Consider the latency model for dynamic congestion windows. Which of the following
components contribute to latency
Your Answer: round trip time, RTT
Correct Answer: all of the above
2.
When a TCP segment arrives to a host, the socket to which the segment is
directed depends on
Your Answer: all of the above
3.
UDP has which of the following characteristics:
Your Answer: none of the above
4.
When a UDP segment arrives to a host, in order to direct the segment to the
appropriate socket, the OS uses
Your Answer: the destination port number
5.
The stop-and-wait protocol is highly inefficient when
Your Answer: when there is a large distance between source and destination and the
transmission rate is low
Correct Answer: when there is a large distance between source and destination and the
transmission rate is high
6.
Pipelining requires which of the following
Your Answer: all of the above
7.
TCP applies fast retransmit to a segment when
Your Answer: when it receives three ACKs for an earlier segment
8.
Nmap is often used to:
Your Answer: Do port scans over a range of ports at a target host.
9.
With SYN cookies, when a server receives a SYN segment, it returns a
SYNACK with:
Your Answer: with a randomly chosen initial sequence number;
Correct Answer: 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).
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.
Your Answer: Host A will retransmit neither segments
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.
Your Answer: False
2.
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.
Your Answer: False
3.
The size of the TCP RcvWindow never changes throughout the duration of the
connection.
Your Answer: True
Correct Answer: False
4.
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.
Your Answer: False
5.
The TCP segment has a field in its header for RcvWindow.
Your Answer: True
6.
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.
Your Answer: True
Correct Answer: False
7.
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.
Your Answer: False
8.
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.
Your Answer: False
9.
The MSS is the maximum size of a TCP segment including headers.
Your Answer: False
10.
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.
Your Answer: True