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89 terms

chapter 7

STUDY
PLAY
asymmetrical
Characteristic of a transmission technology that affords greater bandwidth in one direction than in the other directions
asymmetrical DSL
A variation of DSL that offers more throughput when data travels downstream, than when it travels upstream
Asynchronous
a communications method in which nodes do not have to conform to any predetermined schemes that specify the timing of data transmissions
Asynchronous Transfer Mode
A data link layer technology originally conceived in the early 1980s at Bell Labs and standardized by the ITU in the mid-1990s. Relies on fixed packets, that consist of 48 bytes of data plus a 5 byte header
authentication
The server compares credentials with those in its database
B channel
the "bearer" channel, employing circuit-switching techniques to carry voice, video, audio, and other types of data over the ISDN connection
Basic rate interface
uses two B channels and one D channel
bonding
the process of combining more than one bearer channel of an ISDN line to increase throughput
broadband cable
A method of connecting to the Internet over a cable network
bus topology WAN
A WAN in which each site is directly connected to no more than two other sites in a serial fashion
cable drop
The fiber-optic or coaxial cable that connects a neighborhood cable node to a customer's house
cable modem
a device that modulates and demodulates signals for transmission and reception via cable wiring
cell
A packet of a fixed size
central office
the place where a telephone company terminates lines and switches calls between different locations
Channel service unit
a device that provides termination for the digital signal and ensures connection integrity through error correction and line monitoring
Channel service unit/Data Service unit
the connection point for a T1 line at the customers site
committed information rate
A minimum amount of bandwidth that the service provider guarantees
credentials
a user name and password
D channel
the "data" channel, employing packet-switching techniques to carry information about the call, such as session initiation and termination signals, caller identity, and call forwarding, and conference calling signals
Data Service unit
a device that converts the T-carrier frames into frames the LAN can interpret and vice versa
dedicated lines
continuously available communications channels from a telecommunications provider, such as a local telephone company or ISP
dial up
connection in which a user connects her computer, via a modem, to a distant network and stays connected for a finite period of time
Dial up networking
The process of dialing into a remote access server to connect with a network
digital signal, level 0
equivalent of one data or voice channel
digital subscriber line
A dedicated WAN technology that uses advanced data modulation techniques at the Physical Layer to achieve extraordinary throughput over regular phone lines
downstream
refers to data traveling from the carrier's switching facility to the customer
DSL access multiplexer
a device that aggregates multiple DSL subscriber lines and connects them to the carriers CO
DSL modem
a device that demodulates incoming DSL signal, extracting the information and passing it to the data equipment and modulates outgoing DSL signals
E1
A digital carrier standard used in Europe that offers 30 channels and a maximum of 2.048 Mbps
E3
A digital carrier standard used in Europe that offers 480 channels and a maximum of 34.368 Mbps
fiber to the home
a carriers provision of fiber-optic connections to residential end users for dramatically increased throughput and a better range of services
fractional T1
allows organizations to use only some of the channels on a T1 line and be charged according to the number of channels they use
frame relay
An updated, digital version of X.25 that also relies on packet switching
full mesh WAN
The type of mesh topology in which every WAN site is directly connected to every other site
head end
a cable company's central office, which connects cable wiring to many nodes before it reaches customer sites
hybrid fiber-coax
a link that consists of fiber cable connecting the cable company's offices to a node location near the customer and coaxial cable connecting the node to the customer's house
Independent Computing Architecture client
The software from Citrix Systems INC, that when installed on a client, enables the client to connect with a host computer and exchange keystrokes, mouse clicks, and screen updates.
Integrated Services Digital Network
an international standard, originally established by the ITU in 1984, for transmitting digital data over the PSTN
J1
A digital carrier standard used in Japan that offers 24 channels and 1.544 Mbps
J3
A digital carrier standard used in Japan that offers 480 channels and 32.064 Mbps
Layer 2 Tunneling Protocol
A protocol that encapsulates PPP data, for use on VPNs.
LAN Emulation
encapsulates incoming Ethernet or token ring frames, then converts them into ATM cells for transmission over an ATM network
local loop
the portion of the PSTN that connects any residence or business to the nearest CO
mesh topology WAN
every site is interconnected, data can travel directly from its origin to its destination
network interface unit
the point at which PSTN-owned lines terminate at a customers premises
network service providers
A carrier that provides long-distance connectivity between major data-switching centers across the Internet
Network Termination 1
device that connects the twisted pair wiring at the customer's building with the ISDN terminal equipment via RJ-11 or RJ-45
Network Termination 2
an additional connection device required on PRI To handle the multiple ISDN lines between the customer's network termination connection and the local phone company's wires
open source
the term for software that is developed and packaged by individuals and made available to anyone for free
Optical Carrier
a rating that is internationally recognized by networking professionals and standards organizations
partial mesh WAN
type of mesh topology in which only critical WAN sites are directly interconnected and secondary sites are connected through star or ring topologies
permanent virtual circuits
a point to point connection over which data may follow any number of different paths, as opposed to a dedicated line that follows a predifned path
plain old telephone service
another name for Public switched telephone network
Point to Point protocol
a communications protocol that enables a workstation to connect to a server using a serial connection
PPP over Ethernet
PPP running over an Ethernet network
Primary Rate Interface
uses 23 B channels and one 64-Kbps D channel
Public Switched Telephone Network
the network of lines and carrier equipment that provides telephone service to most homes and businesses
Remote Access Service
The dial-up networking software provided with Microsoft Windows client operating sytems.
Remote Access
a method for connecting and logging on to a LAN from a workstation that is remote, or not physically connected, to the LAN
Remote Desktop
a feature of Windows operating systems that allows a computer to act as a remote host and be controlled from a client running another Windows OS
Remote Desktop Protocol
an Application layer protocol that uses TCP/IP to transmit graphics and text quickly
ring topology WAN
each site is connected to two other sites so that the entire WAN forms a ring pattern
Routing and Remote Access Service
Microsofts software that enables a server to act as a router, firewall, and remote access server
self-healing
A characteristic of dual-ring topologies that allows them to automatically reroute traffic along the backup ring if the primary ring becomes severed
Serial Line Internet Protocol
A communications protocol that enables a workstation to connect to a server using a serial connection
signal level
An ANSI standard for T-carrier technology that refers to its Physical layer electrical signaling characteristics
smart jack
A termination for T-carrier wire pairs that is located at the customer demark and which functions as a connection protection and a monitoring point
star topology WAN
A single site acts as the central connection point for several other points
switched virtual circuits
a logical, point to point connection that relies on switches to determine the optimal path between sender and receiver
symmetrical
provides equal capacity for data traveling both upstream and downstream
symmetrical DSL
a variation of DSL that provides equal throughput both upstream and downstream between the customer and the carrier
Synchronous Digital Hierarchy
the international equivalent of SONET
Synchronous optical network
a high-bandwidth WAN signaling technique developed by Bell Communications Research in 1980s, and later standardized by ANSI and ITU. It specifies framing and multiplexing techniques at the physical layer.
Synchronous
data being transmitted and received by nodes must conform to a timing scheme.
T1
carry the equivalent of 24 voice or data channels, giving a maximum data throughput of 1.544 Mbps
T3
carry the equivalent of 672 voice or data channels, giving a maximum data throughput of 44.736 Mbps
T-carrier
the term for any kind of leased line that follows the standards for T1s, fractional T1s, T1Cs, T2s, T3s, or T4s
terminal adapter
device that converts digital signals into analog signals for use with ISDN phones and other analog devices
terminal equipment
the end nodes served by the same connection
tiered topology WAN
sites connected in star or ring formations are interconnected at different levels, with the interconnection points being organized into layers to form hierarchical groupings
tunnel
a secured, virtual connection between two nodes on a VPN
tunneling
the process of encapsulating one type of protocol in another
Upstream
refers to data traveling from the customer to the carrier's switching facility
Virtual circuits
connections between network nodes that, although based on potentially disparate physical links, logically appear to be direct, dedicated links between those nodes
virtual network computing
an open source system designed to allows one workstation to remotely manipulate and receive screen updates from another workstation
virtual private networks
a logically constructed WAN that uses existing public transmission systems
WAN link
a point to point connection between two nodes on a WAN
X.25
an analog, packet-switched technology designed for long-distance data transmission and standardized by the ITU in the mid-1970s
xDSL
the term used to refer to all varieties of DSL