chapter 4 (2) Flashcards
What is the primary function of the “Message Delineation” function in the Data Link Layer?
a) Determining the speed of data transmission
b) Identifying where a message starts and stops
c) Controlling the flow of data within the network
d) Deciding the priority of different types of messages
B
____________ is not a function of a data link protocol.
a. Media access control
b. Message delineation
c. Amplitude shift keying
d. Indicating when a message starts and stops
e. Error control
C
Which of the following functions does the Data Link Layer perform?
a) Adds a Protocol Data Unit (PDU) called a packet to the received frame.
b) Adds a Protocol Data Unit (PDU) called a frame to the received packet from the network layer.
c) Adds a Protocol Data Unit (PDU) called a segment to the received packet from the transport layer.
d) Adds a Protocol Data Unit (PDU) called a segment to the received frame.
B
What is the primary purpose of the frame added by the Data Link Layer to the received packet?
a) Enhancing network performance
b) Ensuring message delineation and error control
c) Increasing data transfer speed
d) Enabling end-to-end communication
B. This frame includes necessary information for message delineation and error control.
Asynchronous transmission:
a. is used to transmit each character simultaneously with all other characters
b. has a pre-determined, fixed time between sending characters
c. is typically used on multipoint half duplex circuits
d. uses a continuous series of start bits as an idle signal
e. is also known as start-stop transmission
E
Asynchronous transmission:
a. is used to transmit each character simultaneously with all other characters
b. has a pre-determined, fixed time between sending characters
c. is typically used on multipoint half duplex circuits
d. uses a continuous series of start bits as an idle signal
e. each character is transmitted independently of all other characters
E
Which of the following is an example of a protocol that uses asynchronous transmission?
a) HTTP
b) FTP
c) VT100
d) TCP
C
How many bits are typically used for the transmission of each character in asynchronous transmission with 7-bit ASCII and even parity?
a) 7 bits
b) 8 bits
c) 9 bits
d) 10 bits
D
In asynchronous transmission, what signal is sent down the circuit when no data is being transmitted?
a) Start bit
b) Stop bit
c) Idle signal
d) Parity bit
C
What does the start bit indicate in asynchronous transmission?
a) End of character
b) Start of character
c) Data transmission complete
d) Data error detected
B
Which type of circuit is asynchronous transmission typically used on?
a) Point-to-point half-duplex circuits
b) Point-to-point full-duplex circuits
c) Multi-point half-duplex circuits
d) Multi-point full-duplex circuits
B. media access control is not a concern
How is the idle signal defined in asynchronous transmission?
a) Same as the start bit
b) Same as the stop bit
B
Which protocols have traditionally used asynchronous transmission?
a) HTTP and FTP
b) TCP/IP and UDP
c) VT100 and Telnet
d) SSH and SSL
C
Which of the following is not a type of synchronous protocol?
a. SDLC
b. VT100
c. HDLC
d. Ethernet
e. PPP
B
Synchronous transmission:
a. cannot be used on multipoint circuits
b. is used to send one character at a time
c. uses start bits before each character to be sent
d. uses stop bits after each character to be sent
e. is used to transmit a “frame” or “packet” of data at a time
E
How are data typically sent in synchronous transmission?
a) Independently of each other
b) In small packets
c) In a large block called a frame
d) Through continuous streams
C
What is included in a frame in synchronous transmission?
a) Only data bits
b) Only media access control information
c) Addressing information and media access control
d) Only synchronization characters
C
What purpose do synchronization (SYN) characters serve in synchronous transmission?
a) To indicate the end of a frame
b) To identify the receiver
c) To help the receiver recognize the beginning of a frame
d) To encrypt the data being transmitted
C
How many SYN characters can be present at the start of a frame in synchronous transmission?
a) One
b) Four
c) Six
d) Eight
D
Approximately how many bits can a frame contain in synchronous transmission?
a) Hundreds
b) Thousands
c) Tens
d) Millions
B
In which type of circuit is synchronous transmission typically needed?
a) Point-to-point circuits
b) Multipoint circuits
c) Wireless circuits
d) Analog circuits
B
Which of the following is true about the data link protocol, SDLC:
a. It is a client-server protocol developed by Compaq in 1996
b. It is a byte-count-oriented protocol
c. It uses a special bit pattern called a flag at the beginning and end of every frame (or
packet)
d. It uses a contention media access control protocol
e. It does not have a problem with transparency
C
Synchronous transmission cannot be used on multipoint circuits.
F
Who developed the Synchronous Data Link Control (SDLC) protocol?
a) Apple Inc.
b) IBM
c) Microsoft Corporation
d) Google
B
Which type of Media Access Control (MAC) does SDLC utilize?
a) Random access MAC
b) Controlled access MAC
c) Carrier Sense Multiple Access/Collision Detection (CSMA/CD)
d) Time Division Multiple Access (TDMA)
B
If you use a 3270 protocol, you’re using SDLC.” This statement is:
a) True
b) False
T
What marks the beginning and end of a typical SDLC frame?
a) Start and stop bits
b) Special bit pattern known as the flag (01111110)
c) Synchronization characters
d) Header and footer fields
B
What is the typical length of the address field in an SDLC frame?
a) 16 bits
b) 8 bits
c) 32 bits
d) 64 bits
B.The address field identifies the destination. The length of the address field
is usually 8 bits but can be set at 16 bits
What is the purpose of the control field in an SDLC frame?
a) Identifying the destination address
b) Indicating the beginning and end of the frame
c) Specifying the frame type being transmitted
d) Verifying the integrity of the message field
C. The control field identified frame type being transmitted:
Information frames: For transferring of user message
Supervisory frames: for acknowledgments (ACKs) and negative acknowledgments (NAKs).
What type of frames are used in SDLC for acknowledgments and negative acknowledgments?
a) Information frames
b) Error frames
c) Supervisory frames
d) Control frames
C
What is the primary purpose of acknowledgments (ACKs) and negative acknowledgments (NAKs) in SDLC?
a) Encrypting the user’s message
b) Indicating the start and end of a frame
c) Error correction and retransmission
d) Specifying the destination address
C
What type of frames are used in SDLC for transferring user messages?
a) Control frames
b) Supervisory frames
c) Information frames
d) Error frames
C
What type of information is typically contained in the message field of an SDLC frame?
a) Routing information
b) Synchronization data
c) The user’s message
d) Error detection codes
C. Variable in lengths
What does the frame check sequence field in an SDLC frame contain?
a) Address of the sender
b) User’s message
c) 32-bit CRC code
d) Start and stop bits
C. (some older versions use a 16-bit CRC).
HDLC is very similar to the SDLC synchronous data link protocol.
T
________ has essentially replaced SDLC. It offers a larger sliding window.
a. Ethernet
b. PPP
c. Asynchronous transmission
d. HDLC
e. Full complex
D
Which organization developed HDLC (High-Level Data Link Control) as a formal standard?
a) IBM
b) IEEE
c) ISO
d) IETF
C
What type of Media Access Control (MAC) does HDLC utilize?
a) Random access MAC
b) Controlled access MAC
c) Carrier Sense Multiple Access/Collision Detection (CSMA/CD)
d) Time Division Multiple Access (TDMA)
B
How does HDLC differ from SDLC in terms of address and control fields?
a) HDLC has shorter address and control fields
b) HDLC has longer address and control fields
c) HDLC does not use address and control fields
d) HDLC and SDLC have identical address and control fields
B
What characteristic of HDLC distinguishes it from SDLC in terms of Automatic Repeat Request (ARQ)?
a) Smaller sliding window size
b) Larger sliding window size
c) Absence of sliding window size
d) Identical sliding window size
B