Question

true or false for (number 1)

1.Selective repeat protocols only retransmits packets that were lost or corrupted at the receiver.

2.Consider the acknowledgment for a packet with sequence number n. A __________ acknowledgment indicates that all packets up to and including n have been correctly received.

complete

comprehensive

consistent

cumulative

3.The maximum amount of data that can be placed in a segment is limited by the

congestion window.

maximum segment size.

maximum transmission unit.

send buffer.

4.Which of the following protocols will NOT buffer out of order packets?

GBN

SR

TCP

All of the above buffer out of order packets.

5.The acknowledgment number in a TCP segment is the sequence number of

the most recently received in-order packet.

an individual correctly received packet.

the next byte that is expected.

All of the above are correct.

6.Which of the following is considered a TCP loss event?

The occurrence of a timeout.

Receipt of three duplicate ACKs.

Both of the above.

None of the above.

7.TCP Tahoe cuts its congestion window to 1 MSS after

a timeout event.

a triple duplicate ACK.

Both of the above.

None of the above.

Answer 1

1.Selective repeat protocols only retransmits packets that were lost or corrupted at the receiver.

Answer: TRUE

Selective repeat protocols is mostly identical to GBN protocol, except that buffers are used at both the receiver, and the sender. Both receiver and sender each maintain a window of size.

Sender’s Windows ( Ws) = Receiver’s Windows ( Wr).

2.Consider the acknowledgment for a packet with sequence number n. A __________ acknowledgment indicates that all packets up to and including n have been correctly received.

complete

comprehensive

consistent

cumulative

Answer: cumulative

Cumulative Acknowledgment acknowledges that receiver has correctly received a packets which implicitly informs the sender that the previous packets were already received correctly.

3.The maximum amount of data that can be placed in a segment is limited by the

congestion window.

maximum segment size.

maximum transmission unit.

send buffer.

Answer: maximum transmission unit.

MTU determines the maximum size of each packet in any transmission.

4.Which of the following protocols will NOT buffer out of order packets?

GBN

SR

TCP

All of the above buffer out of order packets.

Answer: GBN

In GBN receiver only have 1 slot in window size which only use to accomodate ordered packets. if any unordered packet reciver receiver discard the packets and retransmits all the frames that sent after the frame which suspects to be damaged or lost.

5.The acknowledgment number in a TCP segment is the sequence number of

the most recently received in-order packet.

an individual correctly received packet.

the next byte that is expected.

All of the above are correct.

Answer: the next byte that is expected.

6.Which of the following is considered a TCP loss event?

The occurrence of a timeout.

Receipt of three duplicate ACKs.

Both of the above.

None of the above.

Answer: Both of the above.