0-9  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z gallium arsenide (GaAs) A semiconductor material used in high-frequency telecommunications components. gateway Entrance or exit to a communications network of any size. Technically, a gateway is an electronic repeater device that intercepts and steers electrical signals from one network to another. general packet switched radio system (GPRS) A 2.5G technology that will enable faster data transmission for wireless data subscribers on GSM networks. GPRS theoretically delivers data transmission rates of 90-150 kbps and is being tested now in Europe and Asia. generalized multiprotocol label switching (GMPLS) An evolved version of MPLS with generalized switching requirements and additional functions such as bi-directional LSP establishment, generalized notification mechanism, and ingress/egress binding. generally accepted accounting principles (GAAP)   giga- A prefix for one billion (109) times a specific unit. gigabit ethernet (Gig-E) Gigabit ethernet is a local area network (LAN) transmission standard used in the enterprise backbone that provides a data rate of 1 billion bits per second (one gigabit). Ethernet networks operated at Gbps speeds, allowing for higher bandwidth transmission in LAN or LAN analog networks. gigabit interface converter (GBIC) A removable serial transceiver module designed to provide gigabit capability for Fibre Channel (FC) and other protocols that use the same physical layer. gigabits per second (Gbps) One billion bits per second. A measure of transmission speed. gigahertz (GHz) A frequency of a billion cycles per second. global positioning system (GPS) A system used in cellular phones, laptops, and luxury cars which can locate a unit anywhere on the globe to within a few meters. The system uses a network of 24 satellites and was first launched by the U.S. Department of Defense. global system for mobile communications (GSM) Originally meaning Groupe Speciale Mobile, GSM is a standard digital cellular phone service used in Europe, Japan, and Australia. As of mid-1999, GSM networks were operational in 133 countries. There are four types of GSM: 450 Mhz (Scandanvia), 900 Mhz (the original flavor everywhere outside of North America and South America), 1800 Mhz (a new flavor everywhere outside of North America and much of South America), and 1900 Mhz (North America and South America). GSM networks enable wireless subscribers to use a SIM (subscriber identity module) card that is inserted into the phone and carries the consumer's identification data. This card can be removed and inserted into another phone from another carrier, giving wireless consumers the ability to port their information and number to another carrier. goodwill In an acquisition, under the purchase method of accounting, goodwill appears on the balance sheet of the acquirer in the amount by which the purchase price exceeds the net tangible assets of the acquired company. Goodwill is an intangible asset that represents the acquirer's view on the competitive advantage of the target company, such as a strong brand name, well-developed customer relationships, or good employee morale. Since it is intangible, generally accepted accounting principles (GAAP) require that goodwill be written off, usually calculated straight-line over a period of 15-years. Technology companies may have a significant amount of goodwill, since factors such as the ability to have built a strong brand and employee retention are valuable to the success of the company. graded-index fiber An optical fiber the core of which has a non-uniform index of refraction. The core is composed of concentric rings of glass with refractive indexes that decrease with distance from the center axis. The purpose of using this fiber is to reduce modal dispersion and thereby increase bandwidth. gratings Term referring to devices that filter-separate light into its constituent wavelength. There are multiple grating technologies, including diffraction gratings, transmission gratings, arrayed waveguide gratings, and fiber Bragg gratings. In optical networking systems, these devices are used in a variety of applications such as multiplede multiplexingexing, add/drop, and dispersion compensation greenfield Essentially the opposite of "legacy." A greenfield network is one that is being designed and built from scratch, with no need to accommodate legacy (i.e., old) equipment or architectures. Usage extends to almost any aspect of describing a new venture. green shoe Shares allocated to underwriters in an initial or a secondary offering to satisfy excess demand. The over-allotment is exercised at the sole discretion of the lead underwriter. grooming The managing of bandwidth on a wide-area, public or private network to use the long-haul transmission facilities as effectively as possible. gross margin Gross margin is the profitability of a company's sales before operating expenses, and is expressed as a percentage. Calculated by dividing gross profit by net revenues to obtain gross profit as a percentage of revenues.