|
100BaseT
- The ethernet networking standard that supports a data transmission
rate of 100 Mbps and is backward compatible to 10BaseT.
|
|
10BaseT
- The ethernet networking standard that supports a data transmission
rate of 10 Mbps.
|
|
2B1Q (Two
Binary, One Quaternary) - A line coding technique used in
traditional telecommunications offerings including ISDN.
|
|
Access Network
- That portion of a public switched network that con- nects
access nodes to individual subscribers. The Access Network today
is predominantly passive twisted pair copper wiring.
|
|
Access Nodes
- Points on the edge of the Access Network that concentrate
individual access lines into a smaller number of feeder lines.
Access Nodes may also perform various forms of protocol conversion.
Typical Access Nodes are Digital Loop Carrier systems concentrating
individual voice lines to T1 lines, cellular antenna sites, PBXs,
and Optical Network Units (ONUs).
|
|
Access Point
- The network hub device for a wireless network.
|
|
ADSL
(Asymmetric Digital Subscriber Line) - Modems attached
to twisted pair copper wiring that transmit from 1.5 Mbps to 9
Mbps downstream (to the sub- scriber) and from 16 kbps to 800
kbps upstream, depending on line distance.
|
|
ADSL Lite
- Nickname for G.lite. DSL based on the new G.lite standard that
supports 1.5 Mbps downstream and 348 upstream.
|
|
ANSI (American
National Standards Institute) - The organization that defines
standards for the United States.
|
|
APON
(ATM Passive Optical Network) - A passive optical network
running ATM.
|
|
ATM (Asynchronous
Transfer Mode) - An ultra high speed cell based data transmission
protocol which may be run over ADSL.
|
|
ATM 25
- ATM Forum defined 25.6Mbit/s cell based user interface based
on IBM token ring network.
|
|
ATU-C and
ATU-R (ADSL Transmission Unit, Central or Remote) -
The device at the end of an ADSL line that stands bet- ween the
line and the first item of equipment in the subscriber premises
or telephone switch. It may be integrated within an access node.
|
|
AWG (American
Wire Guage) - A measure of the thickness of copper, aluminum
and other wiring in the U.S. and other countries.
|
|
Backbone
- A major transmission path used for high-volume network-to-network
connections.
|
|
Bandwidth
- The amount of data that can flow through a given communications
channel.
|
|
BDSL (Same
as VSDL B-ISDN Broadband Integrated Digital Network)
- A digital net- work with ATM switching operating at data rates
in excess of 1.544 or 2.048 Mbps. ATM enables transport and switching
of voice, data, image, and video over the same infrastructure.
|
|
BERT
(Bit Error Rate Test) - A test that reflects the ratio
of error bits to the total number transmitted.
|
|
Binary
- A number system based on 2. The binary to decimal conversions
make up the IP addresses used on any TCP/IP network.
|
|
B-ISDN
(Broadband Integrated Digital Network) - A digital network
with ATM switching operating at data rates in excess of 1.544
or 2.048 Mbps.
|
|
Bit -
The single unit of data used in digital data communications.
|
|
Bps (Bits
per second) - The unit of measurement for data transmission
speed over a data communications link.
|
|
BRI (Basic
Rate Interface) - This is an ISDN interface typically used
by smaller sites and customers.
|
|
Bridge
- A device that connects two networks as a seamless single network
using the same networking protocol. DSL modems are typically bridges.
|
|
Bridge Tap
- An extension to a local loop generally used to attach a remote
user to a central office switch without having to run a new pair
of wires all the way back.
|
|
Broadband
- A term used to describe a high-capacity network that can carry
several services on the same line, such as data, voice, and video.
|
|
Byte
- A unit of data consisting of 8 bits.
|
|
Cable Binder
- A bundle of local loop wires that runs along telephone poles
or underground from the CO.
|
|
CAP (Carrierless
Amplitude) - A version of QAM in which incoming data modulates
a single carrier that is then transmitted down a telephone line.
|
|
CAT5
- Category 5 unshielded twisted-pair wiring commonly used for
10BaseT and 100BaseT Ethernet networks.
|
|
CATV
(Community Access Television) - Also known as Cable TV.
|
|
CBR -
Constant Bit Rate.
|
|
CCITT
- Consultative Committee for International Telegraph and Telephone.
|
|
Channel
- A path for digital transmission signals.
|
|
CIDR
(Classless Internet Domain Routing) - CIDR allows IP addresses
to be broken down into smaller subnets than the class C network,
with 256 IP addresses.
|
|
Circuit
- A path through a network from source to destination and back.
|
|
CLEC
- Competitive Local Exchange Carrier. A competitor to ILECs offering
telecommunications service.
|
|
Client -
A program of a device that requests services from a server.
|
|
Client/Server - A style of computer networking that
allows work to be distributed across powerful computers acting
as servers and client computers.
|
|
CO (Central
Office) - A circuit switch that terminates all the local access
lines in a particular geographic serving area; a physical building
where the local switching equipment is found.
|
|
CODEC
(Abbreviation for coder/decoder) - Specifically it converts
a voice grade analog signal to u-law or a-law encoded samples
at an 8KHz sampling rate. Consists of a single 16 Kbps data channel plus 2 bearer channels
for voice and/or data.
|
|
Core Network
- Combination of switching offices and transmission plant
connecting switching offices together. In the U.S. local exchange
Core Networks are linked by several competing Interexchange networks;
in the rest of the world (now) the Core Network extends to national
boundaries.
|
|
CPE (Customer
Premise Equipment) - A wide range of customer-premises terminating
equipment which is connected to the local telecommunications network.
This includes telephones, modems, terminals, routers, settop boxes,
etc.
|
|
Crosstalk
- The interference induced on a signal on one line that is caused
by the transfer of energy from a co-located line.
|
|
CSA (Carrier
Serving Area) - Area served by a LEC, RBOC or telco, often
using Digital Loop Carrier (DLC) technology.
|
|
CSMA/CD
(Carrier Sense Multiple Access/Collision Detection) - A
network transmission scheme in which multiple network devices
can transmit across the cable simultaneously.
|
|
CSU -
Channel Service Unit.
|
|
Data CLEC
- A Competitive Local Exchange Carrier that focuses on IP data
communications links and doesn't provide traditional voice telecommunications.
|
|
DCE -
Data Communication (or Circuit-Terminating) Equipment.
|
|
Default Gateway
- The address that the IP uses if the destination address is not
on the local subnet.
|
|
Demarcation
Point - The point at the customer premises where the line
from the telephone company meets the premises wiring.
|
|
DHCP
(Dynamic Host Configuration Protocol) - A protocol that
allows IP addressing information to be dynamically assigned by
a server to clients on an as-needed basis.
|
|
Dial-Up Networking
- Used in Windows '95, '98, NT, and 2000 for making PPP dial-up
modem connections to the internet.
|
|
DLC (Digital
Loop Carrier) - A telecommunications structure deployed wherever
an ILEC needs more capacity.
|
|
DMT (Discrete
Multi-Tone) - An ADSL modulation technique standardized by
the ANSI.
|
|
DNS (Domain
Name System) - The name resolution service for IP addresses
that provides the friendlier text-based addresses for internet
resources.
|
|
DNS Service
(Domain Name System Service) - The configuration of user-friendly
text domain names to IP addresses by an ISP using DNS.
|
|
Domain Name
- The user-friendly text name used instead of a numeric IP address
for an internet address.
|
|
Domain Name
Server - A program that converts an FQDN into its numeric
IP address, and vice versa.
|
|
Downstream - The direction of data flow on a data communications
link that occurs from the network down to the user.
|
|
DS0 (Digital
Signal 0) - 64 Kbps digital representation of voice.
|
|
DS1 (Digital
Signal 1) - Twenty four voice channels packed into a 193 bit
frame and transmitted at 1.544 Mbps. The un- framed version, or
payload, is 192 bits at a rate of 1.536 Mbps.
|
|
DS2 (Digital
Signal 2) - Four T1 frames packed into a higher level frame
transmitted at 6.312 Mbps.
|
|
DSL (Digital
Subscriber Line) - The generic term that refers to the underlying
technology inherent in all flavors of DSL, such as ADSL, SDSL,
and HDSL.
|
|
DSL Bridge
- A device that combines one or more networks into a single seamless
network.
|
|
DSL Modem
- A common term used for a DSL bridge.
|
|
DSLAM
(Digital Subscriber Line Access Multiplexer) - A device
which takes a number of ADSL subscriber lines and concentrates
these to a single ATM line.
|
|
DSU (Data
Service Unit) - A digital interface device that connects end
user data communications equipment to the digital access lines
which provides framing of sub-64Kbps customer access channels
onto higher rate data circuits. A DSU may be combined with a CSU
into a single device called a CSU/DSU. See Channel Service Unit/Data
Service Unit.
|
|
DTE (Data
Terminal Equipment) - Typically the device that transmits
data such as a personal computer or data terminal.
|
|
Dynamic IP
Addressing - An IP address is assigned to the client for the
current session or some other specified amount of time.
|
|
E1 -
European basic multiplex rate which packs thirty voice channels
into a 256 bit frame and transmitted at 2.048 Mbps.
|
|
Echo Suppressor
- An active device used by the phone company to suppress positive
feedback (singing) on the phone network.
|
|
EIA (Electronic
Industries Association) - An organization that provides standards
for the data communications industry.
|
|
EMI -
Electromagnetic Induction
|
|
Ethernet
- A LAN technology that uses CSMA/CD delivery and can run over
different media (cabling).
|
|
Ethernet
Address - The unique hardware address that identifies any
ethernet device.
|
|
ETSI -
European Telecommunications Standards Institute.
|
|
FCC (Federal
Communications Commission) - The U.S. government agency for
regulating the telecommunications industry.
|
|
FDM -
Frequency Division Multiplexing.
|
|
FDQN
(Fully Qualified Domain Name) - The full name of a host,
including all subdomain and domain names.
|
|
Feeder Network
That part of a public switched network which connects access nodes
to the core network.
|
|
FEXT
(Far End CrossTalk) - The interference occurring between
two signals at the end of the lines remote from the telphone switch.
|
|
Fiber Optics
- A technology in which light is used to transport large amounts
of data using thin filaments of glass.
|
|
Firewall
- A security device (hardware or software) that controls access
from the internet to a local network.
|
|
Firmware
- Instructions stored in memory that controls a device, such as
a DSL modem or router.
|
|
Fractional
T-1 - Any data transmission rate between 56Kbps and 1.54 Mbps
(which is the full T-1 rate).
|
|
Frame Relay
- A dedicated, public networking service offered by telecommunication
companies for LAN-to-LAN connections.
|
|
FTTC
(Fiber to the Curb) - Network where an optical fiber runs
from the telephone switch to a curbside distribution point close
to the subscriber where it is converted to copper pair.
|
|
FTTCab
(Fiber to the Cabinet) - Network architecture where an
optical fiber connects the telephone switch to a street-side cabinet
where the signal is converted to feed the subscriber over a twisted
copper pair.
|
|
FTTH
(Fiber to the Home) - Network where an optical fiber runs
from the telephone switch to the subscriber's premises.
|
|
FTTK or FTTC
(Fiber To the Kerb) - Anetwork where an optical fiber runs
from telephone switch to a kerbside distribution point close to
the subscriber where it is converted to a copper pair.
|
|
G.dmt
- A standards-based form of ADSL that supports up to 8 Mbps downstream
and 1.54 Mbps upstream.
|
|
G.lite
- The new ITU standard that forms the basis of Universal ADSL,
which supports 1.5 Mbps downstream and 384 upstream.
|
|
Gateway
- A functional device that allows equipment with different protocols
to communicate with each other.
|
|
Hardware
Address - The physical address for the NIC, which is used
by low-level hardware layers of the network, including DSL bridges.
|
|
HDSL
(High-bit-rate Digital Subscriber Line) - The DSL service
widely used for T-1 lines. HDSL uses four wires (two pairs) instead
of the standard two wires used for other DSL flavors. Supports
symmetrical service at 1.54 Mbps but doesn't support POTS.
|
|
HFC (Hybrid
Fiber Coax) - A system (usually CATV) where fiber is run to
a distribution point close to the subscriber and then the signal
is converted to run to the subscriber's premises over coaxial
cable.
|
|
HomePNA
(Home Phoneline Networking Alliance) - The group that created
the specifications for Phoneline networking, which uses telephone
wiring as network cabling.
|
|
HomeRF
(Home Radio Frequency) - A wireless networking specification
that uses the 2.4-GHz band.
|
|
Host
- A computer or any device connected to a TCP/IP network.
|
|
Hub -
A passive network device that repeats all data traffic to all
ports. A hub is at the center of a LAN.
|
|
IDSL
(ISDN Digital Subscriber Line) - The always-on cousin of
dial-up ISDN. IDSL delivers a symmetric 144 Kbps of bandwidth,
which is 16 Kbps more than the dial-up version of ISDN.
|
|
IEC -
Inter-Exchange Carrier
|
|
IEEE
(Institute of Electrical and Electronics Engineers) - A
worldwide engineering and standards-making body for the electronics
industry.
|
|
IETF
(Internet Engineering Task Force) - The organization that
provides the coordination of standards and specification development
for TCP/IP networking.
|
|
ILEC
(Incumbent Local Exchange Carrier) - A new term that emerged
from the Telecommunications Act of 1996 that describes the traditional
local telephone companies.
|
|
IMAP4
(Internet Message Access Protocol, Version 4) - IMAP4 provides
sophisticated client/server capabilities beyond the features of
POP3.
|
|
Internet
Address - The unique 32-bit numeric address used by a host
on a TCP/IP network.
|
|
Intranet
- A local network that uses TCP/IP and Web technologies as its
networking protocol.
|
|
IP -
Internet Protocol. The connectionless network layer protocol that
forms the networking functions of the TCP/IP suite.
|
|
IP address
- Internet Protocol Address. A 32-bit dotted decimal notation
used to represent IP addresses.
|
|
IPSec
- A virtual private networking protocol that is part of the IPv6
but is widely used now in IPv4.
|
|
IPv4
- The current version of IP addressing based on 32-bit IP addresses.
|
|
IPv6
- The next generation of IP addressing based on 64-bit IP addresses
and having a number of enhancements over IPv4.
|
|
ISDL
- Uses ISDN transmission technology to deliver data at 128kbps
into an IDSL "modem bank" connected to a router.
|
|
ISDN
(Integrated Services Digital Network) - Gives a user up
to 56Kbps of data bandwidth on a phone line that is also used
for voice, or up to 128 Kbps if the line is only used for data.
|
|
ISO -
International Organization for Standards.
|
|
ISP (Internet
Service Provider) - An entity that provides commercial access
to the Internet. These can range in size from someone operating
dial-up access with a 56 kilobit line and several dozens of customers
to providers with multiple pops in multiple cities and substantial
backbones and thousands or even tens of thousands of customers.
|
|
ITU -
International Telecommunications Union. The ITU is an international
body of member countries that defines recommendations and standards
relating to international telecommunications.
|
|
IXC (Inter-exchange
Carrier) - Post-1984 name for long distance phone companies
in the United States. AT&T is the largest, followed by MCI
and Sprint, but several more small IXCs exist.
|
|
Kbps
(Kilobits per second) - A measurement of digital bandwidth
where one Kbps equals one thousand (actually 1024) bits per second.
|
|
L2TP
(Layer 2 Tunneling Protocol) - An IETF protocol used for
virtual private networking.
|
|
LADC
- Local Area Data Circuit.
|
|
LADS
- Local Area Data Service.
|
|
LAN (Local
Area Network) - A data network that connects computers in
an area usually within the confines of a building or floors within
a building.
|
|
LEC (Local
Exchange Carrier) - One of the new U.S. telephone access and
service providers that have grown up with the recent U.S. deregulation
of telecommunications.
|
|
Last Mile
- The telephone line between a local telephone company switching
facility and the customer premises.
|
|
LATA
(Local Access and Transport Area) - This was created by
the 1984 divestiture and defines the geographic area over which
the LEC may provide toll calls.
|
|
Latency -
A measure of the delay between the sending of a packet at the
originating end of a connection and the reception of that packet
at the destination end.
|
|
Layer
- In the OSI network reference model, each layer performs a certain
task to move the data from the sender to the receiver.
|
|
Loading Coil
- A metallic, doughnut-shaped device used on local loops to extend
their reach.
|
|
LOCAL LOOP - A pair of wires, moderately twisted for the
entire length between the telephone company's end office and the
user premises (the common telephone set) form a loop, so it is
referred to as the local loop. This loop provides a user with
access to the global telecommunications infrastructure that is
installed all over the world. The local loop has been historically
designed to provide voice grade audio service. The circuit is
powered from the central office with 48V (open circuit voltage)
limited in current to a value somewhat higher than 20mA. This
current is used for signaling phone access, burning off moisture,
breaking through metalic oxides caused by corrosion, and powering
a carbon microphone. The original telephone equipment contained
no active electronics. The actual wiring of the local loop may
be considered to be a lossy transmission line. DSL uses whatever
frequencies will propagate on this line for purposes of digital
data transmission. T1 modulation (alternate mark inversion) has
been doing this for years. DSL extends the capability by using
modern technology to increase the data rates and distances spanned.
|
|
Loop Qualification
- The process of determining if a line (or loop) will support
a specific type of DSL transmission at a given rate.
|
|
MAC Address
(Media Access Control address) - The 48-bit defined number
built into any ethernet device connected to a LAN.
|
|
Mbps
(Mega bits per second) - A measurement of digital bandwidth
where one Mbps equals just over one million bits per second.
|
|
MDF (Main
Distribution Frame) - The point where all local loops are
terminated at a CO.
|
|
Modulation - A prescribed method of encoding digital
(or analog) signals on a different waveform (the carrier signal).
Once encoded, the original signal may be recovered by an inverse
process, demodulation. Modulation is performed to adapt the signal
to a different frequency range (and medium) than that of the original
signal
|
|
MPEG
(Motion Picture Experts Group) - The group that has defined
the standards for compressed video transmission.
|
|
MPOE
(Minimum Point of Entry) - The place where phone lines first
enter a customer's facility.
|
|
Multiplexer - Any one of a number of common devices
used to combine multiple telecommunications circuits into channels.
|
|
MVL -
Multiple Virtual Lines. A DSL technology developed by Paradyne.
MVL transforms a single copper loop into multiple virtual lines
to support multiple independent services over the same line simultaneously.
|
|
NAP (Network
Access Provider) - Another name for the provider of net- worked
telephone and associated services, usually in the U.S.
|
|
NAT (Network
Address Translation) - The translation of an Internet Protocol
address (IP address) used within one network to a different IP
address known within another network. One network is designated
the inside network and the other is the outside. Typically, a
company maps its local inside network addresses to one or more
global outside IP addresses and unmaps the global IP addresses
on incoming packets back into local IP addresses. This helps ensure
security since each outgoing or incoming request must go through
a translation process that also offers the opportunity to qualify
or authenticate the request or match it to a previous request.
NAT also conserves on the number of global IP addresses that a
company needs and it lets the company use a single IP address
in its communication with the world.
|
|
NDIS (Network
Driver Interface Specification) - Developed by Microsoft to
provide a common set of rules for network adapters to interface
with operating systems.
|
|
NEBS
- Network Equipment Building Standards.
|
|
NEXT
(Near-end Crosstalk) - Interference between pairs of lines
at the telephone switch end.
|
|
N-ISDN
(Narrowband ISDN) - Same as ISDN.
|
|
NIC (Network
interface card) - The hardware that forms the interface between
the computer (or other network device) and not only the data communications
network for the LAN but also the IP connection through a DSL ethernet
bridge or router.
|
|
NID (Network
interface device) - A device that terminates a copper pair
from the serving central office at the user's destination.
|
|
NNTP
(Network News Transport Protocol) - The protocol that governs
the transmission of network news, a threaded messaging system
for posting messages to form newsgroup discussions.
|
|
NSP (Network
service provider) - Any company that provides network services
to subscribers.
|
|
NTE (Network
Termination Equipment) - The equipment at the ends of the
line.
|
|
OC3 (Optical
Carrier 3) - An optical fiber line carrying 155 Mbps; A U.S.
designation generally recognized throughout the telecommunications
community worldwide.
|
|
ONU (Optical
Network Unit) - A form of access node that converts optical
signals transmitted via fiber to electrical signals that can be
transmitted via coaxial cable or twisted pair copper wiring to
individual subscribers.
|
|
OSI (Open
Systems Interconnection) - An internationally accepted model
of data communication protocols developed by OSI and ITU.
|
|
Packet
- A fixed-or-variable sized unit of information that can be sent
across a packet-switching network.
|
|
Packet CLEC
- A Competitive Local Exchange Carrier that focuses on providing
data communication services instead of voice services.
|
|
Packet Filter
- The capability to search a packet to determine its destination
and then route or block it accordingly.
|
|
Packet Switching
- A data transmission method in which data is transferred by packets,
or blocks of data.
|
|
Packet-Switched Network - A network that does not establish
a dedicated path through the network for the duration of a session
but instead transmits data in units called packets in a connectionless
manner.
|
|
PBX -
Public Branch Exchange.
|
|
PC Card
- The credit-card-size adapter cards used in notebooks. A DSL
modem for a notebook can be a PC Card.
|
|
PCI (Peripheral
Component Interconnect) - A specification introduced by Intel
that defines a local bus system that allows up to ten PCI-compliant
expansion cards in a PC.
|
|
PCM -
Pulse Code Modulation.
|
|
Phoneline
Network - A networking technology based on the HomePNA specification
that uses telephone wiring as network cabling.
|
|
PnP (Plug-and-Play)
- A system for simplifying installation of hardware devices on
a Microsoft Windows computer.
|
|
PON (Passive
Optical Network) - The usual acronym for a fiber based transmission
network containing no active electronics.
|
|
POP
(Point of Presence) - A node of an ISP containing a DSU-CSU,
terminal server and router and sometimes one or more hosts, but
no network information center or network operations center.
|
|
POP3
(Post Office Protocol, Version 3) - The latest version
of the Post Office Protocol, POP3 provides basic client/server
features for handling email.
|
|
POTS
(Plain Old Telephone Service) - The only name recognized around
the world for basic analog telephone service. POTS takes the lowest
4kHz of bandwidth on twisted pair wiring. Any service sharing
a line with POTS must either use frequencies above POTS or convert
POTS to digital and interleave with other data signals.
|
|
PPP (Point-to-Point
Protocol) - A communications protocol that allows a computer
using TCP/IP to connect directly to the internet through a dial-up
connection.
|
|
PPPoA
(Point-to-Point Protocol over Asynchronous Transfer Mode)
- ATM is a high-speed switching technique used to transmit high
volumes of voice, data, and video traffic.
|
|
PPPoE
(Point-to-Point Protocol Ethernet) - A standard that enables
dial-up networking capabilities over ethernet.
|
|
PPTP
(Point-to-Point Tunneling Protocol) - The VPN client software
solution included with Microsoft Windows 95, 98, NT, and 2000.
|
|
PRI (Primary
Rate Interface) - This is an ISDN interface typically used
by larger users.
|
|
Protocol
- A set of rules that defines how different systems interoperate.
|
|
PSTN
(Public Switched Telephone Network) - The network that
provides global telephone service.
|
|
PTT (Postal,
Telegraph and Telephone) - The generic European name usually
used to refer to state-owned telephone companies.
|
|
PUC (Public
Utilities Commission) - A United States government agency,
usually at the state level, that regulates telecommunication companies
and other utilities.
|
|
PVC (Permanent
Virtual Circuit) - Connection-oriented circuit that may be set
up by software between any two nodes of a switched network.
|
|
QAM -
Quadrature Amplitude Modulation
|
|
QoS (Quality
of Service) - A definition of a given level of service for
voice or data communication services by a provider.
|
|
RADSL
(Rate Adaptive Digital Subscriber Line) - A version of ADSL
where modems test the line at start up and adapt their operating
speed to the fastest the line can handle.
|
|
RBOC
(Regional Bell Operating Company) - One of the seven U.S.
Telephone companies that resulted from the break up of AT&T.
|
|
RJ-11
- A standard modular connector that can support two pairs of wires
(four wires). RJ-11 connectors are used for most PSTN CPE (telephones,
faxes, and modems).
|
|
RJ-45
- A standard modular connector that can support up to four pairs
of wires (eight wires). RJ-45 connectors are used with category
5 cabling used with 10BaseT or 100BaseT cabling.
|
|
Router
- A device that routes data between networks through IP addressing
information contained in the header of the IP packet.
|
|
SDSL
(Symmetric Digital Subscriber Line) - HDSL plus POTS over
a single telephone line. This name has not been adopted by a standards
group, but is being discussed by ETSI. It is important to distinguish,
however, as SDSL operates over POTS and would be suitable for
symmetric services to premises of individual customers.
|
|
Server
- A host that makes an application or a service available to other
hosts, typically clients.
|
|
SMTP (Simple
Mail Transfer Protocol) - SMTP is the protocol for internet
email that transfers email messages among computers.
|
|
SNR -
Signal-to-Noise Ratio.
|
|
Splitter
- A device used to separate POTS service from the ADSL data service
at a customer's premises.
|
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SSL (Secure
Socket Layer) - SSL version 2 provides security by allowing
applications to encrypt data that goes from a client, such as
web browser, to a matching server.
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Static IP
Addressing - An assigned IP address used to connect to a TCP/IP
network. The IP address stays with the specific host or network
device.
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STP (Shielded
twisted pair) - A shielded form of the twisted-pair wiring
used for 10BaseT and 100BaseT LANs.
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STS-1
- SONET basic transmission rate of 51.84 Mbps.
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Subnet
- A portion of a network. Each subnet within a network shares
a common network address and is uniquely identified by a subnetwork
number.
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Subnet Mask
- A 32-bit number used to separate the network and host sections
of an IP address.
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SVC (Switched
Virtual Circuit) - A term found in frame relay and ATM networking
in which a virtual connection, with variable end-points, is established
through an ATM network at the time the call is begun.
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T1 -
A North American standard for communicating at 1.54 Mbps. A T-1
line has the capacity for 24 voice and data channels at 64 Kbps
each.
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T3 -
A North American standard for communicating at speeds of 44 Mbps.
A T-3 line has 672 channels for voice and data at 64 Kbps each.
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TCP (Transmission
Control Protocol) - One of two principal components of the
TCP/IP protocol suite. TCP puts data into packets and provides
packet delivery across the network, ensuring that packets are
not lost in transmission and arrive in order.
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TCP/IP
(Transmission Control Protocol/Internet Protocol) - TCP/IP
is the suite of protocols that define the basis of the internet.
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TCP/IP stack
- The software that allows a computer to communicate through TCP/IP.
Stack refers to the fact that five layers of protocols operate
on a TCP/IP network.
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TDM -
Time Division Multiplexing.
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Telco
(Telephone Company) - Generic name for telephone companies
throughout the world which encompasses RBOCs, LECs, and PTTs.
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Telnet
- A terminal-emulation protocol that allows you to access computers
and network devices through TCP/IP.
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TPON (Telephony
over Passive Optical Network) - Telephony using a PON as all
or part of the transmission system between telephone switch and
subscriber.
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Twisted Pair
- A cable comprised of pairs of wires twisted around each other
to help cancel out interference.
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UART (Universal
Asynchronous Receiver/Transceiver) - The older serial port
architecture for data communications that is limited to 115-Kbps
capacity.
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UBR -
Unspecified Bit Rate.
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UDSL
- Unidirectional HDSL as proposed by one company in Europe without
much sign of interest from anyone else.
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USB (Universal
Serial Bus) - A new data communications port installed on
most newer PCs to replace the UART serial port.
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UTP
(Unshielded twisted pair) - Cabling used for 10BaseT and 100BaseT
LANs. UTP consists of pairs of copper wires twisted around each
other and covered by plastic insulation.
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VaDSL
- Very high speed ADSL. Same as VDSL.
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VBR -
Variable Bit Rate.
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VDSL
(Very high bit-rate Digital Subscriber Line) - Modem for
twisted pair access operating at data rates from 12.9 to 52.8
Mbps with corresponding maximum reach ranging from 4500 to 1000
feet of 24-gauge twisted pair.
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VoDSL
(Voice over DSL) - A hybrid voice communication system
that enables digital voice communications over a DSL network and
then passes the voice to PSTN.
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VoIP
(Voice over IP) - Forms the basis of PC-to-PC voice communications
over the internet.
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VPN (Virtual
Private Network) - A way that private data can safely pass
over a public network, such as the internet. The data traveling
between the two hosts is encrypted for privacy, and other security
features are included to provide a secure direct connection over
the internet.
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WAN (Wide
Area Network) - A data network typically extending a LAN outside
a building over a data communications link to another network
in another location.
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Web Hosting
- A service performed by an ISP or a web hosting service that
operates all the web server infrastructure for you.
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xDSL
- A generic term used to refer to the entire family of DSL technologies.
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