1
10-100
10/100
10BASE-T
10BASE2
10BASE5
10BASE-FL
100BASE-FX
100BASE-TX
56K
(Or 10+100)
Refers to a device having both 10Mbps Ethernet and 100Mbps Fast Ethernet
connections, on separate ports. This is in contrast to 10/100, which has
connections on the same port.
See also 10/100, auto
negotiation, Ethernet,
Fast Ethernet, Mbps,
port.
10/100
Refers to a device having both a 10Mbps Ethernet and 100Mbps
Fast Ethernet connection on the same port. This is in contrast to 10-100,
which has both connections on different ports.
See also 10-100, auto
negotiation, Ethernet,
Fast Ethernet, Mbps,
port.
10BASE-T
This is a technical specification used for Ethernet networks.
10BASE-T is part of the IEEE standards body specification for Ethernet
(10Mbps) over Category 3, 4 or 5 twisted pair cable (two pairs of wire—one
pair for transmitting data and the other for receiving data). 10BASE-T
has a distance limit of approximately 100m (328ft) per segment.
See also Category
3 cabling, Category
5 cabling, Ethernet,
IEEE, Mbps,
network, segment,
STP, twisted
pair, UTP.
10BASE2
This is a technical specification used in Ethernet networks.
10BASE2 is part of the IEEE standards body specification for 10Mbps Ethernet,
and is thin coaxial cable, also known as thinnet or cheapernet.
10BASE2 has a distance limit of approximately 185m (607ft) per segment.
See also coaxial cable,
Ethernet, IEEE,
Mbps, network,
segment.
10BASE5
This is a technical specification used in Ethernet networks.
10BASE5 is part of the IEEE standard body specification for 10Mbps Ethernet,
and is thick coaxial cable. 10BASE5 has a distance limit of approximately
500m (1640ft) per segment.
See also coaxial cable,
Ethernet, IEEE,
Mbps, network,
segment.
10BASE-FL
This is a technical specification used in Ethernet networks.
10BASE-FL is part of the IEEE standards body specification for using fiber-optic
cabling that runs at 10Mbps (Ethernet). Segments in a network using 10BASE-FL
cabling can be up to 2km (1.24 mile) long.
See also fiber-optic
cable, IEEE, Mbps,
network, segment.
100BASE-FX
This is a technical specification used in Fast Ethernet
networks. 100BASE-FX is part of the IEEE standards body specification
for using fiber-optic cabling that runs at 100Mbps (Fast Ethernet).
See also Ethernet, Fast
Ethernet, fiber-optic
cable, IEEE, Mbps,
network.
100BASE-TX
This is a technical specification used in Fast Ethernet
networks. 100BASE-TX is part of the IEEE standards body specification
for 100Mbps (Fast Ethernet) Category 5 UTP (unshielded twisted pair) or
STP (shielded twisted pair) cable (two pairs of wire—one pair for
transmitting data and the other for receiving data).
See also Category
5 cabling, Ethernet,
Fast Ethernet, IEEE,
Mbps, network,
STP, UTP.
56K
The designation used to describe a device compatible with
the V.90 ITU standard for 56 Kbps downloads.
See also Kbps,
ITU.
access
point
adapter
card
ADSL
Alert LED
analog signals
Asynchronous Transfer
Mode
ATM
AUI
auto negotiation
auto sensing
An access point serves the same functions in a wireless network as a hub does in a cabled network. The access point
- Manages wireless network traffic
- Provides a bridge between the Ethernet-wired LAN and wireless service areas.
The access point uses high data rate, direct sequence spread spectrum technology to communicate with mobile and stationary units at distances of up to 300 feet (91 meters), providing high-capacity networking capability and mobility to end users.
adapter
card
Adapter cards are also referred to as NICs.
See NIC
for more information.
ADSL
Asymmetrical
Digital Subscriber Line. A telephone line that handles
high-speed data. The "asymmetrical" part means uneven transmission
rates from customer to telephone company up to
640 Kbps, and
from telephone company to customer at 1.544 to
6.1 Mbps.
See also DSL, Kbps, Mbps, xDSL.
Alert
LED
On all OfficeConnect devices, there are a series of LEDs
(light emitting diodes) that provide status information about the device.
On OfficeConnect devices, the Alert LED alerts you to abnormal network
conditions and is shaped like an exclamation mark (!).
See also hub, LED,
network, OfficeConnect.
analog
signals
Data that has been encoded as a continuous wave form for
transmission over phone lines.
See also modem.
Asynchronous
Transfer Mode (ATM)
A transmission mode in which information is organized in
cells. These cells are 53 bytes in length and are switched in a network
through virtual connections. An ATM network uses these virtual connections
to relay the traffic through high-speed switches from the sending customer
premise equipment (CPE) to the receiving customer premise equipment.
See also byte,
switch,
traffic.
See Asynchronous
Transfer Mode.
AUI
Attachment Unit Interface. This is
an IEEE 802.3 (Ethernet) standard interface that allows you to connect
a PC or an Ethernet device to an Ethernet network. For example, an OfficeConnect
device with an AUI port can be connected using a transceiver to an Ethernet
network running on thick coaxial cabling. Your PC may have a NIC (network
interface card) with a 15-pin AUI socket.
See also Ethernet, IEEE,
network, NIC,
OfficeConnect, PC,
transceiver.
auto negotiation
Some devices in the OfficeConnect range support auto negotiation.
Auto negotiation is where two devices sharing a link, automatically configure
to use the best common speed. The order of preference (best first) is:
100BASE-TX full duplex, 100BASE-TX half duplex, 10BASE-T full duplex,
and 10BASE-T half duplex. Auto negotiation is defined in the IEEE 802.3
standard for Ethernet and is an operation that takes place in a few milliseconds.
See also 100BASE-TX,
10BASE-T, duplex,
full duplex, half
duplex, IEEE, network,
OfficeConnect.
auto sensing
Some devices in the OfficeConnect range support auto sensing.
This is where a port that can operate at different speeds (for example,
10Mbps and 100Mbps) has the ability to detect the speed of another port
to which it is connected; both ports will automatically configure to use
the best common speed. The term has become interchangeable with auto
negotiation, which is similar.
See also auto negotiation,
Mbps, OfficeConnect,
port.
backbone
bandwidth
baud
B Channel
bit
bit rate
BNC
bps
BRI
bridge
broadcast
broadcast storm
byte
backbone
The main cable that connects network segments. A cable
that carries information between relatively remote devices, for example
between two hubs on opposite sides of a building.
See also hub, segment.
bandwidth
Bandwidth is a measure of the information capacity of a
communication link. For example, Ethernet has a bandwidth of 10Mbps.
Workstations or network users that use the network heavily are referred
to as using a high bandwidth—these are usually users who do
a lot of graphical or multi-media work across the network.
Bandwidth is the difference between the highest and lowest frequencies
of a communication link, expressed in Hertz (Hz).
See also Ethernet, Mbps,
network.
baud
This is the signalling rate of a line, in other
words, the rate at which data travels along a line. Baud is the number
of transitions (voltage or frequency changes) made per second.
See also bps.
B
channel
Bearer Channel. In ISDN communications, a B channel transmits
communications at 64 Kbps.
See also D channel,
Kbps,
ISDN.
bit
Binary digit. This is the smallest element
of computer information. A single digit in a binary number (0 or 1) is
a bit. Groups of bits make up larger units of data in computer systems—the
most commonly known is the byte (eight bits).
See also bps, byte.
bit rate
The speed at which bits are transmitted, usually expressed
in bits per second (bps).
See also bps,
bit.
BNC
British Naval Connector. BNC connectors
are used to connect, extend or terminate coaxial cable networks, such
as Ethernet. Some OfficeConnect hubs have a BNC port.
There are various connectors, such as the BNC T-connector, the BNC barrel
connector and the BNC terminator.
See also 10BASE2, coaxial cable, OfficeConnect, port, transceiver.
bps
bits per second. bps is used as a
measurement for transmission of data in a communications system.
See also bit,
Kbps,
Mbps.
BRI
Basic Rate Interface. A BRI line is one of two access
methods for ISDN; PRI (Primary Rate Interface), which is high speed, is
the other. Each BRI consists of two 64 Kbps B channels and one 16 Kbps
D channel per ISDN line.
See also B channel,
D channel,
ISDN,
PRI.
bridge
Bridges provide a way to join two or more networks together
to form a single logical network, and are similar to switches. The networks
that are joined together are referred to as network segments in
the resulting network. Bridges can connect LANs of a different network
type, for example, Ethernet to Fast Ethernet, or Ethernet to Token Ring.
Bridges can be installed into networks for the following reasons:
To increase the size or number of nodes for the entire network.
To reduce traffic bottlenecks caused by an excessive number of nodes.
To link different types of network, such as Ethernet and Token Ring, and
forward packets between them.
See also Ethernet, Fast
Ethernet, LAN,
network,
node,
packet,
segment,
switch,
Token
Ring, traffic.
broadcast
A data packet forwarded by a device to all nodes on a network,
or broadcast domain.
See also broadcast
storm, multicast,
network,
packet,
unicast.
broadcast storm
Multiple simultaneous broadcasts that typically absorb available network
bandwidth and can cause a network to slow down or become unusable. A broadcast
storm may occur, for example, due to faulty network equipment.
See also bandwidth,
broadcast,
network.
byte
A unit of data equivalent to eight binary digits (bits).
A byte holds the equivalent of a single character, such as a letter of
the alphabet (a) or an ampersand (&). Measurements on storage
devices, such as disks and databases, are given in bytes.
See also bit.
cable
modem
Card Services
Cat3 cable
Cat5 cable
Category 3 cabling
Category 5 cabling
CHAP
Class I/II
Class A/B Certification
client
client/server
client/server network
coax
coaxial cable
collision
COM port
compression
congestion
cross-over cable
crosstalk
CSMA/CD
A modem used to connect
a computer to a cable TV system that offers online services.
See also modem.
Card
Services
Card Services in Windows 95 and Windows 98 provides Plug-and-Play
functionality for PCMCIA cards.
See also PCMCIA.
Cat3
cable
See also Category
3 cabling.
Cat5 cable
See also Category
5 cabling.
Category
3 cabling
One of five grades of twisted pair (TP) cabling defined
by the EIA/TIA-586 standard. Category 3 is voice grade cable used in 10BASE-T
networks (Ethernet) to transmit data at speeds of up to 10Mbps.
See also 10BASE-T, Category
5 cabling, EIA,
Ethernet,
Fast
Ethernet, Mbps,
network,
TIA,
twisted
pair.
Category
5 cabling
One of five grades of twisted pair cabling defined by the EIA/TIA-586
standard. Category 5 is used in 100BASE-T networks (Fast Ethernet) and
can transmit data up to speeds of 100Mbps. Category 5 cabling is better
to use for network cabling than Category 3, because it supports both Ethernet
(10Mbps) and Fast Ethernet (100Mbps) speeds.
See also 100BASE-T, Category
3 cabling, EIA,
Ethernet,
Fast
Ethernet, Mbps,
network,
TIA,
twisted
pair.
CHAP
Challenge Handshake Authentication
Protocol. The protocol used to verify a username and password during
PPP connections.
See also PAP, PPP.
Class
I/II
According to rules that define Fast Ethernet networks (IEEE
802.3u), networking devices are classified. All 3Com Fast Ethernet
OfficeConnect hubs are Class II. This means that two Class II hubs can
be directly connected together; Class I hubs cannot.
See also Ethernet, Fast
Ethernet, hub,
IEEE,
OfficeConnect.
Class A/B Certification
This is the FCC (Federal Communications Commission) certification of radiation
limits applied to digital devices. Class A is for business use. Class
B is for residential use and is more stringent in order to avoid interference
with televisions and other receiving devices. All OfficeConnect devices
have both Class A and B certification.
See also FCC, OfficeConnect.
client
A computer system or workstation that requests a service
or the contents of a file from a file server.
See also client/server,
client/server
network, server.
client/server
A network architecture whereby a system is divided into
two parts: the client (front end) is a requesting machine (usually a PC),
and the server (back end) is a supplying machine. Both terms can be applied
to hardware devices or software programs.
See also client, client/server
network, network,
server.
client/server
network
A local area network (LAN) structure in which network resources
are centralized and controlled from one or more servers. Individual workstations
or clients (such as PCs) must request services through the server(s).
See also client, client/server,
LAN,
network,
PC,
peer-to-peer network,
server,
traffic.
coax
See also coaxial
cable.
coaxial cable
This is a high-capacity networking cable. Coaxial cable
(or coax) consists of a hollow outer braided copper or foil shield
surrounding a single inner copper conductor with plastic insulation between
the two conducting layers. Coaxial cable is used for both broadband (for
example, cable TV) and baseband (for example, Ethernet) communications
networks. Coaxial cable is usually free from external interference and
capable of high transmission rates over long distances.
See also network, STP,
UTP.
collision
A term used to describe two colliding packets in an Ethernet
or Fast Ethernet network. Collisions are a part of normal Ethernet or
Fast Ethernet operation, but a sudden prolonged increase in the number
of collisions can indicate a problem with a device, particularly if they
are not accompanied by a general increase in traffic. On coaxial segments,
an increase in collisions can indicate faulty cabling.
See also coaxial cable,
Ethernet,
Fast
Ethernet, packet,
traffic.
COM
port
The serial communications port on a Windows-compatible
PC.
A reduction in size of a data set to lower the bandwidth or space required for transmission or storage.
congestion
Excessive network traffic.
See also network, traffic.
cross-over cable
A cross-over cable has its transmit and receive wires crossed.
For a connection between two devices to work, the receiver of one device
must be connected to the transmitter of the other.
Therefore, when connecting two MDI ports or two MDI-X ports, a cross-over
cable must be used.
See also EIA/TIA-232,
MDI,
PC,
port.
crosstalk
Interference on a cable or piece of equipment created
by a signal in an adjacent cable or piece of equipment. Crosstalk can
affect the quality of data transmission.
CSMA/CD
Carrier-sense Multiple Access
with Collision Detection. This is the protocol defined in
Ethernet and Fast Ethernet standards (IEEE 802.3) in which devices transmit
only after finding a data channel clear for a period of time. When two
devices transmit simultaneously, a collision occurs and the devices involved
in the collision delay retransmitting for a random length of time.
See also collision,
Ethernet,
Fast Ethernet,
IEEE,
protocol.
datagram
DBA
D channel
DHCP
distributed intelligence
DMZ
DNS
domain name
DoS
DOS
driver
DSL
Dual Speed Hub
duplex
duplex cable
datagram
A TCP/IP or IPX message that contains Internet source and
destination addresses and data which is used to route the packet through
a network. Datagrams are the primary information units used on the Internet.
See also Internet, TCP/IP.
DBA
Dynamic Bandwidth Allocation. DBA is a method of
reallocating bandwidth (such as a B channel) automatically. DBA allows
you to place or receive a voice call while a Multilink PPP call is active.
See also bandwidth,
B
channel,
Multilink PPP.
D
channel
The signaling channel on an ISDN line used to carry messages
between an ISDN modem and the public switch. It runs at either 16 or 64
Kbps.
See also B channel, ISDN,
Kbps.
DHCP
Dynamic Host Configuration Protocol.
Windows 95, 98 and NT contain software that assigns IP addresses to workstations
on a network. These assignments are made by the DHCP server software that
runs on Windows NT Server, and Windows 95 and 98 will call the server
to obtain the address. Windows 98 will allocate itself an address if no
DHCP server can be found.
See also IP address, server.
distributed
intelligence
A networking scenario by which processing power is distributed
among several attached devices working independently while continuing
to provide functionality as part of the larger system.
See also client/server.
De-Militarized Zone. A part of a network that is accessible externally, but remains protected from hacker attacks. The OfficeConnect Internet Firewall DMZ features a de-militarized port that is used for connecting publicly accessible servers such as a web server. The DMZ port is protected from DoS hacker attacks, but can be accessed by external Internet users. A DMZ port enables users to access your Web site without exposing the rest of your network to attack.
See also DoS, firewall, hacker, Internet, network, OfficeConnect, port.
DNS
Domain Naming System. DNS translates
a common alphabetic name into its numeric IP address. A DNS server lets
users locate computers on the Internet by maintaining a database of host
names and IP addresses.
See also domain name,
Internet,
IP
address.
domain
name
The address of a network connection (for example www.3com.com)
that identifies the hierarchical owner of the address.
See also DNS.
Denial of Service. A specific type of hacker attack where the intention is simply to make your network unusable for users. An example of this is "mail-bombing", where someone tries to flood your e-mail server with so many e-mails that legitimate users can no longer use the system. Adding a firewall to your LAN can prevent this.
See also e-mail,
firewall, hacker, LAN,
network, server.
DOS
Disk Operating System. A computer
operating system developed by Microsoft and IBM: IBM PCs use PC-DOS, and
non-IBM PCs use MS-DOS. Microsoft's Windows 95 and Windows NT are newer
computer operating systems than DOS.
See also PC.
driver
Software that controls a port such as a network interface
card (NIC), keyboard, printer or monitor. Network equipment (such as hubs)
attached to PCs requires drivers that the PC uses to communicate with
them.
See also NIC,
PC,
port.
DSL
Digital Subscriber Line. A technology for bringing
high-bandwidth information to homes and small businesses over ordinary
copper telephone lines.
See also bandwidth.
Dual
Speed Hub
The OfficeConnect Dual Speed Hub 8 and Dual Speed Hub 16 are easy-to-use
hubs with 8 or 16, 10/100BASE-TX ports. Each port can be connected to
either an Ethernet or a Fast Ethernet device. Each port automatically
senses the speed of the connected device and operates at the highest speed
possible.
See also 10/100,
Ethernet,
Fast Ethernet,
OfficeConnect.
duplex
Transmission that permits simultaneous two-way communication.
Duplex is synonymous with full duplex.
See also full duplex,
half
duplex.
duplex cable
Cable that contains both a transmit (Tx) and receive (Rx)
channel.
See also full duplex,
half duplex.
e-mail
EIA
EIA/TIA-232
EMC
encryption
Ethernet
e-mail
Electronic mail. This is the transmission
of messages to individuals or groups, over a network. E-mails may contain
text messages, tables, charts and pictures as well as attachments. The
use of e-mail in an office environment can reduce the need for paper,
as memos and inter-office communication can be sent over the network,
thereby saving time and valuable resources.
See also network.
EIA
Electronic Industries Association.
An industry trade organization that, together with the TIA (Telecommunications
Industry Association), sets standards for electrical consumer products.
The EIA and TIA specify data transmission standards such as EIA/TIA-232.
See also EIA/TIA-232,
TIA.
EIA/TIA-232
The EIA/TIA-232 is a standard for a 25-pin serial interface
that can be used to connect computers to networking equipment. (EIA/TIA-232
was formerly known as RS-232.)
See also EIA, network,
TIA.
EMC
Electromagnetic compatibility. The
ability of a device to operate effectively in the environment in which
it was intended, without receiving electromagnetic interference (EMI)
from other devices and equipment, or generating it.
encryption
Encryption is the process of encoding data during transmission to prevent
unauthorized access.
Ethernet
Ethernet was invented by Xerox Corporation and developed jointly by Xerox,
Intel, and Digital Equipment Corporation (DEC) and is a widely used LAN
technology.
Ethernet networks use the CSMA/CD protocol and run over various cables
at a rate of 10Mbps; they are used by, for example, TCP/IP and XNS protocols.
Ethernet is similar to a series of standards produced by IEEE referred
to as IEEE 802.3.
See also CSMA/CD, Fast
Ethernet,
IEEE,
LAN,
Mbps,
protocol,
TCP/IP,
XNS.
Fast
Ethernet
FCC
FDDI
fiber-optic cable
filter
filtering
firewall
frame
frame relay
full duplex
Fast Ethernet
Fast Ethernet operates at 100Mbps and so has 10 times more
bandwidth than Ethernet, enabling it to cope with larger amounts of traffic;
this results in operation 10 times faster than Ethernet. Fast Ethernet
runs over the various 100BASE (cables): for example, 100BASE-FX and 100BASE-TX.
Fast Ethernet networks operate at 100Mbps and are based on the 10BASE-T
Ethernet CSMA/CD network access method, an extension to the IEEE 802.3
specification.
See also 10BASE-T,
100BASE-FX,
100BASE-TX,
bandwidth,
CSMA/CD,
Ethernet,
IEEE, Mbps,
network, traffic.
FCC
Federal Communications Commission. The regulatory
telecommunications body for the U.S.A. that licenses and controls electronic
and electromagnetic transmission standards. The FCC specifies bandwidth
ranges for different communication channels.
FDDI
Fiber Distributed Data Interface. This is
a network standard for high speed transmission over fiber-optic cable.
FDDI uses two rings of fiber-optic cabling (providing greater resilience)
and transmits at 100Mbps at distances up to 2km (1.24 mile) between nodes.
FDDI is typically used as a backbone technology providing connectivity
between Ethernet and Token Ring networks. It is used in critical applications,
for example in an airport.
See also backbone,
Ethernet,
fiber-optic cable,
LAN, Mbps,
node, packet,
protocol,
server,
Token Ring.
fiber-optic cable
A cable containing one or more optical fibers used for
transmitting data in the form of light. Fiber-optic cable is more expensive
than copper but is not susceptible to electromagnetic interference and
is capable of higher data transfer speeds over greater distances.
A pattern or mask through which only selected data is passed. For example, certain e-mail systems can be programmed to filter out important messages and alert the user. Web site filtering is a function of firewalls and allows the user to control Internet access from her/his site. The user specifies the categories of material and the web site filter provides a list of thousands of controlled sites. Access can either be blocked or logged.
See also
e-mail, firewall, Internet.
filtering
A process where network traffic is screened for certain
characteristics, such as destination address (the address of the device
for which the packet is intended) or protocol. From this process it is
determined whether traffic is forwarded based on the established criteria.
This allows only essential internetwork traffic to cross a bridge thereby
reducing internetwork traffic.
Filtering in routers can prevent unauthorized access to a network or host
on a network; this barrier is often called a firewall. Filtering
is performed by bridges, switches and routers.
See also bridge, internetwork,
network, packet,
protocol, router,
switch, traffic.
firewall
A firewall in a network is a node set up as a barrier to
prevent traffic crossing from one segment to another. Firewalls are used
to improve network traffic as well as for security purposes, and may serve
as a barrier between connected public and private networks. A firewall
may be implemented in a router or it may be a network device specialized
for this purpose.
See also network,
node,
router,
segment,
traffic.
frame
A frame is a set of bits that form a basic block of data.
Usually, a frame contains its own control information, including the address
of the device to which it is being sent.
From a piece of networking equipment, frames can be unicast (sent to a
single device), multicast (sent to multiple devices) or broadcast (sent
to all devices).
See also broadcast,
multicast, packet,
unicast.
frame
relay
Frame relay is a high-speed packet switching protocol used
in WANs. It is popular for LAN to LAN connections across remote distances
and is suitable for data and image transfer. Due to its variable-length
packet architecture it is not the most efficient technology for voice
and video. Frame relay is more popular in the U.S. than it is in Europe.
See also Asynchronous Transfer Mode, LAN, network, packet, WAN.
full
duplex
The ability of a device or line to transmit data simultaneously
in both directions over the same communications link, potentially doubling
the throughput of traffic.
See also bandwidth,
duplex cable,
half duplex.
gateway
Gigabit Ethernet
Graphical User Interface
gateway
A device that interconnects networks with different, incompatible
communications protocols. The gateway performs a protocol conversion to
translate one set of protocols to another (for example, from TCP/IP to
IPX).
See also network,
IPX,
OfficeConnect,
OSI reference model,
protocol,
TCP/IP.
Gigabit
Ethernet
Gigabit Ethernet is an extension to 10 Mbps (Ethernet)
and 100 Mbps (Fast Ethernet) IEEE 802.3 Ethernet standards. Gigabit Ethernet
operates at a speed of 1000 Mbps and maintains full compatibility with
the installed base of Ethernet nodes.
See also Ethernet,
Fast Ethernet,
Mbps,
network, node.
Graphical
User Interface (GUI)
A visual computing interface which represents commands,
files and other computing actions with icons, symbols and dialog boxes.
A GUI could be a web interface.
hacker
half duplex
HTML
hub
hypertext
HyperText Markup Language
A person who writes programmes in assembly language or in a system-level language, such as C. Although it may refer to any programmer, it implies "hacking away" at the bits and bytes. More recently the term has become widely used for people who try to gain unauthorised access to a computer system by any means.
half duplex
The term half duplex is used to describe data transmission
that can occur in two directions over the same communications link, in
only one direction at a time. Hubs only operate in half duplex mode, as
opposed to switches which can operate in both full duplex and half duplex.
See also duplex cable,
full duplex, hub,
switch.
See also Hypertext
Markup Language.
hub
A hub serves as a central location for connecting computers
and other devices (such as printers) together. A hub is sometimes referred
to as a multiport repeater because it passes on, or repeats, all the packets
it receives to all its ports.
See also OfficeConnect,
packet,
repeater,
switch.
hypertext
A word or phrase in an online document that is linked to
another section of the same document or to a different document. Hypertext
words and phrases are usually in blue and underlined.
HyperText
Markup Language (HTML)
A language used to create pages for the World Wide Web.
See also WWW.
IEEE
IGMP
Internet
Internet
Engineering Task Force
Internet
Group Management Protocol
internetwork
intranet
IP
IP address
IPX
ISA
ISDN
ISP
ITU
IEEE
Institute of Electrical and Electronics
Engineers. This organization was founded in 1963 and sets standards
for computers and communications. The committee that formed the 802 standards
for networking was set up in 1980 to ensure that systems and devices manufactured
by different vendors could communicate with the minimum of complications,
allowing global compatibility across products.
See also Internet Group Management Protocol.
Internet
The Internet is a worldwide network composed of government,
academic, commercial, military and corporate networks spanning the world.
The Internet was originally developed for the U.S. military and then became
widely used for academic and commercial research. Users accessing the
Internet can read and download data on virtually any subject from almost
anywhere in the world.
See also intranet,
network,
WWW.
Internet Engineering Task
Force (IETF)
A committee that reviews and supports Internet protocol
proposals.
See also protocol.
Internet
Group Management Protocol (IGMP)
A protocol used by Internet hosts to report their multicast
group memberships to any immediately neighboring multicast routers. It
is required to be implemented by all hosts wishing to receive IP multicasts.
IGMP messages are encapsulated in IP datagrams. Multicast protocols are
important when you are trying to reduce or limit broadcast traffic on
network. Multicast protocols also come into play if someone is trying
to run broadcast video training over the network to specific students
distributed across a multi-segment network. Instead of the video stream
being broadcast to everyone, the video stream is only addressed to particular
PCs.
See also broadcast,
datagram,
Internet,
IP,
multicast,
network,
protocol,
router, segment,
traffic.
internetwork
A collection of networks (that may be dissimilar in type)
interconnected by routers, gateways, or other devices, so that they can
function as a single, large network. Sometimes called an internet, which
is not the same as the Internet (the World Wide Web).
See also Internet,
network,
router,
WWW.
intranet
Intranets are internal, private networks used by companies
and academic institutions worldwide. Intranets are secure from public
access and serve as databases of information in the same format as that
used by the World Wide Web.
See also internet,
network,
World Wide Web.
IP
Internet Protocol. IP is a layer 3 network
protocol (of the OSI reference model) that is the standard for sending
a basic unit of data (an IP datagram) through an internetwork. IP is part
of the TCP/IP set of protocols describing the routing of packets to addressed
devices.
See also datagram,
Internet,
internetwork,
packet,
protocol,
OSI reference model,
TCP/IP.
IP address
The Internet Protocol address is the network layer address of a device
assigned by the user or network administrator of an IP network. An IP
address consists of 32 bits divided into two or three fields: a network
number and a host number or a network number, a subnet number, and a host
number.
See also bit,
IP, network.
IPX
Internet Packet Exchange. A communications protocol
devised by Novell for Novell NetWare. IPX packets can be routed from one
network to another at layers 3 and 4 of the OSI reference model.
See also Internet,
network,
OSI reference model,
packet.
ISA
ISA sockets are about
14cm long and are Industry Standard Architecture
sockets have been standard since the first PC They are still used in modern
PCs because of the huge range of expansion cards designed for them. 3Com
ISA cards support 10Mbps performance only.
ISDN
Integrated Services Digital Network.
An international telecommunications standard for transmitting voice, video,
and data over digital lines running at 64Kbps. ISDN is used for private
or public digital telephone networks where binary data, such as graphics
and digitized voice and data transmission, pass over the same digital
network that carries most telephone transmissions today.
See also Kbps,
network,
OfficeConnect.
ISP
Internet Service Provider. A business
that provides Internet access to individuals or organizations.
See also Internet.
ITU
International Telecommunications Union.
The organization within which governments and the private sector coordinate
global telecom networks and interfaces.
Kbps
Kbps
Kilobits per second. The measurement
of the speed of data transfer in a communications system. One kilobit
is equal to 1000 bits.
See also bit,
Mbps.
LAN
LAN Modem
LANtastic®
Layer 1
leased lines
LED
link
loop
LAN
Local Area Network. A network of connected
devices (such as PCs, printers, servers and hubs) covering a relatively
small geographic area (usually not larger than a floor or building). LANs
are characterized by high transmission speeds over short distances. Ethernet,
FDDI and Token Ring are widely used technologies for configuring LANs.
See also Ethernet,
Fast Ethernet,
FDDI,
hub,
network,
server,
Token Ring.
LAN Modem
A LAN Modem is an ISDN or analog router with a built-in
Ethernet hub, allowing several workstations to share a single connection
to an ISP or remote office LAN, while transferring files locally among
all attached workstations.
See also
Ethernet, hub,
ISDN,
ISP,
LAN,
router.
LANtastic
This is a peer-to-peer operating system developed by the
company Artisoft for Ethernet and Token Ring networks.
See also Ethernet,
network, peer-to-peer
networks,
Token Ring.
Layer 1
In ISDN communications, this is the physical 'layer' of
communication between the communications equipment, according to the OSI
reference model. If layer one is down, there is no ISDN connection between
the devices.
See also ISDN, OSI reference
model.
leased
lines
A connectionless network where the user is charged a flat fee instead
of connection charges and per minute charges typically associated with
long distance calls.
LED
Light Emitting Diode. A semi-conducting
light source that emits light by converting electrical energy. LEDs on
3Com OfficeConnect products provide status information on the device and
the network to which it is attached.
See also network,
OfficeConnect.
link
Physical connection between two nodes in a network.
See also network, node.
loop
See also network
loop.
Mac
MAC
MAC address
MAC encapsulation
mainframe computer
managed device
Mbps
MBps
MDI
MDI/MDI-X
modem
multicast
Multilink PPP
Multiplexer
Mac
The abbreviation for Macintosh computer.
MAC
Media Access Control. A protocol for
determining which devices have access to a network at any one time, specified
by the IEEE. The MAC protocol differs depending on the method used to
connect the network (for example Token Ring or Ethernet).
See also Ethernet,
IEEE,
MAC address,
network,
protocol,
Token Ring.
MAC address
Media Access Control address; also
called hardware address or physical address. An address associated with
a particular network device. NICs and managed devices that connect to
a LAN have a MAC address assigned to them as MAC addresses are used to
identify devices in a network. MAC addresses are 6 bytes long, are specified
by the IEEE and are preassigned to your network equipment.
See also byte,
IEEE,
LAN,
MAC,
managed device,
network,
NIC.
A method for Media Access Control IP packet construction where the entire frame from one network is simply enclosed, or encapsulated, in the header used by the link-layer protocol of the other network. MAC is a sub-layer of the OSI Reference Model data-link layer used to control access to a transmission medium.
See also Token Ring, CSMA/CD, Ethernet, and FDDI.
mainframe computer
A powerful central computer designed for high-level computing
tasks. Mainframe computers are often accessed by multiple users via attached
workstations.
managed device
Managed devices are those that support network management. A device in
the OfficeConnect range that is managed is the OfficeConnect Ethernet
Hub 8.
See also network
management,
OfficeConnect.
Mbps
Megabits per second (not to
be confused with megabytes per second —MBps). The measurement
of the speed of data transfer in a communications system. A megabit is
one million bits. Ten megabits per second (10Mbps) means that 10 million
pulses are transmitted per second in a communications system.
See also bit,
MBps.
MBps
MegaBytes per second (not to be confused with
megabits per second —Mbps). The measurement of the speed of
data transfer in a communications system. A megabyte is approximately
one million bytes. [1 MB = 1,048,576 bytes.]
See also byte,
Mbps.
MDI
Medium Dependent Interface. MDI refers to an Ethernet
port connection. The IEEE 802.3 network standard defines MDI as the electrical
and mechanical interface between a piece of equipment and a transmission
medium.
Within an RJ-45 port there is a transmit line and a receive line. RJ-45
ports can be MDI (the lines are uncrossed) or MDI-X (the lines are crossed).
For a connection between two devices to work, the receiver of one device
must be connected to the transmitter of the other, therefore, the MDI
port of one device must be connected to an MDI-X port of another device
using straight-through cable. MDI is also known as Uplink, and MDI-X is
known as Normal.
See also Ethernet,
IEEE,
MDI/MDIX,
network,
OfficeConnect,
port,
RJ-45,
straight-through
cable,
Uplink/Normal.
MDI/MDI-X
Medium Dependent Interface/Medium
Dependent Interface crossover. The switch, also known as
Uplink/Normal, located on the back of an OfficeConnect switch or hub that
is used to alter the operation of a specific port. The 'X' stands for
crossing the transmit and receive lines of a port. An MDI port (Uplink,
uncrossed) connects to the MDI-X (Normal, crossed) port of another hub.
See also hub,
OfficeConnect,
MDI,
port,
switch.
modem
MOdulator-DEModulator. A device that adapts
a computer's digital signal into audio frequencies (analog) for transmission
down a telephone line, and adapts them back again. Transmission speeds
of modems generally range from 2,400bps (2.4Kbps) to 56,000bps (56Kbps).
See also bps,
Kbps.
multicast
A message sent simultaneously to a specific group of nodes on a network.
See also broadcast,
network,
node.
Multilink PPP
Multilink Point-to-Point Protocol.
Multilink PPP is a protocol that provides a method for combining multiple
PPP connections. Multilink PPP aggregates the two 56 Kbps or 64 Kbps ISDN
B channels, creating a virtual single digital connection of 112 Kbps or
128 Kbps.
See also B channel,
ISDN,
Kbps,
PPP,
protocol.
multiplexer
A device used in communication lines for funneling separate
data signals simultaneously across a single channel.
NAT
NDIS
NetBEUI
NetBIOS
NetWare
network
Network Driver
Interface Specification
network loop
network management
Network Ready
Network Terminator (NT-1)
network utilization
NIC
node
NOS
NT-1
NAT
Network Address Translation. The process whereby multiple LAN users can
share a single IP address from an ISP. This means multiple users can access
the internet using an Ethernet modem and an Internet account.
See also Ethernet,
Internet, IP
address, ISP, LAN, modem,
network.
See also Network Driver Interface Specification.
NetBEUI
NetBIOS Extended User Interface.
This is an enhanced version of the NetBIOS protocol used by network operating
systems (NOS), such as Microsoft's Windows NT. NetBEUI is pronounced "netbooey".
See also frame,
LAN,
NetBIOS,
network,
NOS, protocol.
NetBIOS
Network Basic Input/Output
System. A common network protocol for local area networks (LANs)
that contain PCs (personal computers).
NetBIOS is an established network standard that provides the interface
between a PC's operating system and its input/output channel. NetBIOS
was later formalized in NetBEUI.
See also frame,
LAN,
NetBEUI,
network,
NOS,
OSI reference model,
PC,
protocol.
NetWare
A network operating system (NOS) developed by Novell. NetWare
supports DOS, Mac and UNIX, plus various LAN network technologies such
as Ethernet and Token Ring. For a more detailed description of network
operating systems, refer to NOS.
See also Ethernet,
LAN,
Mac,
network,
NOS,
Token Ring,
UNIX.
network
A group of devices such as computers, printers, hubs, switches, and other
hardware, that are connected and are able to communicate with each other.
Networks vary in size: some are within a single office, others span the
globe.
See also hub,
internetwork,
switch.
Network Driver Interface
Specification (NDIS)
A software specification
used in some network operating systems (such as LAN Manager and Windows
NT) to create drivers for network adapters. NDIS drivers support multiple
protocols and multiple adapters.
See also driver,
NOS,
protocol.
network loop
This occurs when two pieces of network equipment are connected
by more than one path, thereby causing packets to repeatedly cycle round
and round the network and not reach their destination. A repeating hub
will detect network loops and automatically partition one of its ports
to break the loop.
See also hub,
network,
packet,
partition.
network management
As your network grows, it may be necessary to manage
communications on your network. This is called network management. Monitoring
a network allows you to diagnose problems and gather statistics on network
performance, for administration purposes.
See also hub,
managed device,
network,
OfficeConnect,
switch.
Network Ready
A 3Com trademarked name for PCs that are built with pre-installed
drivers and a 3Com network interface card (NIC). Every PC with a 3Com
Network Ready logo is certified to be functional in virtually every network
operating system environment.
See also driver,
network,
NIC,
NOS,
PC.
Network Terminator (NT-1)
An NT-1 is a network device that terminates the ISDN line.
An NT-1 is built into the U version of the OfficeConnect ISDN LAN Modem,
for use in North America and other countries that do not require an external
NT-1. The ISDN LAN Modem with the S/T interface is for use in Europe and
other countries that do require the use of an external NT-1.
See also ISDN,
LAN Modem.
network
utilization
The amount of traffic present on a network as a percentage
of the network's bandwidth. Utilization indicates how much of the network's
capacity is being used.
See also bandwidth,
network.
NIC
Network Interface Card. (Also known
as an adapter or adapter card.) A circuit board installed
into a piece of computing equipment, for example, a PC, that enables you
to connect your PC to the network.
See also network,
OfficeConnect,
PC.
node
A communication device attached to a network, such as a computer or server.
See also network,
server.
NOS
Network Operating System. A network
operating system is software that allows users to share files, printers,
faxes, modems and to access a server.
Network operating systems manage network resources that can be completely
self-contained (such as NetWare) or require an existing operating system
in order to function (LAN Manager requires OS/2, and LANtastic requires
DOS). Examples of network operating systems are Windows NT, Windows for
Workgroups, Windows 95, Windows 98 and LANtastic.
See also DOS,
LAN,
LANtastic,
modem,
NetWare®,
network,
server.
NT-1
An NT-1 is a network
device that terminates the ISDN line. An NT-1 is built into the U version
of the OfficeConnect ISDN LAN Modem, for use in North America and other
countries that do not require an external NT-1. The ISDN LAN Modem with
the S/T interface is for use in Europe and other countries that do require
the use of an external NT-1.
See also ISDN,
LAN Modem.
OfficeConnect
OSI
OSI reference model
OSPF
OfficeConnect
The OfficeConnect family of products provide small businesses
with the power to share information, connect remote locations and access
the Internet. Delivering the powerful advantages of networking to small
businesses, installation of the market-leading OfficeConnect system can
streamline your business, effectively manage costly resources, and increase
communication.
The broad range of products within the OfficeConnect range—from hubs and networking kits to print servers, switches and routers—-are designed from the ground up to meet the needs of small businesses and provide simple, reliable, and affordable solutions for today's information sharing needs.
See also hub,
modem, NIC,
router, switch.
OSI
Open System Interconnection. International computer
network standards developed by ISO and CCITT (Consultative Committee for
International Telephony and Telegraphy) to create common standards of
communication between computers from different manufacturers.
See also network,
OSI reference model.
OSI reference
model
Open Systems Interconnection reference
model. The OSI reference model is a worldwide industry standard used in
computer networking to define how protocols communicate over a network.
The OSI reference model was designed to help developers create applications
that are compatible across multivendor products.
Learning the OSI layers and functions helps to understand communications networks.
Briefly, when one device in a network want to communicate with another by sending a message (for example, an e-mail), the message passes "down" through the layers of the model. Each of the seven layers attaches instructions to the message, until the complete package is in a suitable form to be passed across the network. The message is deciphered by the model as the message passes back up through the layers reaching its destination at the end.
See also Ethernet, Fast Ethernet, hub, Internet, network, router, switch.
OSPF
Open Shortest Path First. A
network routing protocol used on IP networks such as the Internet, which
locates the shortest path to each node on the network.
See also Internet,
IP,
network.
packet
PAP
partition
PC
PC card
PCI
PCMCIA
peer-to-peer network
PING
POP
port
POTS
power adapter
PPP
PPTP
PRI
print server
protocol
Public Switched Telephone
Network
packet
A packet is unit of information that your workstations
and other equipment send to each other over the network. When information
is sent from a computer (for example a text file), it is transmitted over
the network as a series of packets.
A packet consists of a set of bits forming a single block of data, containing
a header which consists of control information such as sender, receiver,
and error-control data, as well as the message itself. Because they are
similar units of network data, the terms packet and frame
have become interchangeable.
See also bit,
frame,
hub,
network,
router,
switch.
PAP
Password Authentication Protocol.
PAP is the protocol that verifies a username and password for PPP connections.
This protocol is used if the more extensive CHAP is not available.
See also CHAP,
PPP,
protocol.
partition
A partition in a network is when one or more ports are
isolated, for example, to remove a network loop. 3Com OfficeConnect devices
detect network loops and partition their ports to remove the loops.
See also hub,
network,
network loop,
OfficeConnect,
port, switch.
PC
Personal Computer. Although PC is now the
term generally used for any personal computer, the original PC standard
was developed by IBM.
PC
card
The PCMCIA created a 16-bit socket into which credit card-sized
cards are plugged: these are commonly known as PC cards. The ports on
these cards attach, for example, modems, sound cards and hard disks to
portable computers.
See also modem,
NIC,
port,
PCMCIA.
PCI
Peripheral Component Interconnect
sockets are used in all Pentium desktop PCs. PCI sockets provide a much
higher performance than ISA, this is essential to get the most out of
modern high performance expansion cards. PCI sockets are about 9cm long.
3Com PCI cards support either 10Mbps or 10/100Mbps networking.
See also Ethernet,
Fast Ethernet,
ISA,
NIC,
Mbps,
PC.
PCMCIA
Personal Computer Memory Card
International Association. This non-profit making organization
was set up in 1989 to standardize a method for connecting equipment to
portable computers.
See also PC card.
peer-to-peer
network
A peer-to-peer network is one in which workstations (such
as PCs) can share information and each other's resources without relying
on a centralized server. For example, in a network of four PCs and one
hub, it is possible to allow files on all four PCs to be accessed from
any other PC.
See also
client/server
network, hub,
network,
PC,
server.
PING
Packet INternet Groper. A test of
the path between the managed device and another device on an IP network
that responds to IP (Internet Protocol) packets. During a ping test, the
managed device sends ICMP (Internet Control Message Protocol) echo request
packets to another node with the specified IP address and waits for echo
response packets to return. The node must be capable of receiving and
responding to ICMP packets.
See also IP,
packet,
protocol.
POP
Point of Presence. The point in a
WAN that connects local telephone calls to the network.
See also WAN.
port
A socket from where data can enter and leave a computer,
or a networking device. On a personal computer, the serial (console) and
parallel ports are for plugging in communications lines to equipment such
as modems, routers and printers.
See also internetwork,
modem,
router.
POTS
Plain Old Telephone Service.
POTS refers to a basic telephone connection to the public switched network.
power adapter
A power adapter is a transformer that converts the alternating
current (AC) from a wall outlet, into direct current (DC) required by
an electronic device.
PPP
Point-to-Point Protocol. PPP provides
a standard method of establishing a dial-up connection to the Internet.
PPP is used for communication between a computer and an ISP.
See also Internet,
ISP,
Multilink PPP.
PPTP
Point-to-Point Tunneling Protocol. A protocol
that allows a workstation to establish a secure multi-protocol connection
to a remote, private network via a locally dialed ISP account.
See also ISP,
protocol,
VPN.
PRI
Primary Rate Interface. A PRI line
is one of two access methods to ISDN; BRI is the other. In North America
PRI consists of twenty-three 64 Kbps B channels and one 64 Kbps D channel
(known as 23B+D). The European PRI consists of 30 Kbps B channels and
one 64 Kbps D channel (known as 30B+D).
See also B channel,
BRI,
D channel,
Kbps,
ISDN.
print
server
Print servers permit a printer to be located anywhere on
a network. They act as the "server" receiving information and
passing it on to the printer so that jobs can be printed.
protocol
In networking, a protocol is a formal set of rules and
conventions developed by international standards bodies that govern how
devices on a network exchange data. A protocol defines format, timing,
control and sequence of data in a network.
See also network.
Public
Switched Telephone Network (PSTN)
The telephone network ubiquitous over the world. Its components are telephones,
RJ-11 twisted-pair cabling, and the central office. PSTN is also called
POTS (plain old telephone service). The main reason PSTN has not be replaced
with a newer technology such as ISDN is that PSTN works when electrical
power is out. ISDN requires a separate power supply.
See also ISDN,
POTS,
RJ-11,
twisted pair (TP).
RAS
repeater
RJ-11
RJ-45
roaming
router
Routing Information Protocol
RS-232
RAS
Remote Access Server. The device on
a network made up of a bank of modems that allows users to connect to
the network over dial-up telephone lines.
See also modem,
server.
repeater
A repeater is a simple device that regenerates a signal
passing through the network, so that the transmission distance of that
signal can be extended. A multi-port repeater is known as a hub.
The further a data packet travels along a network, the weaker the signal
carrying that data packet becomes. Repeaters repeat (regenerate)
data packets they so that neither the number of packets that pass through
them, nor the distance they travel, has any effect on signal quality.
Repeaters are also used to connect two LANs of the same network type (for
example Ethernet to Ethernet) and work at layer 1 of the OSI reference
model.
See also bridge, hub,
LAN,
Layer 1,
network,
OSI reference model.
RJ-11
A standard connector used to connect analog devices to
a telephone line. The "RJ" stands for "registered jack".
RJ-45
A standard connector used to connect Ethernet networks.
The "RJ" stands for "registered jack".
The ability to move from point to point on a wireless network without losing connectivity.
router
Routers provide a link between geographically separate
networks. An internetwork based on routing consists of many different
logical subnetworks. Bridges and switches connect these subnetworks, improving
network performance by keeping traffic within segments. Repeaters and
hubs link segments together, and the workstations within the segments.
See also bridge,
hub,
network,
segment,
switch,
traffic.
Routing Information Protocol
(RIP)
The process of moving a packet from one node to another by forwarding
the packet to the next router.
RS-232
See also EIA/TIA-232.
security
segment
Serial Line Internet
Protocol
server
SLIP
SNMP
SPID
Spoofing
SPX
Stateful Packet Inspection
STP
straight-through
cable
subnet address
subnet mask
subnets
switch
Symmetric
transmission
In networking terms security is the protection of data and system resources against unauthorised access. Programmes and data can be secured by issuing identification codes and passwords to authorised users of a computer. However, systems administrators or other suitably authorised individuals will ultimately have access to these codes, so there is always the risk that this information may fall into the wrong hands.
Passwords can be checked by the operating system to prevent users from logging onto the system in the first place, or they can be checked in software. Any application programme running in the computer can also be designed to prevent eavesdropping. Although precautions can be taken to detect an unauthorised user, it is extremely difficult to determine if a valid user is performing unauthorised tasks. Effective security measures are a balance of technology and personnel/process management.
segment
A group of devices such as PCs, servers or printers that
are connected by network equipment. On Ethernet segments, computers can
be connected together by hubs, and signals broadcast on that segment are
heard by all stations attached to it. If the segment is interconnected
to another segment with a bridge or router, it is possible to send packets
between those segments. Network segments joined with bridges or routers
form internetworks. A segment is often called a subnetwork.
See also bridge,
Ethernet,
hubs,
internetwork,
network,
packet,
PC,
router,
server.
Serial
Line Internet Protocol (SLIP)
SLIP is a de facto standard, commonly used for point-to-point
serial connections running TCP/IP.
See also PPP,
protocol,
TCP/IP.
server
A computer or specialized device in a network that is shared
by multiple users. A server provides users with access to shared network
services such as computer files and printers.
See also client/server,
network.
See Serial
Line Internet Protocol.
SNMP
Simple Network Management Protocol.
An IETF defined standard protocol for the exchange of management information
between entities on the Internet. SNMP is now the de facto standard for
virtually all LAN management. It defines the format for the management
data and the type of exchanges that may take place between a management
station and the device to be managed on the network.
See also protocol,
TCP/IP.
SPID
Service Profile IDentifier. If required,
this number is supplied to you by the telephone company. Typically, if
your ISDN line has only one telephone number, or you are not using ISDN
service in North America, a SPID is not required.
See also ISDN.
spoofing
This reduces network overload by reducing traffic on a
WAN (such as signals that repeatedly state a device is alive). The router
or bridge can tell a remote device that a LAN device is still powered
on instead of the LAN device informing the remote device it is still powered
on.
See also bridge,
LAN,
router,
traffic,
WAN.
SPX
Sequenced Packet Exchange. A communications
protocol developed by Novell for use with NetWare used to control the
transport of messages across a network.
See also NOS,
protocol.
A filtering method used by firewalls in which all aspects of the data going in and out of a network are inspected for destination, source and data type.
See also firewall,
network.
STP
Shielded Twisted Pair. Cabling consisting of one
or more pairs of insulated wires used in a variety of network applications.
The wires are wrapped in metal to eliminate electromagnetic interference
(EMI) and are of a better quality than UTP (Unshielded Twisted Pair).
See also Category
3 cabling,
Category 5 cabling,
network,
twisted pair,
UTP.
straight-through
cable
A straight-through cable has its wires connected to the
same pins at both ends (including the transmit and receive wires). For
a connection between two devices to work, the receiver of one device must
be connected to the transmitter of the other. Therefore, when connecting
an Normal (MDI-X) port to an Uplink (MDI) port, a straight-through cable
must be used. Straight-through cable is the most common type of off-the-shelf
cable available for networking.
See also MDI/MID-X,
port,
Uplink/Normal.
subnet
address
An extension of the IP addressing scheme that allows a
site to use a single IP network address for multiple physical networks.
See also IP,
network.
subnet
mask
A subnet mask is a term used to indicate how much of an
IP address is used to identify the network. An IP address has two parts,
the first identifies the network and the second identifies the machine
or PC on the network.
See also IP address,
network.
A network that is
a component of a larger network.
switch
A switch only forwards information as necessary (unlike
a hub, which forwards information to all its ports). Once it has learned
which devices can be reached through each port, a switch passes on packets
only to the appropriate ports. In this way, a switch can dramatically
reduce the amount of traffic and improve the performance of a network.
A switch, such as an OfficeConnect Switch, is typically used to connect
hubs together, or to provide dedicated connections to high performance
workstations.
See also hub,
OfficeConnect, packet.
A technology permitting large data transfers to occur at high bandwidth both toward and away from the user.
TCP/IP
terminal adapter
thick coax
thin coax
TIA
Token Ring
traffic
transceiver
twisted pair
TCP/IP
Transmission Control Protocol/Internet
Protocol. This is the name for two of the most well-known protocols
developed by the U.S. Department of Defense in the 1970s to allow equipment
from different vendors to communicate. Originally a UNIX standard, TCP/IP
is now supported on almost all platforms, and is the protocol of the Internet.
IP represents the scheme by which two devices (both with IP addresses)
communicate. TCP manages the flow of IP packets, ensuring that the packets
remain error-free and reach their destination correctly.
See also Internet,
internetwork,
IP,
network,
nodes,
packet,
protocol,
UNIX.
terminal adapter
A device used in an ISDN network to connect a single user
to the outside world.
See also ISDN.
thick coax
See also 10BASE5.
thin coax
See also 10BASE2.
TIA
Telecommunications Industry Association. A telecommunications
standards organization founded in 1988 in America. The TIA was formed
from a spin-off group from the EIA (Electronic Industries Association)
to set global telecommunications standards, such as EIA/TIA-232.
See also EIA,
EIA/TIA-232.
Token Ring
Developed by IBM, Token Ring offers a method to connect
devices in a LAN (local area network). Hence, Token Ring offers the same
service as Ethernet, implemented in a different manner: an electronic
token (a data packet) is passed around stations in a ring. Most small
businesses install Ethernet networks, due to their comparative simplicity
to Token Ring.
Token Ring networks take on the physical appearance of a star, but actually
operate as a logical ring. A device (such as a PC) takes possession of
the token, transmits its data, then frees the token after the data has
made a complete circuit of the electrical ring.
The IEEE 802.5 standard specifies the wiring on which Token Ring operates
(STP, UTP or fiber-optic cable); Token Ring operates at either 4 or 16Mbps.
See also Ethernet,
fiber-optic cable,
IEEE,
LAN,
Mbps,
network,
packet,
PC,
STP,
UTP.
traffic
Movement of data packets on a network.
See also network,
packet.
transceiver
A device that transmits and receives digital and analog
signals. In networking, a transceiver is a device that connects an interface
to a local area network (LAN). Transceivers can be standalone units, or
incorporated into a circuit board within a computer. They are usually
used to connect media of different types, for example, thick coaxial cable
to an AUI.
See also 10BASE5,
AUI,
coaxial cable, collision,
Ethernet,
LAN,
network,
traffic.
twisted pair (TP)
A pair of thin wires commonly used for telephone wiring
and computer networks. The wires are twisted around each other to minimize
interference from other cables.
The two major types of twisted pair are shielded twisted pair (STP) and
unshielded twisted pair (UTP). UTP is popular because it is thinner and
doesn't take up much room, but STP has added protection against electromagnetic
interference.
See also bandwidth,Category
3 cabling,
Category 5 cabling,
coaxial cable,
fibre-optic cable,
network,
STP,
UTP.
unicast
UNIX
unmanaged device
Uplink/Normal
USB
USB Hub
USB
Network Interface
UTP
unicast
A message sent to an individual node on a network.
See also broadcast,
multicast, network,
node.
UNIX
An operating system developed at Bell Laboratories in 1969.
UNIX is an operating system which can run on a wide variety of hardware.
unmanaged device
Unmanaged devices are those that do not support network management.
See also network
management,
OfficeConnect.
Uplink/Normal
The switch located on the back of an OfficeConnect switch or hub that
is used to alter the operation of a specific port. An Uplink port (uncrossed)
connects to the Normal (crossed) port of another hub.
An example of using the Uplink/Normal switch is given below. The diagram shows three OfficeConnect hubs connected by 10BASE-T cable to form a stack.
- Starting from the bottom, connect the highest numbered port of the lower hub in the stack to any port of the hub immediately above. Repeat this for each hub.
- Set all Uplink/Normal switches to Uplink (in) except for the top hub (the one with the highest numbered port not connected to another hub). This unused port can be connected to a PC provided that the Uplink/Normal switch is set to Normal (out).
If you are using the highest-number port on your OfficeConnect hub to connect to a PC, ensure that the Uplink/Normal switch is set to Normal (out).
See
also hub,
MDI,
MDI/MDIX,
OfficeConnect,
port,
straight-through
cable,
switch.
USB
Universal Serial Bus. USB is a new
type of connection device fitted to most PCs available today. It provides
a way of connecting peripherals such as a printer, mouse, or a digital
camera (or the 3Com USB Network Interface), to a host PC. Its main benefits
are:
- It reduces the
need to install cards into dedicated computer slots and reconfigure
the system.
- It offers true plug and play set-up and hot swapping capability so devices can be added, removed or swapped while your PC is up and running.
USB ports now come as standard on the majority of desktop PCs. Check the
back of the PC, look for the official USB logo or contact the manufacturer
of your PC to confirm whether you have a USB port.
USB
Hub
Universal Serial Bus Hub. A USB Hub
provides a method of connecting multiple USB peripherals such as a printer,
mouse, or a digital camera (or the 3Com USB Network Interface), to one
PC. It cannot connect PCs together.
See also hub,
USB,
USB Network Interface.
USB
Network Interface
Universal Serial Bus Network Interface.
The 3Com USB Network Interface provides the link between a PC's USB port
and an Ethernet network. It performs the same function as a standard Network
Interface Card (NIC), without the need to open the PC to install the card.
Another key difference between the USB Network Interface and a conventional
NIC is the transmission speed. NICs are available in 10Mbps or 10/100Mbps
varieties, providing the highest speed connections between the PC and
the network. The USB Network Interface, because of speed limitations of
USB technology, is only available with a 10Mbps Ethernet connection.
See also Ethernet,
NIC,
Mbps,
USB.
UTP
Unshielded Twisted Pair. Cabling consisting
of one or more pairs of wires (used in a variety of network applications)
that are bound in plastic. UTP is popular because it is very pliable and
does not take up as much room as STP and other cables.
See also network,
STP,
twisted pair.
V.34
V.34+
V.90
V.everything
VPN
V.34
An ITU standard that currently allows data rates as high
as 28,000 bps.
See also bps,
ITU.
V.34+
An enhancement to V.34 that enables transfer rates as high
as 33,600 bps.
V.90
The ITU standard that allows modems to receive data at up to 56 Kbps over
the standard, public switched telephone network.
See also 56K,
ITU,
Kbps.
A term describing a modem which is compatible with another modem operating at the same speed.
See also V.34
VPN
Virtual Private Network. A virtual
private network is a secure, private data network that is established
over the Internet resulting in significant cost savings from using local,
toll free access numbers. Using the existing Internet backbone requires
less investment in private network infrastructure.
See also backbone, Internet, network, PPTP.
WAN
Web
WINS
wire speed
wireless client
wireless technology
Wizard
WLAN
WWW
WAN
Wide Area Network. A communications network that
covers a wide area. A WAN can cover a large geographic area, and may contain
several LANs within it. The true definition of a WAN is a network that
uses the main telephone network to connect its parts, but more generally
it is used to describe a network that spans a very large area.
See also LAN, network.
Web
See also WWW.
WINS
Windows
Internet Naming Service. A utility used to match a computer's host name
with its address.
wire
speed
Wire speed refers to the maximum capacity of a connection.
For Ethernet and Fast Ethernet connections this is normally defined by
the maximum rate of packets that can be transmitted over a connection.
Ethernet wire speed is 14,880 packets per second and Fast Ethernet wire
speed is 148,809 packets per second.
See also bit,
Ethernet,
Fast Ethernet,
packet.
Wireless Client is the term used in wireless networking for networked components such as desktop computers, notebook computers and peripheral devices such as printers and scanners.
Each Wireless Client
must be equipped with a network interface card (NIC) that supports wireless
connectivity. These NIC's may come in the form of PCI, ISA or EISA cards
for desktop computers; PCMCIA or PC cards for laptop and notebook computers;
and USB devices. In addition, the manufacturer of the NIC must provide
a device driver that enables the wireless client for network connectivity
with the required network operating system (NOS) such as NetWare or Microsoft
Networking. Once configured for the network, the wireless client uses
radio signals to communicate with the network by establishing a radio
link to an associated access point. Any wireless client can be added to
the network and placed in any location within the range of the access
point.
A collection of devices that work together to provide users with a non-wired means of networking. Our wireless technology consists of Access Points and network adapter cards (NICs) that can be used in PCs or USB compatible devices.
wizard
A Windows application that automates a procedure such as
installation or configuration.
Wireless Local
Area Network - A networked environment where users connect to other clients,
peripherals, the Internet or routing devices through a wireless connection.
Examples of WLANs include RF (radio frequency) and IR (infra red).
WWW
World Wide Web (or Web) is
an Internet service that allows easy access to information on servers
around the world. Web browsers such as Netscape Navigator and Internet
Explorer allow users to "browse the Web" in order to access this information.
WWW documents are structured using HTML (HyperText Mark-up
Language) and can incorporate JAVA and Javascript applications.
See also HTML,
Hypertext, Internet,
server.
xDSL
x Digital Subscriber Line.
This refers to different variations of DSL, for example ADSL.
See also ADSL,
DSL.
XNS
Xerox Network Services. An early networking protocol
developed by Xerox, that allows users (for example, someone working on
a PC) to use files that are on another computer.
See also network,
PC,
protocol.