2G Second-generation wireless network. 2G systems are Digital cellular telephone networks such as GSM.
2.5G Commonly used to describe enhancements to 2G networks, such as GPRS, which offer data services in addition to the existing voice services
3G Short for third-generation wireless, 3G refers to next-generation networks for personal and business wireless connectivity, especially mobile communications.
ANSI American National Standards Institute
AVAILABILITY Link availability is the percentage of time a link is useable when considering real-world causes for outage, such as climatic conditions, or outages due to equipment failure.
Availability is typically quoted in nines. For example, 99.9%, or (3x9's) availability, means on average, the link is expected to be not available 0.1% of the time, or an average of 8.76 hours per year. 99.99% (4x9's) translates into only 52.6 minutes of down-time and 99.999% (5x9’s) averages just 5.26 minutes of downtime per year.
BACKBONE The part of the communications network that connects main nodes, central offices or LANs.
BACKHAUL In general, transmitting data from remote locations to a point from which it can be distributed over a network. In wireless cellular/PCS networks, transmission links between cell sites and the system operator's switching centre.
BANDWIDTH In analogue communications, bandwidth referred to the width of the frequency range allocated for transmission.
In the digital world, it is more common to talk about bandwidth in terms of the number of bits transmitted per second (bps).
BER Bit Error Rate.
The bit error rate (BER) is a ratio of bad bits to total bits, used to measure data transmission integrity.
BIT Binary Digit.
Basic unit of digital data, represented as a one (1) or zero (0). Memory or data transferred per unit of time is measured in bits. Bits are lowercase (b) when used in abbreviations.
BROADBAND Originally, the term broadband meant to incorporate more than one channel into a communications transmission. Cable TV is also broadband because it carries many TV channels over one coax. Currently, broadband refers to communications technologies capable of transmitting more than 'narrowband' telephone connections, such as ADSL, at 256kbps.
BYTE Eight bits. Memory storage is measured in bytes. Bytes are uppercase (B) when used in abbreviations.
CARRIER A telephone or networking company that sells or rents telecommunication transmission services or capacity.
CDMA Code Division Multiple Access. A modulation method used in Wireless LAN and some cellular telephone networks to enable multiple users access to a single section of radio spectrum.
COST/BIT The cost to transmit one bit of data.
DARK FIBRE Refers to unlit and therefore unused Fibre-optic cable. Often, companies lay more Fibre lines than are needed at the time, and defer the cost until increased network traffic justifies the investment.
DWDM Dense Wavelength Division Multiplexing
An optical technology used to increase bandwidth over existing Fibre. DWDM combines and transmits multiple signals simultaneously at different wavelengths on the same Fibre.
EMI Electromagnetic Interference
Interference caused by a radio signal or other electromagnetic field.
ETHERNET A protocol for networking personal computers, and the most widely-used local area network (LAN) technology. Generally refers now to 10BASE-T systems, operating at 10 Mbps.
FAST ETHERNET Fast Ethernet is a local area network (LAN) transmission standard that provides a data rate of 100 megabits per second (referred to as "100BASE-T").
FDDI Fibre-Distributed Data Interface
A set of ANSI protocols for sending digital data over fibre optic cable. Typically used as a LAN backbone protocol.
FIXED WIRELESS The operation of wireless devices or systems in fixed locations such as homes and offices.
FSO Free Space Optics refers to the transmission of modulated visible or infrared beams through the atmosphere to obtain broadband communications. FSO systems can function over distances of several kilometers. As long as there is a clear line of sight between the source and the destination,
FULL DUPLEX A system which allows simultaneous transmission between two nodes on a network.
Giga (G) Engineering notation for one billion.
Gigabit One billion bits.
GIGABIT ETHERNET In data communications, a gigabit is one billion bits. A transmission technology based on the Ethernet frame format and protocol provides a data rate of 1 billion bits per second (one Gigabit). Gigabit Ethernet is carried primarily on optical fibre.
GIGABYTE One billion bytes
GPS Global Positioning System.
A system of low Earth orbiting satellites used to measure location on the ground or in the air, accurate to within about 10 meters for most receivers.
HALF DUPLEX A system where only one device can transmit data on a network at a time.
HFC Hybrid Fibre Coax
When the cable companies wanted to start providing services that required more capacity and distance than their coaxial cable networks could handle, they laid fibre in addition to coax. The resulting networks are referred to as HFC.
Kilo(K) Engineering notation for one thousand.
Mbps Megabits per second. Mbps stands for millions of bits per second or megabits per second and is a measure of the total information flow.
MTBF Mean Time Before Failure. A measure of reliability quoted by equipment manufacturers
MTTF Mean Time To Failure. A measure of reliability quoted by equipment manufacturers.
MTTR Mean Time To Repair. A measure of reliability
Mega(M) Engineering notation for one million.
OC-x Short for Optical Carrier; a prefix for SONET carrier hierarchies. See table below for specific speeds:
OC-1 51.84 Mbps
OC-3 155.52 Mbps
OC-12 622.08 Mbps
OC-24 1.244 Gbps
OC-48 2.488 Gbps
OC-192 9.95328 Gbps
OC-768 39.81312 Gbps
OPTICAL WIRELESS Free Space Optics (FSO), refers to the transmission of modulated visible or infrared (IR) beams to carry broadband communications. FSO systems can function over distances of several kilometres. As long as there is a clear line of sight LoS between the source and the destination.
OSI Open Systems Interconnect
The OSI model for communications protocols is a global ISO standard for communications that contains protocols in seven layers. Control is passed from one layer to the next, starting at one end, proceeding through the layers to the other and back again:
Layer 7 - Application Layer Connects an application or program to a communications protocol
Layer 6 - Presentation Layer Encodes and decodes the data to be transmitted
Layer 5 - Session Layer Establishes and maintains connection to the communications processes in the lower layers
Layer 4 - Transport Layer Responsible for error correction and direction of flow
Layer 3 - Network Layer Switching and routing layer
Layer 2 - Data-link Layer Receives and transmits data over the physical layer
Layer 1 - Physical Layer The transmission medium itself (copper cable twisted pair, fibre, FSO)
PROTOCOLS A set of processes and rules that communications equipment use to transfer data.
RELIABILITY Refers to the expected failure rate of the equipment. Typical parameters quoted are MTBF, MTTF or MTTR.
ROUTER A router is a device or, in some cases today, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination.
SDH Synchronous Digital Hierarchy
Standardized by the ITU, SDH is a family of digital carrier rates. SDH is the term used by the ITU to refer to SONET OC rates, as they are called in the United States. The basic SDH building block is a rate of 155.52 Mbps, called STM-1.
SNMP Simple Network Management Protocol
A standard for network management across network management systems and network components. Another definition is: Protocol that governs network management and monitoring of network devices and their functions.
SONET Synchronous Optical Network
SONET has become an ANSI (American National Standards Institute) standard as well as an ITU international standard named SDH that defines interface standards at the physical layer 1 level.
SPREAD SPECTRUM A modulation technology which 'spreads' transmitted signals over a wide portion of the RF spectrum, to provide immunity to same-channel, co-channel and multipath interference, and enable spectral re-use. Widely used in Wireless LANs
STM Synchronous Transfer Mode
STS Synchronous Transport Signals; the electrical version of OC (Optical Carrier)
TELCO An abbreviation for telephone company, usually applied to the network operator
TRANSCEIVER A combination of transmitter/receiver in a single unit
UMTS Universal Mobile Telephone System. Another name for 3G
WDM Wavelength Division Multiplexing
Technology developed for multiplexing several signals onto a single optical fibre.
WIRELESS LAN Wireless Local Area Network. Most commonly, using the unlicensed spectrum.
WLAN Short for Wireless LAN