A data received from application above B de-multiplexing segment
C timer timeout D ACK receipt
85. Which of the following applications normally uses UDP services? A SMTP
B Streaming multimedia C FTP D HTTP
86. Which of the following about TCP connection is not correct? A It is a broadcast connection B It is a point-to-point connection C It is a pipelined connection D It is a full duplex connection
87. The SYN segment is used for____. A TCP connection setup B TCP flow control
C TCP congestion control D Closing a TCP connection
88. Which service helps prevent the internet from entering a state of gridlock? A reliable data transfer B flow control
C congestion control D handshaking procedure
89. The Internet’s _____is responsible for moving packets from one host to another. A application layer B transport layer
C network layer D link layer
90. In the following applications, which one is a bandwidth-sensitive application? A E-mail
B web application C real-time audio D file transfer
91. In the following applications, which one uses UDP? A E-mail
B web application C file transfer D DNS
92. In the following four descriptions, which one is correct?
A If one host’s transport layer uses TCP, then its network layer must use virtual-circuit network.
B Datagram network provides connection service
C The transport-layer connection service is implemented in the router
D The network-layer connection service is implemented in the router as well as in the end system.
93. ____ is a speeding-matching service---matching the rate which the sender is sending against the rate at which the receiving application is reading. A congestion control B flow control
C sliding-window control D variable control
94. In the following four descriptions about Rcv-Window, which one is correct?
A The size of the TCP RcvWindow never changes throughout the duration of the connection
B The size of the TCP RcvWindow will change with the size of the TCP RcvBuffer C The size of the TCP RcvWindow must be less than or equal to the size of the TCP RcvBuffer
D Suppose host A sends a file to host B over a TCP connection, the number of unacknowledged bytes that A sends cannot exceed the size of the size of the RcvWindow.
95. There are 6 flag fields. Which one is to indicate that the receiver should pass the data to the upper layer immediately? A PSH B URG C ACK D RST
96. Suppose the TCP receiver receives the segment that partially or completely fills in gap in received data, it will ____.
A immediately send ACK B immediately send duplicate ACK
C wait some time for arrival of another in-order segment D send single cumulative
97. _____ imposes constrain on the rate at which a TCP sender can send traffic into the network.
A sliding window B congestion window
C receive window D variable window
98. Flow control and congestion control are same at that they all limit the rate of the sender, but differ in that ____.
A flow control limits its rate by the size of RcvWindow, but congestion control by the traffic on the link
B congestion control limits its rate by the size of RcvWindow, but flow control by the traffic on the link
C flow control mainly is accomplished by the sender, but congestion control by the receiver.
D flow control mainly is accomplished by the receiver, but congestion control by
the link.
99. This job of delivering the data in a transport-layer segment to the correct socket is called ____.
A multiplexing B de-multiplexing C forwarding D routing
100. If we define N to be the window size, base to be the sequence number of the oldest unacknowledged packet, and next-seq-num to be the smallest unused sequence number, then the interval [base, nextseqnum-1] corresponds to packet that ____. A can be sent immediately
B have already been transmitted and acknowledged C cannot be used
D have been sent but not yet acknowledged
101. ____ are the two types of transport services that the Internet provides to the applications.
A TCP and UDP
B connection-oriented and connectionless service C TCP and IP
D reliable data transfer and flow control
102. In the following descriptions about persistent connection, which one is not correct?
A The server leaves the TCP connection open after sending a response B Each TCP connection is closed after the server sending one object
C There are two versions of persistent connection: without pipelining and with pipelining
D The default mode of HTTP uses persistent connection with pipelining 103. The field of Length in UDP segment specifies the length of ____. A the UDP segment, not including the header B the UDP segment, including the header C the UDP segment’s header D the Length field
104. In TCP segment header, which field can implement the reliable data transfer? A source port number and destination port number B sequence number and ACK number
C urgent data pointer D Receive window
105. In the following four descriptions about TCP connection management, which one is not correct?
A Either of the two processes participating in a TCP connection can end the connection
B If the FIN bit is set to 1, it means that it wants to close the connection
C In the first two step of the three-way handshake, the client and server randomly choose an initial sequence number
D In the three segments of the three-way handshake, the SYN bit must be set to 1 106. Suppose host A sends two TCP segments back to back to host B over a TCP connection. The first segment has sequence number 42, and the second has sequence number 110. If the 1st is lost and 2nd arrives at host B. What will be the acknowledgment number?
A 43 B ACK42 C 109 D ACK110
1. Consider sending an object of size O=500,000bytes from server to client. Let S=500 bytes and RTT=0.2s. Suppose the transport protocol uses static windows with window size 5. For a transmission rate of 100Kbps, determine the latency for sending the whole object. Recall the number of windows K=O/ WS), and there is K-1 stalled state (that is idle time gaps).
2.Consider the following plot of TCP congestion window size as a function of time.
16 Fill in the blanks as follow:
a) The initial value of Threshold at the first transmission round is ____. b) The value of Threshold at the 11st transmission round is ____. c) The value of Threshold at the 21st transmission round is ____. d) After the 9th transmission round, segment loss detected by ____.
(A) Timeout
(B) Triple duplicate ACK
e) After the 19th transmission round, segment loss detected by ____.
(A) Timeout
(B) Triple duplicate ACK
f) During ____ transmission round, the 18th segment is sent.
3.Consider the TCP reliable data transfer in the given graph. If in Segment 1’s Sequence number =10,data=“AC”, please fill in the following blanks. a) In Segment 2, ACK number=____;
b) In Segment 3, Sequence number =____; data=“0123456789”
c) If there are some bits corrupted in segment 3 when it arrives Host B, then the ACK number in Segment 5 is ____; and the ACK number in Segment 6 is ____. Congestion window size 12 8 4 0 2 4 6 8 10 12 14 16 1820 22 2426 28 3032 0 0 0
Transmission round