616 Glossary
320657-A
digital signature The result of encrypting a hash of a message or document with a private key. A digital
signature is used to verify the authenticity of the sender and the integrity (unaltered condition) of the message
or document. See also hash.
Digital Signature Algorithm See DSA.
direct-sequence spread-spectrum See DSSS.
domain (1) On the Internet, a set of network addresses that are organized in levels. (2) In Microsoft
Windows NT and Windows 2000, a set of network resources (applications, printers, and so forth) for a group
of users (clients). Clients log into the domain to access the resources, which can be located on a number of
different servers in the network.
domain policy A collection of configuration settings that you can define once in WLAN Management
Software and apply to many WLAN—Security Switch (WSS) switches. Each Mobility Domain group in the
network has a default domain policy that applies to every WSS switch in the Mobility Domain. See also Policy
Manager.
DSA Digital Signature Algorithm. The public-key algorithm used to sign X.509 certificates.
DSSS Direct-sequence spread-spectrum. One of two types of spread-spectrum radio technology used in
wireless LAN (WLAN) transmissions. To increase a data signal’s resistance to interference, the signal at the
sending station is combined with a higher-rate bit sequence that spreads the user data in frequency by a factor
equal to the spreading ratio. Compare FHSS.
DTIM Delivery traffic indication map. A special type of traffic indication map (TIM) element in a beacon
frame that occurs only when a station in a basic service set (BSS) is in power-save mode. A DTIM indicates
that any buffered broadcast or multicast frames are immediately transmitted by an access point (AP).
DXF format A tagged data representation, in ASCII format, of the information contained in an AutoCAD
drawing file.
dual-homed connection A redundant, resilient connection between an Access Point (AP) and one
or more Wireless Security Switch (WSS) switches. The connection can consist of two direct physical links
from both AP ports to one or two WSS switches, one or more distributed links through an intermediate Layer
2 or Layer 3 network, or a combination of one direct physical link and one or more distributed links. The AP
uses one link for booting, configuration, and data transfer and uses the other link(s) as backups in case the
active link fails. If the AP has two direct physical links to one or more WSSs , the Power over Ethernet (PoE)
load is shared across both links. If the active data link fails, the other link provides uninterrupted power to the
AP access port.
After changing its active link, the access point reboots and loads new configuration information to ensure proper config-
uration and security. Mobility Domain services are temporarily disrupted by the link change. Dual-homed connections
are not required but are recommended. See also bias.
EAP Extensible Authentication Protocol. A general point-to-point protocol that supports multiple
authentication mechanisms. Defined in RFC 2284, EAP has been adopted by IEEE 802.1X in an encapsulated
form for carrying authentication messages in a standard message exchange between a user (client) and an
authenticator. The encapsulated EAP, also known as EAP over LAN (EAPoL) and EAP over Wireless
(EAPoW), enables the authenticator’s server to authenticate the client with an authentication protocol agreed
upon by both parties. See also EAP type.
