3Com Nbx 100 And Ss3 Nbx Administration Guide

							GLOSSARY471
intelligent hubSee managed hub.
IPInternet Protocol. The TCP/IP standard protocol that defines the IP 
datagram as the unit of information passed across an Internet. IP provides 
the basis for connectionless packet delivery service.
IP addressThe address used by devices on the network to establish their unique 
identity. IP addresses are composed of four fields separated by dots. Each 
field is an 8-bit number (0 through 255). IP addresses can be permanently 
assigned, or they can be temporarily assigned by DHCP
.
IP telephonyTechnology that allows voice, data, and video to be transmitted over 
IP-based networks.
ISDNIntegrated Services Digital Network. An international telecommunications 
standard for transmitting voice, video and data over digital lines running 
at 64 Kbit/s. ISDN uses B channels, or “bearer” channels, to carry voice 
and data. It uses a separate D channel, or “delta,” channel for control 
signals to the telephone company computer.
ITUInternational Telecommunication Union. An international standards 
organization for telecommunications.
jitterThe variation in latency (waiting time) for different packets on the 
network. For real time data such as voice transmission, jitter must be kept 
to a minimum.
key modeA telephone system operating model in which each telephone in the 
system has buttons for each available outside line. Also known as a 
square plan or a direct system inward access (DISA) system. See also 
hybrid mode
.
LANlocal area network. A communications system that links computers, 
printers, and other devices. LANs allow users to communicate and share 
resources like hard disk storage and printers. Devices linked by a LAN may 
be on the same floor or within a building or campus. 
LAN segmentA section of a local area network that is used by a particular workgroup or 
department and separated from the rest of the LAN by a bridge, router or 
switch. 
LAN switchA network device that connects stations or LAN segments, also known as 
a frame switch.  
						

							472GLOSSARY
latencyThe sum of all the delays in an end-to-end connection.
layeringThe process of dividing complex software up into several layers, each of 
which performs a specific task. Layering allows faster and easier software 
development and is often used in public, open software.
LCDLiquid Crystal Display. A low cost display technology. 
LLCLogical Link Control. A data link protocol for LANs that is part of the IEEE 
802.2 standard and common to all LAN standards for OSI model data 
link, level two transmissions.
loop startThe most common signaling method in the public telephone network, 
typically used for residence and business CO
 lines.
MACMedia Access Control. A sub-layer of the Data Link layer (Layer 2) of the 
ISO OSI model
 responsible for media control. Also known as the “MAC 
layer.” 
MAC addressA unique 48-bit number that is encoded in the circuitry of a device to 
identify it on a LAN. Also known as a “hardware address” or an 
“Ethernet
 address.” 
managed hubA network device in which each port on the hub can be configured, 
monitored, and enabled or disabled by a network administrator from a 
hub management console or utility tied into an SNMP (Signaling Network 
Management Protocol) platform. Hub management can also include 
gathering information on network parameters.
MAUMedium Attachment Unit. A transceiver that provides the correct 
electrical or optical connection between the computer and IEEE 802.3 
LAN media.
MIBManagement Information Base. A database that can be accessed by a 
gateway running CMIP (Common Management Information Protocol), 
CMOT (CMIP Over TCP/IP), or SNMP (Signaling Network Management 
Protocol) network management protocols. The MIB defines variables 
needed by the protocol to monitor and control components in a network. 
Managers can fetch or store these variables.
modem MOdulator/DEModulator. A modem converts a binary bit stream to an 
analog signal and vice versa. 
						

							GLOSSARY473
multiplexerA device that can send several signals over a single line. A similar device 
at the other end of the link then separates the signals. 
multi-taskingThe concurrent execution of two or more tasks or the concurrent use of a 
single program that can carry out many functions.
NCPNetwork Call Processor. The device that manages call traffic, voice mail, 
the Auto Attendant, and related applications in an NBX system.
NetBEUINetBios Extended User Interface. A network device driver or transport 
protocol that is the transport driver supplied with LAN Manager. 
NetBiosNetwork Basic Input/Output System. Software developed by IBM that 
provides the interface between the PC operating system, the I/O bus, and 
the network. Since its design, NetBIOS has become a de facto standard.
NetWareLAN Network Operating System and related products developed by 
Novell. NetWare is based on the SPX/IPX networking protocols.
network collisionsResult of two stations simultaneously attempting to use a shared 
transmission medium. See collision
.
network congestionResult of increased network utilization. Creates traffic bottlenecks on 
a LAN segment. See congestion
.
network layerLayer 3 in the OSI model
 responsible for the routing and relaying through 
one or more networks in multiple link or wide area environments.
network
managementThe process and technique of remotely or locally monitoring and 
configuring networks.
network pingA packet transfer that checks logical continuity between a PC and a 
specified IP address.
NICNetwork Interface Card. Controller circuitry that connects a node to a 
network, usually in the form of a card in a PC expansion slot. In 
conjunction with the NOS (Network Operating System) and PC operating 
system, it helps transmit and receive messages on the network.
nodeDevice on a network that demands or supplies services. Also, a location 
where transmission paths are connected.  
						

							474GLOSSARY
NOSNetwork Operating System. Software that connects all the devices on a 
network so that resources can be shared efficiently and managed from a 
central location. Novell NetWare is one example of a network operating 
system.
OEMOriginal Equipment Manufacturer. The maker of a product or component 
that is marketed by another vendor, integrator, VAR (Value Added 
Reseller), or reseller. 
off-hookThe state of a telephone line that allows dialing and transmission but 
prohibits incoming calls from being answered. The term stems from the 
days when a telephone handset was lifted off of a hook. Contrast with 
on-hook.
off-site notificationA feature that sends a message to a pager, outside telephone number, or 
email account that informs a user of a voice mail message. The user can 
retrieve the messages remotely.
on-hookThe state of a telephone line that can receive an incoming call. 
OSI modelA conceptual model of hardware and software layers that define when, 
how, and in what order data can be transmitted on a network. The OSI 
Model defines seven layers:
out-of-band signalingAn extra signal transmitted with the information signal to monitor and 
control a transmission. It provides an additional layer of resilience by using 
a separate channel.
packetA collection of bits, including address, data, and control information, that 
are transmitted together. The terms frame and packet are often used 
synonymously. 
packet bufferMemory space reserved for storing a packet awaiting transmission or for 
storing a received packet. 
Layer 7Application layer
Layer 6Presentation layer
Layer 5Session layer
Layer 4Transport layer
Layer 3Network layer
Layer 2Data Link layer
Layer 1Physical layer 
						

							GLOSSARY475
packet switchingA method of switching data in a network. Individual packets of a set size 
and format are accepted by the network and delivered to their 
destination. The sequence of packets is maintained, and destination 
established, by the exchange of control information (also contained in the 
packets) between the sending terminal and the network before the 
transmission starts. 
paging1) A communications service that includes a one-way beeper service, 
one-way text service, and two-way text and voice service.
2) A public address announcement system. Many PBX
 telephone systems 
can do paging through the speakers in the telephone sets. 
PBXPrivate Branch eXchange. An in-house telephone switching system that 
interconnects telephone extensions to each other, as well as to the 
outside telephone network. It can include functions such as least cost 
routing for outside calls, call forwarding, conference calling, and call 
accounting.
PCSPersonal Communications Services. Refers to a variety of wireless services 
emerging after the U.S. Government auctioned commercial licenses in 
late 1994 and early 1995.
phantom mailboxA user profile that uses a telephone number with no associated 
telephone. Messages can be sent to the phantom mailbox from within 
the voice mail system. The Auto Attendant can route messages to the 
phantom mailbox, and you can dial the phantom mailbox directly.
portA computer interface capable of attachment to another device, such as a 
modem for communicating with a remote terminal or, if the port is within 
a hub, to a workstation. 
POTSPlain Old Telephone Service. 
PPPPoint-to-Point Protocol. An addition to the Internet protocol suite to help 
connect devices where dissimilar transport protocols exist. Typically used 
for serial connections to the Internet.
predictive dialingAutomated dialing feature in which CTI
 software predicts when you will 
end your current call, and dials the next call in advance.
pretranslatorA device that interprets and modifies a sequence of incoming digits or 
transmits outgoing digits. 
						

							476GLOSSARY
preview dialingAutomated dialing feature in which CTI software queues the next call to 
be made but allows you to check and activate the call. 
PRIPrimary Rate Interface. An ISDN service for users with large bandwidth 
requirements, such as large PBXs or high performance video desktop 
conferencing systems; the ISDN equivalent of a T1 circuit. 
protocolA set of rules governing the information flow within a communications 
infrastructure. A protocol typically specifies the structure of parameters 
like format, timing, and error correction.
protocol converterA device that translates between two protocols to facilitate 
communications between different computers or different systems.
PSTNPublic-Switched Telephone Network. The term that describes the national 
telephone network. 
punch-down blockTelephony term describing the connector arrangements for distributing 
and connecting unshielded and shielded twisted pair wiring inside a 
building. Typically found in telephone wiring closets.
Q.921/931ITU-TS “Q Series” Recommendations describing Lap-D, the Layer 2 
protocol for an ISDN D-channel. See OSI model
.
reconfigurationThe process of physically altering the location or functionality of network 
or system elements. Automatic configuration describes the way 
sophisticated networks can readjust themselves in the event of a link or 
device failing, enabling the network to continue operation.
redundancyIn data transmission, this refers to characters and bits that can be 
removed from a transmission without affecting the message. In data 
processing and data communications, it means providing backup for 
components so that if one of them fails, the system continues to run 
without interruption. 
RENRinger Equivalency Number. A number that indicates how much power is 
required by a telephone to make it ring. When connecting telephones to 
a telephone line, the sum of the RENs of the telephones must be less than 
the rated REN capacity of the telephone line.
repeaterA device that extends the maximum length of cable that can be used in a 
single network. 
						

							GLOSSARY477
RMONRemote Monitoring. A facet of SNMP-based network management, the 
RMON MIB (Management Information Base) defines the standard 
network monitoring functions for communication between SNMP-based 
management consoles and remote monitors. A typical MIB captures 
information about a device, but RMON captures information about traffic 
between devices. 
RJ-11A four-wire modular connector used by the telephone system. 
RJ-45An eight-wire modular connector used by telephone systems. The 
eight-pin modular connectors used for 10BASE-T UTP
 cable resemble 
RJ-45 connectors, but they have substantially different electrical 
properties. 
routerA network device that links LANs together locally or remotely as part of a 
WAN. A network built using routers is often termed an internetwork. 
routingThe process of delivering a packet across one or more networks via the 
most appropriate path. 
SASystem Appearance
screen POPA CTI
 term for a window that automatically opens on a user’s computer 
when a predefined telephone event occurs. For example, an incoming call 
could generate a screen pop that lists caller ID
 information.
segmentA LAN term meaning an electrically continuous piece of the bus. 
Segments can be joined together using repeaters or bridge
s. 
serial interfaceHardware for sending and receiving data one bit at a time. 
SMDRStation Message Detail Recording. A stream of call data from the 
telephone system. Typically, the data is not stored on the telephone 
system itself. Rather, it is captured by an external device that connects to 
the telephone system through an RS232 port.
SMTPSimple Mail Transfer Protocol. The TCP/IP
 standard protocol for 
transferring electronic mail messages from one machine to another. SMTP 
specifies how two mail systems interact and the format of control 
messages they exchange to transfer mail. 
SNASystems Network Architecture. IBM’s layered communications protocol 
for sending data between IBM hardware and software.  
						

							478GLOSSARY
STPShielded Twisted Pair. A twisted pair of wires surrounded by a shield that 
is typically made of braided wire or metal foil.
switched EthernetAn Ethernet network that allows each user the full Ethernet bandwidth of 
10 Mbit/s to another node. 
system-wide
greetingsA special type of time-dependent greeting that is used throughout the 
system.
T1/E1A high-speed data channel that can handle 24 voice or data channels (T1) 
or 30 voice or data channels (E1) at 64Kbit/s. Refers to the U.S. T1 line or 
European E1 equivalent.
T3A U.S. standard for high-speed data transmission at 44.736 Mbit/s, 
providing the equivalent bandwidth of 28 T-1 circuits. The carrier channel 
can handle 672 voice or data channels.
TA P ITelephony Applications Programming Interface
A Microsoft Windows standard interface for integration between 
telephone systems and Windows-based software. A typical example is 
integrating Caller ID with a database on your computer that contains 
detailed information about potential callers. When your telephone rings, 
a window pops up on your computer with information about the caller.
TCP/IPTransmission Control Protocol/Internet Protocol. The suite of protocols 
that define how to move information over the Internet. 
thin EthernetAn 802.3 LAN that uses smaller than normal diameter coaxial cable
; often 
used to link PCs together. Also known as 10BASE2
.
time-dependent
greetingGreetings that usually indicate the time of day that the caller is calling 
(morning, afternoon, evening) and are an optional feature of the 
Automated Attendant.
token ringA communications protocol in which a special data packet, called a 
token, is passed from node to node on the network ring. Only the 
terminal or workstation that currently has the token can transmit data.
toll-freeThe U.S. term for “free phone.”
toll restrictionsThe U.S. term for “call barring.” 
						

							GLOSSARY479
translationThe process of interpreting or modifying dialed digits for incoming or 
outgoing calls and allows the call to progress through the network. 
trunkA communications channel between two points. It often refers to 
large-bandwidth telephone channels between major switching centers, 
capable of transmitting many simultaneous voice and data signals.
twisted pairTwo insulated wires twisted together with the twists varied in length to 
reduce potential signal interference between the pairs. Twisted pair is the 
most common medium for connecting telephones, computers and 
terminals.
UPSUninterruptible Power Supply. A secondary power source attached to a 
piece of hardware, for example a server, which provides backup power 
for conducting an orderly shutdown if the server’s normal power supply 
fails.
UTPUnshielded Twisted Pair. Two insulated wires twisted together with the 
twists varied in length to reduce potential signal interference between the 
pairs. The standard cabling used for telephone lines and Ethernet 
10BASE-T.
virtual LANA logical, rather than a physical, LAN that includes workgroups drawn 
together for business reasons or for a particular project regardless of the 
location of the members. 
VPIMVoice Profile for Internet Mail. A set of Internet protocols that merges 
voice messaging and e-mail. VPIM lets voice mail and e-mail servers 
exchange messages across TCP/IP-based intranets and the Internet.
VTLVirtual Tie LIne. Allows several NBX domains to create tie lines on 
demand and to place calls over a WAN
. Uses peer-to-peer connections for 
the audio.
WANWide Area Network. A network that covers a larger geographical area 
than a LAN. In a WAN, telecommunications links are normally leased from 
the appropriate Public Telephone Operator (PTO). 
wiring closetThe location, usually a physical box, in which the cabling on one floor of a 
building is terminated.
workstationAnother name for a computer, typically running UNIX or the Windows NT 
operating system. 
						

							480GLOSSARY