Self-Assessment Quizzes Chapter 3 MC,T&F

Consider the latency model for dynamic congestion windows. Which of the following components contribute to latency

all of the above

round trip time, RTT

the transmission time of the object, O/R

the sum of all the stalled times

When a TCP segment arrives to a host, the socket to which the segment is directed depends on

the destination port number

the source IP address of the datagram that encapsulated the segment

the source port number

all of the above

UDP has which of the following characteristics:

regulated send rate

three-way hand shake for connection establishment

connection state at the server

none of the above

When a UDP segment arrives to a host, in order to direct the segment to the appropriate socket, the OS uses

the source port number

the destination port number

the source IP address

all of the above

The stop-and-wait protocol is highly inefficient when

when there is a short distance between source and destination and the transmission rate is large

when there is a short distance between source and destination and the transmission rate is low

when there is a large distance between source and destination and the transmission rate is high

when there is a large distance between source and destination and the transmission rate is low

Pipelining requires which of the following

unique sequence numbers for each in-transit packet

transmitting many packets before receiving acknowledgements

sender-side buffering of unacknowledged packets

all of the above

TCP applies fast retransmit to a segment when

the segment's timer expires

none of the above

when it receives three ACKs for an earlier segment

it estimates unusually large RTTs

Nmap is often used to:

Measure round-trip times between hosts.

Decipher encrypted traffic

Measure throughput between hosts

Do port scans over a range of ports at a target host.

With SYN ******s, when a server receives a SYN segment, it returns a SYNACK with:

with an initial sequence number that is a hash of the IP addresses and port numbers in the SYN segment (as well as of other things).

with a randomly chosen initial sequence number;

initial sequence number 1;

none of the above.

10.

Over a TCP connection, suppose host A sends two segments to host B, host B sends an acknowledgement for each segment, the first acknowledgement is lost, but the second acknowledgement arrives before the timer for the first segment expires.

Host A will retransmit the second segment

Host A will retransmit the first segment

Host A will retransmit both segments

Host A will retransmit neither segments

11.

Consider an HTTP Web server using persistent connections. Suppose the server spawns a separate process for each client that connects to the server. Then each of these spawned processes will have different server port numbers.

True

False

12.

Host A is sending host B a large file over a TCP connection. Assume host B has no data to send A. Host B will not send acknowledgements to host A because host B cannot piggyback the acknowledgements on data.

True

False

13.

The size of the TCP RcvWindow never changes throughout the duration of the connection.

True

False

14.

Suppose host A is sending a large file to host B over a TCP connection. If the sequence number for a segment of this connection is m, then the sequence number for the subsequent segment will necessarily be m+1.

True

False

15.

The TCP segment has a field in its header for RcvWindow.

True

False

16.

Suppose that the last SampleRTT in a TCP connection is equal to 1 sec. Then Timeout for the connection will necessarily be set to a value >= 1 sec.

True

False

17.

Suppose host A sends host B one segment with sequence number 38 and 4 bytes of data. Then in this same segment the acknowledgement number is necessarily 42.

True

False

18.

Suppose that host A wants to send data over TCP to host B, and host B wants to send data to host A over TCP. Two separate TCP connections - one for each direction - are needed.

True

False

19.

The MSS is the maximum size of a TCP segment including headers.

True

False

20.

In TCP, the acknowledgement number that a host puts in a segment is the sequence number of the next byte the host is expecting from the sender.

True

False