CISCO CERTIFIED TECHNICIAN
EXAM QUESTIONS AND VERIFIED
ANSWERS (LATEST UPDATE
Atm (asynchronous transfer mode)
The interna5onal standard for cell relay in which mul5ple service types (such as
voice, video, or data) are conveyed in fixed-length (53-byte) cells. Fixed-length
cells allow cell processing to occur in hardware, thereby reducing transit delays.
Atm is designed to take advantage of high-speed transmission media, such as
e3, sonet, and t3.
Bandwidth
The difference between the highest and lowest frequencies available for
network signals. The term also is used to describe the rated throughput
capacity of a given network medium or protocol. The frequency range
necessary to convey a signal measured in units of hertz (hz). For example, voice
signals typically require approximately 7 khz of bandwidth and data traffic
typically requires approximately 50 khz of bandwidth.
Bri (basic rate interface)
Basic rate interface. Isdn interface composed of two b channels and one d
channel for circuit-switched communica5on of voice, video, and data.
Broadcast
Data packet that are sent to all nodes on a network. Broadcasts are iden5fied
by a broadcast address.
Cd (carrier detect)
A signal that indicates whether an interface is ac5ve. Also, a signal generated
by a modem indica5ng that a call has been connected.
Cdp (cisco discovery protocol)
,Media- and protocol-independent device-discovery protocol that runs on all
cisco-manufactured equipment, including routers, access servers, bridges, and
switches. Using cdp, a device can adver5se its existence to other devices and
receive informa5on about other devices on the same lan or on the remote side
of awan. Runs on all media that support snap, including lans, frame relay, and
atm media.
Central office (co)
The local telephone company office to which all local loops in a given area
connect and in which circuit switching of subscriber lines occurs.
Channel service unit (csu)
Digital interface device that connects end-user equipment to the local digital
telephone loop. OSen referred to together with dsu, as csu/dsu.
Checksum
Method for checking the integrity of transmiUed data. A checksum is an integer
value computed from a sequence of octets taken through a series of arithme5c
opera5ons. The value is recomputed at the receiving end and is compared for
verifica5on.
Collision domain
In ethernet, the network area within which frames that have collided are
propagated. Repeaters and hubs propagate collisions; lan switches, bridges,
and routers do not.
Common language equipment iden5fier (clei)
The standard code used by suppliers to iden5fy equipment parts and system
configura5ons. Its a registered trademark of bellcore (now telcordia).
Customer premises equipment (cpe)
Termina5ng equipment, such as terminals, telephones, and modems, supplied
by the telephone company, installed at customer sites, and connected to the
,telephone company network. Can also refer to any telephone equipment
residing on the customer site.
Cyclic redundancy check (crc)
Error-checking technique in which the frame recipient calculates a remainder
by dividing frame contents by a prime binary divisor and compares the
calculated remainder to a value stored in the frame by the sending node.
Data communica5ons equipment (dce)
Devices and connec5ons of a communica5ons network that comprise the
network end of the user-to-network interface. It provides a physical connec5on
to the network, forwards traffic, and provides a clocking signal used to
synchronize data transmission between dce and dte devices. Modems and
interface cards are examples.
Data service unit (dsu)
Device used in digital transmission that adapts the physical interface on a dte
device to a transmission facility, such as t1 or e1. The dsu also is responsible for
such func5ons as signal 5ming. OSen referred to together with csu, as csu/dsu.
Data terminal equipment (dte)
Device at the user end of a user-network interface that serves as a data source,
des5na5on, or both. Dte connects to a data network through a dce device (for
example, a modem) and typically uses clocking signals generated by the dce.
Dte includes such devices as computers, protocol translators, and mul5plexers.
Echo
Telephony-audible and unwanted leak-through of one's own voice into one's
own receive (return) path. Hence signal from the transmission path is returning
to one's ear through the receive path.
Encapsula5on
, Wrapping of data in a par5cular protocol header. For example, ethernet data is
wrapped in a specific ethernet header before network transit. Also, when
bridging dissimilar networks, the en5re frame from one network is simply
placed in the header used by the data link layer protocol of the other network.
End system
Nonrou5ng host or node in an osi network.
Endpoint
H.323 terminal or gateway. An endpoint can call and be called. It generates and
terminates the informa5on stream.
Ethernet
Baseband lan specifica5on invented by xerox corpora5on and developed jointly
by xerox, intel, and digital equipment corpora5on. Ethernet networks use
csma/cd and run over a variety of cable types at 10 mbps. Ethernet is similar to
the ieee 802.3 series of standards.
Frame
Logical grouping of informa5on sent as a data link layer unit over a
transmission medium. OSen refers to the header and the trailer, used for
synchroniza5on and error control, that surround the user data contained in the
unit. The terms cell, datagram, message, packet, and segment also are used to
describe logical informa5on groupings at various layers of the osi reference
model and in various technology circles.
Frame check sequence (fcs)
Extra characters added to a frame for error control purposes. Used in hdlc,
frame relay, and other data link layer protocols.
Gateway
In the ip community, an older term referring to a rou5ng device. Today, the
term router is used to describe nodes that perform this func5on, and gateway
EXAM QUESTIONS AND VERIFIED
ANSWERS (LATEST UPDATE
Atm (asynchronous transfer mode)
The interna5onal standard for cell relay in which mul5ple service types (such as
voice, video, or data) are conveyed in fixed-length (53-byte) cells. Fixed-length
cells allow cell processing to occur in hardware, thereby reducing transit delays.
Atm is designed to take advantage of high-speed transmission media, such as
e3, sonet, and t3.
Bandwidth
The difference between the highest and lowest frequencies available for
network signals. The term also is used to describe the rated throughput
capacity of a given network medium or protocol. The frequency range
necessary to convey a signal measured in units of hertz (hz). For example, voice
signals typically require approximately 7 khz of bandwidth and data traffic
typically requires approximately 50 khz of bandwidth.
Bri (basic rate interface)
Basic rate interface. Isdn interface composed of two b channels and one d
channel for circuit-switched communica5on of voice, video, and data.
Broadcast
Data packet that are sent to all nodes on a network. Broadcasts are iden5fied
by a broadcast address.
Cd (carrier detect)
A signal that indicates whether an interface is ac5ve. Also, a signal generated
by a modem indica5ng that a call has been connected.
Cdp (cisco discovery protocol)
,Media- and protocol-independent device-discovery protocol that runs on all
cisco-manufactured equipment, including routers, access servers, bridges, and
switches. Using cdp, a device can adver5se its existence to other devices and
receive informa5on about other devices on the same lan or on the remote side
of awan. Runs on all media that support snap, including lans, frame relay, and
atm media.
Central office (co)
The local telephone company office to which all local loops in a given area
connect and in which circuit switching of subscriber lines occurs.
Channel service unit (csu)
Digital interface device that connects end-user equipment to the local digital
telephone loop. OSen referred to together with dsu, as csu/dsu.
Checksum
Method for checking the integrity of transmiUed data. A checksum is an integer
value computed from a sequence of octets taken through a series of arithme5c
opera5ons. The value is recomputed at the receiving end and is compared for
verifica5on.
Collision domain
In ethernet, the network area within which frames that have collided are
propagated. Repeaters and hubs propagate collisions; lan switches, bridges,
and routers do not.
Common language equipment iden5fier (clei)
The standard code used by suppliers to iden5fy equipment parts and system
configura5ons. Its a registered trademark of bellcore (now telcordia).
Customer premises equipment (cpe)
Termina5ng equipment, such as terminals, telephones, and modems, supplied
by the telephone company, installed at customer sites, and connected to the
,telephone company network. Can also refer to any telephone equipment
residing on the customer site.
Cyclic redundancy check (crc)
Error-checking technique in which the frame recipient calculates a remainder
by dividing frame contents by a prime binary divisor and compares the
calculated remainder to a value stored in the frame by the sending node.
Data communica5ons equipment (dce)
Devices and connec5ons of a communica5ons network that comprise the
network end of the user-to-network interface. It provides a physical connec5on
to the network, forwards traffic, and provides a clocking signal used to
synchronize data transmission between dce and dte devices. Modems and
interface cards are examples.
Data service unit (dsu)
Device used in digital transmission that adapts the physical interface on a dte
device to a transmission facility, such as t1 or e1. The dsu also is responsible for
such func5ons as signal 5ming. OSen referred to together with csu, as csu/dsu.
Data terminal equipment (dte)
Device at the user end of a user-network interface that serves as a data source,
des5na5on, or both. Dte connects to a data network through a dce device (for
example, a modem) and typically uses clocking signals generated by the dce.
Dte includes such devices as computers, protocol translators, and mul5plexers.
Echo
Telephony-audible and unwanted leak-through of one's own voice into one's
own receive (return) path. Hence signal from the transmission path is returning
to one's ear through the receive path.
Encapsula5on
, Wrapping of data in a par5cular protocol header. For example, ethernet data is
wrapped in a specific ethernet header before network transit. Also, when
bridging dissimilar networks, the en5re frame from one network is simply
placed in the header used by the data link layer protocol of the other network.
End system
Nonrou5ng host or node in an osi network.
Endpoint
H.323 terminal or gateway. An endpoint can call and be called. It generates and
terminates the informa5on stream.
Ethernet
Baseband lan specifica5on invented by xerox corpora5on and developed jointly
by xerox, intel, and digital equipment corpora5on. Ethernet networks use
csma/cd and run over a variety of cable types at 10 mbps. Ethernet is similar to
the ieee 802.3 series of standards.
Frame
Logical grouping of informa5on sent as a data link layer unit over a
transmission medium. OSen refers to the header and the trailer, used for
synchroniza5on and error control, that surround the user data contained in the
unit. The terms cell, datagram, message, packet, and segment also are used to
describe logical informa5on groupings at various layers of the osi reference
model and in various technology circles.
Frame check sequence (fcs)
Extra characters added to a frame for error control purposes. Used in hdlc,
frame relay, and other data link layer protocols.
Gateway
In the ip community, an older term referring to a rou5ng device. Today, the
term router is used to describe nodes that perform this func5on, and gateway
