Data and Computer Communications, 10th Edition, by William Stallings
Chapter 15: transport protocols
TRUE OR FALSE
T F 1. A transport protocol can be either connection oriented, such as
UDP, or connectionless, such as TCP.
T F 2. The receiver needs to adopt some policy concerning the amount of
data it permits the sender to transmit.
T F 3. There is no need for connection establishment and termination
procedures to support connection-oriented service with a reliable
network service.
T F 4. When a TCP entity detects the presence of congestion in the
Internet, it reduces the flow of data onto the Internet until it
detects an easing in congestion.
T F 5. The SYN segment functions both as a connection request and as a
connection acknowledgment.
T F 6. In a protocol architecture, the transport protocol sits above
application and other upper-layer protocols, and just below the
network or internetwork layer.
T F 7. The less the network service provides, the more the transport
protocol must do.
T F 8. If there is a single host-node link over which all virtual circuits are
multiplexed, the throughput of a transport connection can exceed
the data rate of that link.
T F 9. The sliding-window technique would work well with a reliable
network service.
T F 10. An internetwork using IP is an example of a reliable network
service.
T F 11. A credit scheme is a more effective scheme with an unreliable
network service.
T F 12. A retransmission timer is the only timer needed for proper
functioning of a transport protocol.
T F 13. A problem with a two-way handshake is the potential loss of
segments and the potential presence of obsolete segments.
T F 14. As with IP, the services provided by TCP are defined in terms of
primitives and parameters.
T F 15. The credit-based flow control mechanism of TCP was designed to
enable a destination to restrict the flow of segments from a source
to avoid buffer overflow at the destination.
MULTIPLE CHOICE
1. TCP uses a ______flow control technique.
A) sliding-window B) upper-layer
C) sequential D) credit-based
2. The ______variable represents a particular TS user at the specified host.
A) Port B) Host
C) Socket D) Transport
3. All of the following are ways of the receiving transport entity to cope with the flow control requirement EXCEPT:
A) use a credit scheme
B) do nothing
C) use a fixed sliding-window protocol
D) accept further segments from the network service
4. To begin a connection establishment a TS user is in a ______state.
A) CLOSED B) LISTEN
C) OPEN D) ESTAB
5. Multiple users employing the same transport protocol and distinguished by port numbers or service access points is ______.
A) multiplexing B) sequencing
C) flowing D) full duplex
6. "Abort connection when no segments are received" is the ______Transport Protocol Timer.
A) 2MSL B) Keepalive
C) Retransmission D) Persist
7. In the case of a single network, ______refers to an attached network device.
A) Port B) Host
C) Socket D) Entity
8. Once the Passive Open command is issued, the transport entity creates a connection object of some sort that is in the ______state.
A) OPEN B) LISTEN
C) CLOSED D) FIN
9. Connection establishment in TCP always uses a ______.
A) four-way handshake B) three-way handshake
C) two-way handshake D) handshake
10. ______provides a means of informing the destination TCP user that significant data is in the upcoming data stream. It is up to the destination user to determine appropriate action.
A) Data stream signaling B) Attention signaling
C) Urgent data signaling D) Alert signaling
11. One header must serve to perform all protocol mechanisms. This header has
a minimum length of ______octets.
A) 20 B) 16
C) 8 D) 10
12. The TCP header ______field contains the number of data octets, beginning
with the sequence number indicated in the acknowledgment field, that the
sender is willing to accept.
A) Window B) Checksum
C) Options D) Acknowledgment Number
13. When a data segment arrives that is in sequence, the receiving TCP entity
has two options concerning the timing of acknowledgment: Immediate and
______.
A) Cumulative B) Controlled
C) Delayed D) Non-responsive
14. Using ______, a sender retransmits a segment before timeout because it infers that the segment was lost. If the sender subsequently receives an acknowledgement that does not cover all of the segments transmitted before this is initiated, the sender may infer that two segments were lost from the current window and retransmit an additional segment.
A) fast retransmit B) backoff
C) outward data dissemination D) Karn's Algorithm
15. “Listen for connection attempt at specified security and precedence from specified destination" is the description of the TCP Service Request ______Primitive.
A) Generally Specified Passive Open
B) Unspecified Passive Open
C) Active Open With Data
D) Fully Specified Passive Open
SHORT ANSWER
1. The ______protocol provides an end-to-end transfer service that shields upper-
layer protocols from the details of the intervening network or networks.
2. A ______service provides for the establishment, maintenance, and termination of
a logical connection between TS users. To date this is the most common type of
protocol service available and has a wide variety of applications.
3. In TCP the combination of port and host is referred to as a ______.
4. In addition to data each transmitted segment includes in its header three fields
related to flow control: acknowledgment number, window, and ______.
5. The TS user can signal to the local TCP entity that it will passively wait for a
request with a ______command. A server program such as time-sharing or a file
transfer application might do this.
6. A ______timer is reset with each outgoing segment. If this timer ever expires the
protocol entity is required to send a segment, even if it duplicates a previous one.
7. When the system upon which a transport entity is running fails and subsequently
restarts, the state information of all active connections is lost. The affected
connections become ______because the side that did not fail does not yet realize
the problem.
8. ______measures the time the transport machine will continue to await an
acknowledgment of a transmitted segment after the segment has been
retransmitted the maximum number of times. When the timer expires, the
transport entity assumes that the other transport entity or intervening network
has failed, closes the connection, and signals an abnormal close to the TS user.
9. The two facilities that TCP provides for labeling data are push and ______.
10. TCP uses only a single type of protocol data unit called a ______.
11. The ______field in the TCP header contains the sequence number of the next
data octet that the TCP entity expects to receive.
12. TCP mechanisms can be grouped into the categories of data transfer, connection
termination, and ______.
13. A TCP implementation may employ one of three retransmission strategies:
First-only, Individual, and ______.
14. RTT Variance Estimation, also known as ______, is the technique specified in the
TCP standard that enables a TCP entity to adapt to changes in round-trip time.
15. In addition to TCP, the ______is the other transport-level protocol that is
commonly used as part of the TCP/IP protocol suite.