CHAPTER 23
DATA-LINK PROTOCOLS AND DATA
COMMUNICATIONS NETWORKS
1)The
primary goal of __________ is to give users of a network the tools necessary
for setting up the network and performing data flow control.
Network Architecture
2)A set of
rules implementing and governing an orderly exchange of data between two layer
devices.
Data-Link Protocol
3)The
transmitting station in a data link protocol.
Master Station
4)The
receiving station in a data link protocol.
Slave Station
5)Data link
network wherein all stations have equal access to the network.
Peer-to Peer Network
6)Discipline,
Flow Control and Error Control.
Functions of Data-link Protocol
7)Coordinates
hop-to-hop data delivery where a hop may be a computer, a network controller,
or some type of network-connecting device
Line Discipline
8)Determines
which device is transmitting and which is receiving at any point in time.
Line Discipline
9)Coordinates
the rate which data are transported over a link and generally provides an acknowledgement
mechanism.
Flow Control
10)Specifies
means of detecting and correcting transmission errors.
Error Control
11)Two
fundamental ways that line discipline is accomplished in a data communications
network.
Enquiry/Acknowledgement(ENQ/ACK) and Poll/Select
12)It
determines which device on the network can initiate a transmission and whether
the intended receiver is available and ready to receive a message.
ENQ/ACK
13)The
initiating station begins a session by transmitting a frame, block, or packet
of data called _________, which identifies the receiving station.
Enquiry(ENQ)
14)The
response of the destination station when it is ready to receive.
Positive Acknowledgement (ACK)
15)The
response of the destination station when it is not ready to receive.
Negative Acknowledgement (NAK)
16)The
best application of the poll/select line discipline.
Centrally Controlled Data Network
17)A
solicitation sent from the primary to a secondary to determine if the
secondary
has data to transmit
Poll
21)A set
of procedures that tells the transmitting station how much data it can send
before it must stop transmitting and wait for an acknowledgment from the
destination station
Flow Control
22)The
transmitting station sends one message frame and then waits for an
acknowledgement before sending the next message frame.
Stop-and Wait Flow Control
23)A
source station can transmit several frames in succession before receiving an
acknowledgement.
Sliding Window Flow Control
24)It
refers to imaginary receptacles at the source and destination stations with the
capacity of holding several frames of data.
Sliding Window
25)Primary
advantage of sliding window control.
Network Utilization
26)Primary
disadvantages of sliding window flow control.
Complexity and Hardware Capacity
27)Interpret
a frame of data as a group of successive bits combined into predefined patterns
of fixed length, usually eight bits each.
Character Oriented Protocols
28)Another
name for character oriented protocols.
Byte-oriented Protocols
29)A
discipline for serial by bit information transfer over a data communications
channel.
Bit Oriented Protocol
30)A
character-oriented protocols generally used on two point networks using
asynchronous data and asynchronous modems.
Asynchronous Data link Protocols
31)Developed
the first file transfer protocol designed to facilitate transferring data
between two personal computers in 1979.
Ward Christiansen
32)Cristiansen's
protocol which is relatively simple data link protocol intended for low-speed
applications.
XMODEM
33)Remote
stations can have more than one PC or printer.
Synchronous Data-Link Protocols
34)A group
of computers, printers, and other digital devices.
Cluster
35)A
synchronous character-oriented data link protocol developed by IBM.
Binary Synchronous Communications (BSC)
36)Another
name for BSC.
Bisync
37)Another
name for enquiry (ENQ) character.
Format or line turn around
38)The
__________ uses longitudinal redundancy checking (LRC) with ASCII-coded
messages and cyclic redundancy checking.
Block Check Character (BCC)
39)A
synchronous bit oriented protocol developed in the 1970's by IBM for use in
system network architecture environment.
Synchronous Data-Link Control (SDLC)
40)Three
transmission states.
Transient, Idle and Active
41)Flag
Fields, Address Field, Control Field, Information and Frame Check Sequence
Field are __________.
SDLC Frame Fields
42)It is
used for the delimiting sequence for the frame and to achieve frame and
character synchronization.
Flags
43)It is
used for polling, confirming previously received frames, and several other data
link management functions
Control Field
44)Three
frame formats with SDLC.
Information, Supervisory and Unnumbered
45)A
command or a response that is used to send unnumbered information.
Unnumbered Information (UI)
46)A
command that places a secondary station into the initialization mode.
Set Initialization Mode
47)A
response sent by a secondary station to request the primary to send a SIM
command.
Request Initialization Mode (RIM)
48)A
command that places a secondary into the normal response mode.
Set Normal Response Mode (SNRM)
49)A
response transmitted from a secondary station if the primary attempts to send
numbered information frames to it when the secondary is in the normal
disconnect mode.
Disconnect Mode (DM)
50)A
response sent by a secondary when it wants the primary to place it in the
disconnect mode.
Request Disconnect (RD)
52)An
affirmative response that indicates compliance to SIM, SNRM or DISC commands
Unnumbered Acknowledgement
53)An
exchange of frames between the primary station and a secondary station.
TEST
54)A flag
followed by eight consecutive logic 0's.
Turnaround Sequence
55)A SDLC
subcommand causes all previously set functions to be cleared by the secondary.
Clear
56)A SLDC
subcommand causes the secondary receiving it to turn on or turn off its
carrier.
Beacon Test
57)A SDLC
command causes the addressed secondary station to pace itself into the monitor
mode.
Monitor Mode
58)A SDLC
command causes a secondary station to loop its transmission directly to its
receiver input.
Wrap
59)A SDLC
command causes the addressed secondary to initiate a series of internal
diagnostic tests.
Self-Test
60)The
transparency mechanism used with SDLC.
Zero Bit Insertion or Zero Stuffing
61)It is
used prematurely terminate an SDLC frame.
Message Abort
62)The
encoding scheme used in SDLC.
Invert-On-Zero Coding
63)Standard
that defines the frame structure, delimiting sequence, transparency mechanism
and error detection method used with HDLC.
ISO 3309
64)Operational
Mode of SDLC.
Normal Response Mode (NRM)
65)A mode
of operation logically equivalent to a two point private line circuit where
each station has equal data link responsibilities.
Asynchronous Balanced Mode
66)A
switched data communications network similar to the public telephone network
except a PDN is designed for transferring data only.
Public Switched Data Network (PDN)
67)It is
used when making a standard telephone call on the public telephone network.
Circuit Switching
68)Is a
form of store and forward network.
Message Switching
69)Another
name for packet switching.
Hold and Forward Network
70)A user
interface as the international standard for packet network access.
X.25
71)SA
logically equivalent to a two point dedicated private line circuit except
slower.
Permanent Virtual Circuit (PVC)
72)A
logically equivalent to making a telephone call through the DDD network except
no direct end to end connection is made.
Virtual Call
73)Identifies
whether the packet is a new call request or a previously established call.
Format Identifier
74)A 12
bit binary number that identifies the source and destination users for a given
virtual call.
Logical Channel Identifier
75)This
four bit gives the number of digits that appear in the calling address filed.
Calling Address Field
76)This
field is the same as the calling address field except that it identifies the
number of digits that appear in the called address field
Called Address Length
77)This
field contains the destination address.
Called Address
78)This
field is the same as the called address field except that it contains up to 15
BCD.
Calling Address
79)This
field identifies the number of eight bit octets present in the facilities
field.
Facilities Length Field
80)This 32
bit field is reserved for the subscriber to insert user level protocol.
Protocol Identifier
81)A
proposed network designed by the major telephone companies in conjunction with
the ITU-T.
Integrated Services Digital Network (ISDN)
82)Customers
gain access to the ISDN system through a local interface connected to a digital
transmission medium.
Digital Pipe
83)ISDN
objectives that ensure universal access to the network.
System Standardization
84)Said
objectives that allow customers to use a variety of protocols and applications
Achieving
Transparency
85)ISDN
should not provide services that preclude competitiveness
Separating Functions
86)Provide
private-line and switched services refers what objectives of ISDN.
Variety of Configurations
87)ISDN
services should not be directly related to cost and independent of the nature
of the data.
Addressing Cost-Related Tariffs
88)Provide
a smooth transition while evolving.
Migration
89)Provide
service to low capacity personal subscribers as well as to large companies.
Multiplexed Support
90)Translation
between non-ISDN data protocol and ISDN is performed in this device.
Terminal Adapter
91)A
boundary to the network and may be controlled by the ISDN provider.
Network Termination 1
92)Refers
to interfaces between the common carrier subscriber loop and the central office
switch
U-Reference Point
93)The
media interface point between an NT1 and the central office.
U Loop
94)It is
defined by ITU-T as a service that provides transmission channels capable of
supporting transmission rates greater than the primary data rate.
Broadband ISDN
95)Information
transfer is primarily from service provider to subscriber
Distribution Services
96)Codes
the data information into smaller packets used by the BISDN network
Broadband Node
97)A
connection between a source and a destination, which may entail several ATM
links.
Virtual Channel
98)Once
data have entered the ATM network, they transferred into fixed time slots
called ________.
Cells
99)Controls
the flow of traffic across the user network interface (UNI) and into the
network.
Generic Flow Control Field (GFC)
100)The
first three bits of the second half of byte 4 specify the type of message in
cell.
Payload Type Identifier
101)Information
fields that are designed to accommodate PCM-TDM traffic, which allows the ATM
network to emulate voice or DSN services.
Constant Bit Rate
102)A
portion of a public service provider's switching system where the service
provider could be a local telephone company or a long-distance carrier.
Public ATM Switches
103)Provides
the most effective and economical means of handling local data communications
field.
Local Area Networks (LAN)
104)A
communications system that allows users to send messages to each other through
their computers.
E-Mails
105)LAN
Topologies.
Star, Bus and Ring Topology
106)It
describes how users access the communications channel in a LAN.
Network Access Methodologies
107)Access
method used primarily in bus topology.
CDMA/CD
108)It two
stations transmit at the same time, ________ occurs.
Collision
109)The
time it takes a signal to travel from a source to a destination.
Propagation Delay
110)A base
band transmission system designed in 1972 by Robert Metcalfe and David Boggs.
Ethernet
111)Its
purpose is to establish clock synchronization.
Preamble
112)It is
simply a series of two logic 1's appended to the end of the preamble.
Start Frame Delimiter
113)Consists
of six bytes the corresponds to the address of the station sending the frame.
Source Address
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