards the packet without further
processing. The implementation SHOULD provide the capability of logging the
error, including the contents of the silently discarded packet, and SHOULD record
the event in a statistics counter.
Simple Network Management Protocol. A network monitoring protocol for
TCP/IP based networks which was developed by the International Standards
Organization (ISO). This is a connectionless protocol.
SNMP
SUPERVISOR . A program that runs in every node, controlling that node and its
communications with other nodes. The supervisor supports the user interface.
TC Committed rate measurement interval. The time interval during which the user is
allowed to send Bc committed amount of data, or, Bc committed amount of data +
Be excess amount of data.
Tc is calculated using the formula, Tc = Bc / CIR
TDM
.Time Division Multiplexing.
TNV.
Telecom Network Voltage.
TRUNK.
A multiplexed connection between two nodes.
TOPOLOGY.
The layout of the F10/F5/F3 network. The way the nodes connect
together.
VIRTUAL CHANNEL.
The timeslot that the port occupies on an F10 trunk or F10
backplane.
VSTN.
Virtual Switched Telephone Network. VSTN numbers are used to specify
voice destination ports. The user can initiate a connection to a voice port by dialling
its VSTN number.
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GLOSSARY
WAN.
Wide Area Network.
WORLD MODEL. Dynamic database that is held in each node keeping an up to date
image of the entire network.
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