The speed at which 802.11 radios exchange symbols, which is always higher than the available throughput. For example, the nominal data rate of 802.11g is
54 Mbps, while the maximum throughput is about 20 Mbps). See also: throughput
A logarithmic unit of measurement that expresses the magnitude of power relative to a reference level. Commonly used units are dBi (decibels relative to an
isotropic radiator) and dBm (decibels relative to a milliwatt).
When a router receives a packet destined for a network for which it has no explicit route, the packet is forwarded to the default gateway. The default gateway
then repeats the process, possibly sending the packet to its own default gateway, until the packet reaches its ultimate destination.
Denial of Service (DoS)
An attack on network resources, usually achieved by flooding a network with traffic or exploiting a bug in an application or network protocol.
When two identical waves merge and are exactly out of phase, the amplitude of the resulting wave is zero. This is called destructive interference. See
also: constructive interference
The simplest form of omnidirectional antenna.
An antenna that radiates very strongly in a particular direction. Examples of directional antennas include the yagi, dish, and waveguide antennas.
The ability of an antenna to focus energy in a particular direction when transmitting, or to receive energy from a particular direction when receiving.
Domain Name Service (DNS)
The widely used network protocol that maps IP addresses to names.
Dynamic Host Configuration Protocol (DHCP)
A protocol used by hosts to automatically determine their IP address.