Decibels isotropic. A relative gain measurement with respect to an isotropic radiator in free space (uniform emitter in free space, a theoretical situation). It usually describes gain for antennas operating at 1 GHz or above.
dBm
Decibels milliwatt. Decibels referred to a reference level of 1 milliwatt (mW). dBM is a measure of power in communications: the decibel in reference to one milliwatt.
decibels
A measurement method used to simplify the expression and calculation of wireless power levels. It is also the unit used for measuring antenna gain. Decibels are abbreviated as dB, and you may also see dBm and dBi.
demilitarized zone
See DMZ.
DES
Data Encryption Standard. DES is a well-established symmetric key encryption algorithm standardized by ANSI in 1981 as ANSI X.3.92. It was originally defined by the National Institute of Standards and Technology.
DHCP
Dynamic Host Configuration Protocol. A standard network protocol that dynamically assigns IP addresses, and other settings, to clients, usually from a centralized DHCP server.
Direct-Sequence Spread-Spectrum
See DSSS.
DMZ
Demilitarized zone. Takes its name from the neutral ground between two opposing parties. A DMZ separates trusted and untrusted networks.
DNS
Domain Name System. The method by which Internet domain names are validated and translated into IP addresses. The scheme uses a distributed set of DNS servers. Enterprises can also create and operate their own DNS servers within their own networks.
DSSS
Direct-Sequence Spread-Spectrum. DSSS generates spread-spectrum transmissions, which are transmitted concurrentlythat is, over two or more frequencies. This technique increases the signal's resistance to interference. DSSS is one of two types of spread-spectrum radio technology used in WLAN transmissions, the other being FHSS.
