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A
 
Sundries
 
10 Base-T
Twisted-pair cable with maximum segment lengths of 100 meters.
100 Base-T
The 100-Mbps baseband Ethernet specification uses two pairs of twisted-pair wire with a maximum
distance of 100 meters between the hub and the workstation.
10Base-S Mode
This is a VDSL mode. Each mode operates in a specific frequency band allocation with associated
upstream and downstream speeds.
2B1Q(Two Binary, One Quarternary )
Two Binary, One Quarternary transmission is an amplitude modulation scheme for DC pulses. It
combines two bits at a time to represent one of four amplitude levels. 2B1Q coding is defined in
ANSI T1.601 and ETR 080, Annex A.
802.1Q(IEEE 802.1Q VLAN)
802.1Q is an IEEE standard for tagged VLANs (Virtual LANs) in which a VLAN ID is inserted
into the layer-2 frame header to allow the creation of dynamic VLANs across switches. Tagged
VLANs are not confined to the switch on which they were created as are port-based VLANs.
 
A
A-end (IPSec)
This is the end of a VPN tunnel opposite the Z-end (see also Z-end).
A-Law
A-Law and Mu-Law are Pulse Code Modulation (PCM) techniques that dictate forms of compression
for audio signals. They are widely-used standard methods of coding voice as they improve signal-to-noise
ratio without increasing the amount of data. Mu-Law is a standard in North America; A-Law in Europe.
AAL(ATM Adaptation Layer)
AAL converges packets from upper layers into ATM cells as defined by ITU-T, ETSI and the ATM
Forum. AAL has several service types and classes of operation to accommodate different types of classes.
AAL-2(ATM Adaptation Layer - type 2)
A connection oriented, VBR (Variable Bit Rate) protocol for real-time applications. It is similar to T1
or T3 and provides a variety of data rates. See AAL.
AAL-5(ATM Adaptation Layer - type 5)
A UBR (Unspecified Bit Rate) protocol that provid spare bandwidth to non-critical services such as
file transfers. See AAL.
ABR(Available Bit Rate)
This is a guaranteed minimum data transfer rate. Higher rates are allowed if there is extra bandwidth
available on the network.
Access Line
This is the physical telecommunications circuit (line) in the local network that connects the CO (Central Office)
with the customer's residence. See also Local Loop.
Access Point
An Access Point (AP) is a network device that acts as a bridge between a wired and a wireless network.
Account Generator Printer(Account Generator Printer)
When connected to an Internet service gateway device, an account generator printer allows you to create and
print out subscriber accounts automatically. The account generator printer is also known as the statement printer.
Acknowledged Alarms
This means that an administrator has decided to handle the cause of this alarm. Other administrators
see that person's name in their alarm screen, thus avoiding duplicate effort to solve the same problem.
Active Alarms
"Active" is the initial state of an alarm, which means the alarm is new and an administrator is yet to
assume responsibility for handling it.
Ad-Hoc(Ad-Hoc wireless LAN)
An Ad-Hoc wireless LAN is a group of computers that uses wireless LAN cards, to connect as an
independent wireless LAN. An Ad-Hoc wireless LAN is sometimes referred to as a Basic Service Set (BSS).
ADPCM(Adaptive Differential Pulse Code Modulation)
ADPCM-32 is a 32-bit voice compression method that converts analog signals to digital data, thus
allowing voice transmission over digital lines
ADSL(Asymmetrical Digital Subscriber Line )
This is an asymmetrical technology which means that the downstream data rate of the line is much
higher than the upstream data rate. ADSL operates in a frequency range that is above the frequency
range of voice services, so both can operate over the same cable.
AES(Advanced Encryption Standard)
Advanced Encryption Standard is method of data encryption that uses a secret key. AES may use
a 128-bit, 192-bit or 256-bit key. AES is faster than 3DES.
Aggressive Mode
Aggressive mode is an IPSec phase 1 negotiation mode (see Negotiation Mode). Aggressive
mode is quicker than Main Mode because it eliminates several steps. However the faster speed
limits its negotiating power and it also does not provide identity protection. See also Main Mode.
AH(Authentication Header)
Authentication Header (RFC 2402) is a protocol that IPSec uses to verify integrity of a data
packet (including the header) and the identity of it's ender.
Always-on
Always-on refers to broadband services that are connected all the time, eliminating the need to dial-up to connect.
Analog
An electrical circuit that is represented by means of continuous, variable physical quantities (such as voltages
and frequencies), as opposed to discrete representations (like the 0/1, off/on representation of digital circuits).
ANSI(American National Standards Institute)
ANSI is the primary organization for fostering the development of technology standards
(defining coding standards and signaling schemes) in the United States.
ANSI Mode
This is a VDSL mode that operates in a specific frequency band allocation with associated upstream
and downstream speeds.
Antenna
An antenna acts as a radiator that propagates a radio frequency signal from a wireless device
through the air. An antenna also works in reverse by capturing signals from the air.
ARP(Address Resolution Protocol)
Address Resolution Protocol is a protocol for mapping an Internet Protocol address
(IP address) to a physical computer address that is recognized in the local network.
ASIC(Application Specific Integrated Circuit)
This is a chip engineered for a particular use or function.
AT&T 5ESS
A digital central office switching system made by AT&T.
ATM(Asynchronous Transfer Mode. )
ATM is a LAN and WAN networking technology that provides high-speed data transfer.
ATM uses fixed-size packets of information called cells. With ATM, a high
QoS (Quality of Service) can be guaranteed.
ATM25
ATM25 is a 25.6 Mbps cell-based user interface defined by the ATM Forum.
ATU-C(ADSL Transmission Unit-CO)
This is the hardware at the CO (Central Office) that terminates an ADSL connection.
ATU-R(ADSL Transmission Unit-Remote)
This is the hardware at a customer's location that provides termination for an ADSL connection.
Authentication Algorithm
This is an established, step-by-step procedure for verifying the identity of a packet's ender.
Authenticity
Proof that the information came from the person or location that reportedly sent it. One
example of authenticating software is through digital signatures.
Auto-crossover
An auto-crossover Ethernet port enables you to use either a crossover Ethernet cable or
a straight-through Ethernet cable to connect your device to either a computer or external hub.
In other words these ports automatically adjust according to the type of cable so that either
straight-through Ethernet cable or crossover Ethernet cable may be used.
Auto-MDI/MDIX(Auto-MDI (Medium Dependent Interface)/MDIX (MDI crossover))
Auto-MDI (Medium Dependent Interface)/MDIX (MDI crossover) is an Ethernet port feature
that automatically adjusts to crossover or straight-through Ethernet cable so you can use either
to connect your device to a computer or a switch/external hub. See also auto-crossover.
Auxiliary Port
This port can be used as a traditional dial-up connection in reserve if ever the broadband connection
to the WAN port fails. See also Dial Backup.
 
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