Some Glossary and Definitions

3G	Third Generation Wireless technology offers support for very high speed data transmission rates. This supports real-time multimedia applications.
APN	An Access Point Name (APN) is assigned to each external network interface to the GGSM. Information about which of these external networks an individual customer is allowed access is contained in the HLR as an APN list in their profile.
ASCII	American Standard Code for Information Interchange. It is universally used as the prime means of converting characters to digital format.
Bandwidth	Bandwidth of a communications channel is a measure of the range of frequencies over which the carrier signal is allowed to vary. Generally a communications channel is defined by its lowest and highest frequency, and channel bandwidth is computed as the difference between the two as measured in Hertz, kHz or MHz. Since bandwidth of a channel is directly proportional to the amount of data that can be transmitted over it per unit time, channel bandwidth is sometimes measured as a data rate rather than as a frequency difference.
Bit	The smallest or basic unit in the digital representation of information, a bit can be thought of a binary digit taking the value of 1 or 0.
bps	Bits per second, a common measure of data transmission speed.
BG	Border gateway. The BG provides interconnection between GPRS networks across inter-PLMN backbones.
Broadband	A term used to describe a channel or communications line offering a bandwidth greater than 2Mb/s (may also be called Wideband).
BSC/BSS/BTS (Base Station Controller/Base Station System/Base Transceiver Station)	The heart of a cellular mobile phone system is a network of distributed transmitting/receiving radios in fixed locations called base transceiver stations (BTS). A base station controller or BSC is used to control groups of BTS, provide mobility management for mobile stations, anchor airlink protocols, and provide connection to an MCS or mobile switching center. The composite collection of one or more BTS and the associated BSC will form a BSS or Base Station Subsystem.
Byte	A Byte is a sequence of bits (usually 8) which represents a single character, such as a letter of the alphabet, a decimal digit, or a punctuation mark.
Carrier	A term loosely applied to any telecommunications operator providing voice and/or data services. Also used as a shortened form of "carrier signal".
Carrier Signal	A signal transmitted at a pre-determined frequency that carries voice or data. The carrier signal is modulated by voice or data input so as to "carry" the information to its destination where the modulation process is reversed to recover the original information.
CCBS	Customer Care and Billing System.
CDPD	Cellular Digital Packet Data is a data communications technology that uses Internet standard protocols to enable packet data services to be overlaid on an existing cellular network.
CDR	Originally CDR stood for 'call detail record', a call transaction record created by the MSC to track the network resources used by customers in making and receiving circuit switched calls, so that billing systems could compute charges based on resource usage (e.g., minutes on the air, etc.). Today the term is sometimes called a charging detail record, and generally applies to any transaction, traffic or resources usage records created by various other network components which may subsequently be used for billing purposes.
Cell	The geographic area served by a base station transceiver, or BTS, in a cellular network.
Cell Site	An alternative name for a base station transceiver or its site.
CG	Charging gateway. The CG collects, validates, and consolidates CDRs from other network components such as the SGSN and GGSN. It may then format the results for processing by the network billing system.
Circuit Switching	The process of establishing and maintaining a phone circuit or connection between two communications points so that the user has exclusive use of the communications path until the connection is released.
Circuit Switched Data (CSD)	Data communication over a dedicated channel or circuit assigned on a per call basis. CSD calls are often metered and priced by the minute like voice calls.
Decryption	This refers to the act of decoding encrypted information.
Dial-Up	Refers to the process of establishing a connection using the switched telephone network.
DNS (Domain Name System)	Domain name system. The DNS provides the location and translation of domain names into Internet Protocol addresses.
DNS Server	A DNS server holds translation tables linking domain names and APNs to IP addresses. It supplies the information to routers and other Internet elements on request.
Domain	An Internet domain consists of a set of network addresses organized into levels for purposes of identification, routing, and information delivery. The top level generally identifies a type of organization (e.g. ".com" for commercial, ".org" for non-commercial , and ".net" for communications network) or a geographic location, such as a country. The second level identifies a unique place within the top level grouping and is equivalent to a unique address on the Internet.
Downlink	Most data-communication connections are bi-directional. The direction toward the remote user is referred to as the "downlink." The direction away from the remote user is referred as the "uplink."
EDGE	Enhanced Data Rates for Global Evolution defines new signal modulation schemes that will permit much higher data rates to be achieved in GSM and TDMA networks. Rates up to 384 Kbps are expected which will enable the delivery of multimedia and other broadband applications to mobile phone and computer users.
Encryption	Refers to the act of altering data to make it unreadable unless you know how to decrypt it.
Error Detection & Correction	Refers to various techniques used to detect and correct errors that may be introduced when digital data is copied, moved, or transmitted to another device. Detection and correction technologies generally require that the data be expanded to include additional information. This can noticeably impact the rate at which the effective information is delivered.
Extranet	An extranet is an external extension of a company's intranet that allows limited, external access to defined portions of the intranet.
FDMA	Frequency Division Multiple Access is a technique used for dividing a band of radio frequencies into individual channels that can be assigned to calls over wireless networks. AMPS, GSM, and TDMA networks all rely on FDMA in varying degrees.
FEC	Forward Error Correction. FEC is a technique used in data communications for detecting and correcting transmission errors. FEC methods require that redundant information be added to help compensate for possible losses. It is most often used in situations where it is impractical to retransmit information damaged in transit.
Firewall	A firewall provides a security layer between one network and another. A firewall is situated between the GGSN and any external packet data networks connected to it. This provides a measure of protection for the GPRS network and its customers from hackers, spammers, or other unauthorized use.
Frequency	In communications, frequency represents the number of times a signal waveform repeats per second. Frequency is measured in Hertz (Hz).
Frequency Band	A frequency band is the continuous range of frequencies over which a signal waveform or carrier is allowed to vary.
Frequency Modulation (FM)	A technique for adding information to a carrier signal (e.g., a radio wave) whereby variations in the input are reflected by varying the frequency of the transmitted signal. This is the basis for FM radio.
Gateway	Usually a computer which controls communications within a network or between networks.
Ga, Gb, Gf, Gi, Gn, Gp, Gr, Gs	Each of these designates an interface between a particular pair of components in a GPRS network. For example, Gb denotes the interface between the SGSN and a Base Station Subsystem, or BSS. Such interfaces generally comprise hardware, software, protocols, and control mechanisms required to move GPRS traffic from point in the system to another.
G-CDR	A data traffic detail record created by the GGSN. It may be used for billing purposes.
GGSN (Gateway GPRS Support Node)	The GGSN provides the interconnection between the GPRS network and external packet data networks, much as the MSC interconnects a GSM voice services to the PSTN. Viewed externally, its primary function is that of an router.
GMSK (Gaussian Minimum Shift Keying)	The radio signal modulation technique used in GSM-based communications.
GPRS	General Packet Radio Service. GPRS is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network.
GSN (GPRS Support Node)	A general term referring the principal components of a GPRS network, e.g. GGSN and SGSN components.
GSM	The Global System for Mobile Communications Service, or GSM, is the most widely adopted, digital cellular technology in use today. GSM uses time and frequency division techniques (TDMA and FDMA) to optimize the call carrying capacity of a wireless network. In addition to voice services, GSM also provides a number of carefully standardized and broadly supported capabilities such as Short Message Service (SMS), circuit switched data (CSD) and General Packet Radio Services (GPRS).
GTP (GPRS Tunnelling Protocol)	IP packets traveling across the GPRS backbone (the data highway within the boundaries of a particular GPRS network) are enclosed in an additional protocol "wrapper" that contains information linking the destination IP address with the IMSI or mobile customer identifier (e.g. MIN). This is invisible in the Internet world but essential inside the GPRS network where dynamic IP assignments are used. The technique of adding a wrapper with additional routing information is called 'tunneling', and the particular protocol used for this purpose is the GTP or GPRS Tunneling Protocol.
Handset	Another term for cellular phones. Mobile phone, cellphone, and handset are used interchangeably.
Hertz or Hz	Hertz is a unit of measurement for the frequency of a cyclical waveform or repeating signal. It is equal to one cycle per second.
HLR	Home Location Register. A database that resides within a cellular network to hold current details about a customer, the equipment in use, the service(s) required, the user's identification encryption code, and the users "Home" cell, along with what network the customer was last known to be using .
HSCSD (High Speed Circuit Swiched Data)	A development of Circuit Switched Data, the original data transmission mechanism of the GSM mobile phone system. As with CSD, channel allocation is done in circuit switched mode. The difference comes from the ability to use different coding methods and multiple time slots to increase data throughput.
IMEI (International Mobile Equipment Identity)	A unique identification number associated with each GSM phone. In effect, a serial number that aids in tracking a particular device and is useful in fraud prevention. The IMEI is assigned by the manufacturer.
IMSI (International Mobile Subscriber Identity)	A unique identification number associated with a particular GSM customer. In effect a serial number that is essential to tracking the profile and location of a particular GSM customer, as well as making billing and service provisioning possible. It is assigned by the network operator and is carried in the SIM. More than one mobile number (MSISDN) may be associated with the same IMSI.
Internet	The Internet, or simply the Net, is the publicly accessible worldwide system of interconnected computer networks that transmit data by packet switching using a standardized Internet Protocol (IP), along with many other protocols. It is made up of thousands of smaller commercial, academic, domestic, and government networks. It hosts various services, such as electronic mail, online chat, and the interlinked Web pages and documents of the World Wide Web.
Intranet	An intranet is a local area network (LAN) used internally in an organisation to facilitate communication and access to information that is sometimes access-restricted. Sometimes the term refers only to the most visible service, the internal Web site. The same concepts and technologies of the Internet, such as clients and servers running on the Internet protocol suite, are used to build an intranet. HTTP and other Internet protocols are commonly used as well, especially FTP and e-mail.
IP (Internet Protocol)	The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet.
IP Address	The unique digital identifier of a device communicating over the Internet or other data network using similar technology. An IP address is similar to a postal address.
ISP	Internet Service Provider. An ISP provides Internet access, serving as an entry point to the world wide network. ISPs generally provide several means of access to their customers, including dial-up modem, DSL, Broadband, and ISDN.
IWF	The Interworking Function, sometimes called an Interworking Working Unit (IWU), is a wireless network component that enables communications between a computing device transmitting data over a wireless network and one normally accessible via dial-up modem over the public telephone network. The IWF provides a data bridge between a digital wireless network and the public telephone system.
IWU	Interworking Unit. The IWU provides a data bridge between a digital wireless network and the public telephone system.
LAN	Local Area Network. Inter-connected computers forming an internal network, or intranet. Used by businesses or organizations for sharing and managing information internally.
LIG (Lawful Interception Gateway)	Lawful interception gateways are used by designated security or law enforcement agencies to intercept GPRS traffic, similar to voice "wiretap" facilities in mobile networks. Legal authority to use this mechanism, as well as safeguards to protect privacy, will vary from country to country.
Kb	Kilobit is a term denoting 1024 bits.
KB	Kilobyte is a term denoting 1024 bytes, roughly equal to 8 kilobits.
Kbps	Kilobits per second describes the rate of transfer of data as measured in kilobits.
KHz	A unit of measurement for frequency equal to 1000 Hertz.
Mb	Megabit is a term denoting approximately one million bits. There is some argument as to whether a megabit should signify one million bits or 1, 048, 576 bits since the latter number more closely adheres to the binary arithmetic that lies at the heart of computer technology. On the other hand "mega" has long signified one million in the decimal system and is most widely understood in this way.
Mbps	Megabits per second. This is used for the rate of the transfer of data.
MHz	A unit of measurement for frequency equal to 1, 000, 000 Hertz.
Modem	A device which modulates (mo-) and demodulates (-dem) the signal carrier on a communications channel. When binary data (information as it is stored in a computer) is transmitted from one computer to another, modulation varies the carrier to represent the data during transmission, and demodulation interprets the variations of the signal so as to recapture the original information.
Modulation	A process by which information (e.g. voice, music, data) is added to a carrier signal. Three commonly used modulation techniques are Amplitude Modulation (AM), Frequency Modulation (FM), and Phase Modulation (PM).
MS (Mobile Station)	A mobile transceiver or mobile radio enabled device operating within a mobile network. Originally this term referred just to cell phones or handsets, but now includes mobile radio modems, or any device containing a mobile radio modem, as well.
MSC	Mobile switching center. The MSC provides basic telephone switching services to link a mobile or cellular network with the public telephone system or PSTN.
Multi-Band	Describes the facility of certain mobile stations to operate over two or more frequency bands, e.g., over some combination of the 800 MHz , 900MHz, 1800MHz, and 1900MHz bands commonly used by network operators. The selection of frequency band may be automatic or user-controlled. In the US, only the 800 MHz and 1900 MHz bands are used for cellular services. 900MHz service is found in Asia, and 1900 MHz service predominates in Europe.
Multi-Mode	Describes the facility of certain handsets to operate over more than one wireless technology, e.g., GSM, CDMA, TDMA, and AMPS. Dual mode AMPS/CDMA phones and AMPS/TDMA phones are still generally available from the original cellular network operators who continue to offer AMPS services in tandem with the newer digital network technologies.
Multiple Access	Multiple Access refers to techniques used in wireless telecommunication systems that permit sharing of limited radio frequency resources among a large numbers of potential users, not all of whom will require simultaneous access. The key assumption is that not all users will require simultaneous access. All the common wireless technologies, e.g. CDMA, FDMA, GSM, and TDMA, apply these techniques.
Netmask	A netmask specifies which part of an IP address specifies a specific host and which part designates the subnet to which the host belongs.
NAT (Network Address Translation)	The translation of an Internet Protocol address used within one network to a different IP address known within another network.
NSS (Network SubSystem)	The Network Switching Subsystem or NSS refers to that part of a GSM network primarily responsible for interconnection to the Public Service Telephone Network (PSTN). It collects charging information, maintains customer profiles, service information, wide area mobility management, etc. The principal components are the MSC, or switch, the Home Location Register (HLR), and the Visitor Location Register (VLR).
OSI (Open Systems Interconnection)	OSI is a standard description or "reference model" for how messages should be transmitted between any two points in a telecommunication network. Its purpose is to guide product implementers so that their products will consistently work with other products.
Packet	When data is transmitted over a network, it is divided into groupings of sequential bits called packets. Communications and error control information is added to the packet. At the data destination, the extra control information is removed and the original information is reconstructed from the individual packets.
PDP (Packet Data Protocol)	The primary protocol(s) used for packet data communications on a packet data network, e.g., TCP/IP on the Internet.
PDP Context	The PDP context is a data structure present on both the SGSN and the GGSN which contains the customer's session information, during an active session.
Packet Switching	A generic term for data communications techniques that move data from place to place in a network on an individual packet basis rather than by allocating a dedicated link. Packets can be routed independently so as to maximize network capacity.
PLMN (Public Land Mobile Network)	Today the term 'Public Land Mobile Network' refers to any wide area wireless or 'cellular' phone system. In the GSM world, inter-PLMN connections are generally restricted to other GSM networks providing similar services.
Port number	TCP and UDP provide an address mechanism, the port number, for identifying different applications communicating from the same IP address. Thus an active Web browser and an independently active mail program operating from the same IP location would typically use different port numbers. This way packets are correctly delivered to specific applications.
Protocol	Formal set of rules governing the format, timing, sequencing, and error control for data exchanges between two or more communications nodes.
Proxy	A component of a LAN, a proxy server acts as an intermediary between a workstation user and the Internet. This helps ensure security, administrative control, and caching service.
PSK (Phase Shift Keying)	Phase-shift keying (PSK) is a method for modulating a carrier signal by rapidly changing or shifting the signal wave phase as a method of sending information.
PSTN (Public Switched Telephone Network)	The PSTN refers to the world's collection of interconnected, voice-oriented public telephone networks.
"Push" Technology	A generic term applied to the methods, products, or services used to deliver information to an Internet user, without the user specifically requesting that item of information.
QAM (Quadrature Amplitude Modulation)	A modulation technique that uses variations in both signal amplitude and phase to convey information. This technique allows up to 128 data-encoded symbols to be represented per hertz (signal cycle).
RADIUS (Remote Authentication Dial-In User Service)	Radius refers to a client/server technique that enables remote access servers (RAS) to communicate with a central server (the Radius server) to authenticate dial-in users and authorize their access to the requested system or service.
RA (Routing Area)	For purposes of GPRS mobility management the concept of routing area has been added to the basic concepts of GSM. It can be thought of as an IP subnetwork and is always served by just one SGSN.
RAI (Routing Area Identifier)	Each routing area is assigned an identifier (RAI) by the network and is broadcast over the area by the network. A GPRS mobile station monitors the broadcast RAI, and when an RA border has been crossed, it must notify the network that it has moved to a new routing area.
RAS (Remote Access Server)	A remote access server handles users seeking access to network from a remote or outside location. It may provide gateway/bridge functions between the PSTN or Internet and an enterprise internal network. It also provides authentication services to prevent unauthorized parties from gaining access to the network it serves.
Routers	A router is a network resident computer that routes data traffic to and from other points on the network.
S-CDR	A data traffic detail record created by the SGSN which may subsequently be used for billing purposes.
SGSN (Serving GPRS Support Node)	The Serving GPRS support node, or SGSN, connects one or more BSCs to the GPRS backbone network, providing IP connectivity to the GGSN.
SIM Card (Subscriber Identity Module)	Subscriber Identity Module. The SIM card is a removable printed circuit and chip set card that holds information identifying the customer to the network. The most recent generation of SIMs are application programmable as well.
TCP	Transmission Control Protocol, or TCP, is used to provide reliable data transfer between two IP endpoints.
TCP/IP	Transmission Control Protocol (TCP) and Internet Protocol (IP) together define the basic rules for how information is transmitted across the Internet (and on most LANs) in packetized form.
TDMA	Time division multiple access is a communications technique where multiple users share a physical radio channel by being assigned specific, rotating time slots for transmitting and receiving.
TID (Tunnel ID)	Packets traveling along the GPRS backbone are wrapped inside an additional addressing layer to form GTP packets. Each GTP packet then carries a TID, or Tunneling identifier.
UDP (User Datagram Protocol)	User Datagram Protocol is used to provide fast data transfer between two IP end points, but it is not as reliable a method as TCP.
Uplink	Most data-communication connections are bi-directional. The direction away from the remote user is referred as the "uplink." The direction toward the remote user is referred to as the "downlink."
URL	Universal Resource Locator. A URL is the Internet address of an HTML, HTM, WAV, or other file. Every document available on the Internet must have a unique address.
VPN (Virtual Private Network)	A virtual private network (VPN) is a private data network that makes use of the public telecommunication infrastructure, maintaining privacy through the use of a tunneling protocol and security procedures.