Ch 8 Terms - WANs Flashcards
X.25
An analog packet-switched WAN technology optimized for reliable long-distance transmission at a maximum of 2 Mbps.
ISDN
An international standard that uses PSTN lines to carry digital signals–often voice and data signals simultaneously.
OC
An internationally recognized rating that indicates throughput rates for SONET connections.
NSP
AT&T, Verizon, and Sprint are all examples of this type of provider.
BPL
High-speed Internet access delivered over the electrical grid.
ONU
In a passive optical network, the device near the customer’s premises that terminates a carrier’s fiber-optic cable connection and distributes signals to multiple endpoints via fiber-optic cable (FTTP).
ATM
Relies on fixed packets, called cells, that each consists of 48 bytes of data plus a 5-byte header.
CSU/DSU
The connection point for a T1 line at the customer’s site, often with a multiplexer.
CIR
The guaranteed minimum amount of bandwidth selected when leasing a frame relay circuit.
PTSN
The network of lines and carrier equipment that provides telephone service to most homes and businesses (POTS).
NIU
The point at which PSTN-owned lines terminate at a customer’s premises, usually located at the demarc.
DSLAM
A connectivity device located at a telecommunications carrier’s office that aggregates multiple digital subscriber lines and connects them to a larger carrier or to the Internet backbone.
DSL
A dedicated WAN technology that uses advanced data modulation techniques to achieve extraordinary throughput over regular phone lines.
OLT
A device located at the carrier’s endpoint of a passive optical network.
E1
A digital carrier standard used in Europe that offers 30 channels and a maximum of 2.048 Mbps throughput.
E3
A digital carrier standard used in Europe that offers 480 channels and a maximum of 34.368 Mbps throughput.
T1
A digital carrier standard used in North America and most of Asia that provides 1.544 Mbps throughput and 24 channels for voice, data, video, or audio signals. Uses TDM over twisted pair, coax, or fiber.
T3
A digital carrier standard used in North America and most of Asia that provides 44.736 Mbps throughput and 672 channels for voice, data, video, or audio signals. Uses TDM over fiber.
FRAME RELAY
A digital packet-switched WAN technology which offers throughputs between 64 Kbps and 45 Mbps.
SONET
A high-bandwidth WAN signaling technique that specifies framing and multiplexing techniques.
PRI
A type of ISDN that uses 23 bearer channels and one 64 Kbps data channel, represented by the notation 23B+D.
BRI
A variety of ISDN that uses two 64 Kbps bearer channels and one 16 Kbps data channel (2B+D).
