immune to attacks in Software

Make Code-39 in Software immune to attacks

cyclic redundancy check (CRC) A highly accurate error-detection method based on interpreting a pattern of bits as a polynomial

data element The smallest entity that can represent a piece of information A bit data encryption standard (DES) The US government standard encryption method for

data link control The responsibilities of the data link layer: flow control and error control data link layer The second layer in the Internet model It is responsible for node-to-node delivery Data Over Cable System Interface Specifications (DOCSIS)

data rate The number of data elements sent in one second data transfer phase The intermediate phase in circuit-switched or virtual-circuit network in

datagram In packet switching, an independent data unit datagram network A packet-switched network in which packets are independent from each

A protocol that has not been approved by an organized body but adopted as a standard through widespread use

de jure standard A protocol that has been legislated by an officially recognized body deadlock A situation in which a task cannot proceed because it is waiting for an even that will

decibel (dB)

decryption Recovery of the original message from the encrypted data default mask The mask for a network that is not subnetted default routing A routing method in which a router is assigned to receive all packets with no match in the routing table Defense Advanced Research Projects Agency (DARPA) A government organization,

demodulation The process of separating the carrier signal from the information-bearing signal demultiplexer (DEMUX) A device that separates a multiplexed signal into its original

dense wave-division multiplexing (DWDM)

A WDM method that can multiplex a very large number of channels by spacing channels closer together

transition at the middle of the bit interval as well as an inversion at the beginning of each 1 bit

Differentiated Services (DS or Diffserv) A class-based QoS model designed for IF Diffie-Hellman protocol A key management protocol that provides a one-time session key

digest A condensed version of a document digital AMPS (D-AMPS) A second-generation cellular phone system that is a digital version

Data represented by discrete values or conditions A digital version of an analog leased line with a rate of 64 Kbps A telephone company service featuring a hierarchy of digital A discrete signal with a limited number of values

digital subscriber line (DSL) A technology using existing telecommunication networks to accomplish high-speed delivery of data, voice, video, and multimedia digital subscriber line access multiplexer (DSLAM) that functions like an ADSL modem digital-to-analog conversion digital-to-digital conversion digitization Dijkstra's algorithm routers direct current (DC) A telephone company site device

The representation of digital information by an analog signal The representation of digital information by a digital signal

Conversion of analog information to digital information In link state routing, an algorithm that finds the shortest path to other A zero-frequency signal with a constant amplitude

direct delivery A delivery in which the final destination of the packet is a host connected to c the same physical network as the sender direct sequence spread spectrum (DSSS) A wireless transmission method in which each bit to be sent by the sender is replaced by a sequence of bits called a chip code discard eligibility (DE) congestion in the network A bit that identifies a packet that can be discarded if there is

discrete cosine transform (DCT) A JPEG phase in which a transformation changes the 64 values so that the relative relationships between pixels are kept but the redundancies are revealed discrete multitone technique (DMT) andFDM A modulation method combining elements of QAM

Distance Vector Multicast Routing Protocol (DVMRP) A protocol based on distance vector routing that handles multicast routing in conjunction with IGMP distance vector routing A routing method in which each router sends its neighbors a list of networks it can reach and the distance to that network distortion Any change in a signal due to noise, attenuation, or other influences distributed coordination function (DCF) The basic access method in wireless LANs; stations contend with each other to get access to the channel distributed database Information stored in many locations