USRobotics Instant802 APSDK manual Dcf, Dhcp, Dns, Dom, Dtim

Professional Access Point

Administrator Guide

D

DCF

The Distribution Control Function is a component of the IEEE 802.11e Quality of Service (QoS) technology standard. The DCF coordinates channel access among multiple stations on a wireless network by controlling wait times for channel access. Wait times are determined by a random backoff timer which is configurable by defining minimum and maximum contention windows. See also EDCF.

DHCP

The Dynamic Host Configuration Protocol (DHCP) is a protocol specifying how a central server can dynamically provide network configuration information to clients. A DHCP server offers a lease (for a pre- configured period of time—see Lease Time) to the client system. The information supplied includes the client's IP addresses and netmask plus the address of its DNS servers and Gateway.

DNS

The Domain Name Service (DNS) is a general-purpose query service used for translating fully-qualified names into Internet addresses. A fully-qualified name consists of the hostname of a system plus its domain name. For example, www is the host name of a Web server and www.usr.com is the fully-qualified name of that server. DNS translates the domain name www.usr.com to an IP address, for example 66.93.138.219.

A domain name identifies one or more IP addresses. Conversely, an IP address may map to more than one domain name.

A domain name has a suffix that indicates which top level domain (TLD) it belongs to. Every country has its own top-level domain, for example .de for Germany, .fr for France, .jp for Japan, .tw for Taiwan, .uk for the United Kingdom, .us for the U.S.A., and so on. There are also .com for commercial bodies, .edu for educational institutions, .net for network operators, and .org for other organizations as well as .gov for the U. S. government and .mil for its armed services.

DOM

The Document Object Model (DOM) is an interface that allows programs and scripts to dynamically access and update the content, structure, and style of documents. The DOM allows you to model the objects in an HTML or XML document (text, links, , tables), defining the attributes of each object and how they can be manipulated.

Further details about the DOM can be found at the W3C.

DTIM

The Delivery Traffic Information Map (DTIM) message is an element included in some Beacon frames. It indicates which stations, currently sleeping in low-power mode, have data buffered on the Access Point awaiting pick-up. Part of the DTIM message indicates how frequently stations must check for buffered data.

Dynamic IP Address

See IP Address.

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