超星 - 自测题 ch3

单选题

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.

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单选题

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

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单选题

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

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单选题

_____ 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

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单选题

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

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单选题

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

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单选题

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

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单选题

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

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单选题

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

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单选题

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. 42
C. 109
D. 110

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