LAN: Chapter 7: Vocab Flashcards
adaptive differential pulse code modulation (ADPCM)
An audio file creation technique that converts an analog audio signal into an 8-bit digital signal, similar to regular pulse code modulation (PCM), but it transmits voice communications at less than half or one fourth the speed of regular PCM communications.
Asymmetric Digital Subscriber Line (ADSL)
A high-speed digital subscriber line technology that can use ordinary telephone lines for downstream data transmission of up to 6 Mbps, and 576-640 Kbps for upstream transmissions.
Basic Rate Interface (BRI) ISDN
An ISDN interface that consists of three channels. two are 64-Kbps channels for data, voice, and video transmissions. A third is a 16-Kbps channel used for communications signaling.
broadband ISDN (B-ISDN)
Currently under development and not widely implemented, this technology provides a data transfer rate of 155 Mbps and higher.
Challenge Handshake Authentication Protocol (CHAP)
A protocol used to encrypt passwords, such as server account passwords that are transferred over a WAN.
circuit mode
On an ISDN network that uses T-carrier communications, this means the communications circuit lasts for the duration of the communications session and is used exclusively by the two connected devices until it is terminated.
Compressed Serial Line Internet Protocol (CSLIP)
An extension of the SLIP remote communications protocol that provides faster throughput than SLIP.
data circuit equipment (DCE)
On an X.25 network, a packet switch or access device to a PDN.
datagram
An X.25 transmission mode that does not use a particular communications channel, which often results in data arriving in a different order than it was sent, because each datagram may follow a different route to the destination.
data link connection identifier (DLCI)
Identifies an individual virtual connection on a frame relay network.
data terminal equipment (DTE)
On an X.25 network, terminals, workstations, servers, and host computers that operate on a packet-switching network. DTE devices are sometimes called terminals, regardless of the actual device that is used.
digital subscriber line (DSL or xDSL)
A technology that uses advanced modulation technologies on existing telecommunications networks for high-speed networking between a subscriber and a telco, and that has communication speeds up to 55 Mbps.
Distributed Queue Dual Bus (DQDB)
An SMDS interface that consists of two shared fiber-optic media. Both fiber-optic cables are attached to the customer premises equipment at one end, and to the vendor switch at the other.
echo cancellation
Used in ISDN, this communications method transmits data on the line in two directions at the same time. The two-way simultaneous transmissions often cause reflections (echos) of the transmitted signal. ISDN uses an echo canceler to overcome the reflected signals.
frame relay
A communications protocol that relies on packet switching and virtual connection technology to transmit data packets, and that achieves higher transmission rates by leaving extensive error-checking functions to intermediate nodes.
frame relay assembler/disassembler (FRAD)
Also called a frame relay access device, specialized equipment often in the form of a module (card) in a switch or router that converts packets from the local network (LAN) into a format that can be transmitted over a frame relay network, and vice versa.
G.lite Asymmetic Digital Subscriber Line (G.lite ADSL)
A Plug and Play compatible version of ADSL that transmits at 500 Kbps upstream and 1.5 Mbps downstream.
High Bit-Rate Digital Subscriber Line (HDSL)
A form of high-speed digital subscriber line technology that has fixed upstream and downstream transmission rates of either 1.544 or 2.3 Mbps.
Integrated Services Digital Network (ISDN)
A standard for delivering data services over telephone lines, with a current practical limit of 1.536 Mbps and a theoretical limit of 622 Mbps.
Integrated Services Digital Network Digital Subscriber Line (IDSL)
A DSL version that is compatible with a Digital Loop Carrier device that may be used on some telephone networks. IDSL provides upstream and downstream communications at 144 Kbps.
Link Access Procedure-Balanced (LAPB) protocol
Employed in x.25 communications, a protocol that is used to set up and discontinue virtual connections over the WAN.
Link Access Procedure D channel (LAPD)
Also referred to as the Q.921 protocol, specifies the frame format for ISDN Layer 2 communications.