(a) Assume a Sliding Window with Go-Back N ARQ is being used on a transmission l

Question

(a) Assume a Sliding Window with Go-Back N ARQ is being used on a transmission link with a 3-bit sequence number. The transmitter has previously sent frames with sequence numbers 0, 1 and 2. Is the transmitter allowed to send a frame with sequence number 3 if the frame with sequence number 2 has not been acknowledged? Explain your answer.

(b) Assume a Sliding Window with Go-Back N ARQ is being used on a transmission link with a 3-bit sequence number. 1. If the transmitter sends frames 0, 1, 2, and 3, how many more frames can be sent without an acknowledgment returned by the receiver? 2. If the receiver sends back ACK 2, how many more frames can be sent? What are their frame numbers?

(c) Assume a Sliding Window with Selective-Reject ARQ is being used on a transmission link with a 3-bit sequence number. Host A sends frames 0, 1, and 2 to Host B and frame 0 is lost. 1. How many more frames can be received by Host B? 2. What would be the frame number in the Select Rej frame sent back by Host B?

Explanation / Answer

(a) Assume a Sliding Window with Go-Back N ARQ is being used on a transmission link with a 3-bit sequence number. The transmitter has previously sent
frames with sequence numbers 0, 1 and 2. Is the transmitter allowed to send a frame with sequence number 3 if the frame with sequence number 2 has not been
acknowledged? Explain your answer.

Answer :: Yes it will allow to send frame 3 as frame size is of 3 and frame 0 and 1's acknoledge has been received so frame 2 will be retransmitted if its not get the
acknoledgement later on.

(b) Assume a Sliding Window with Go-Back N ARQ is being used on a transmission link with a 3-bit sequence number.
1. If the transmitter sends frames 0, 1, 2, and 3, how many more frames can be sent without an acknowledgment returned by the receiver?

Answer ::    only 3 frames can be sent as frame size if 3 so 0 1 2 will send and frame 3 will be sent after acknowledgment received of frame 0

2. If the receiver sends back ACK 2, how many more frames can be sent? What are their frame numbers?

Answer ::    if ack of frame 2 is received then 3 more frames can be sent so frame number 3 4 & 5 can be able to sent.

(c) Assume a Sliding Window with Selective-Reject ARQ is being used on a transmission link with a 3-bit sequence number. Host A sends frames 0, 1, and 2
to Host B and frame 0 is lost.
1. How many more frames can be received by Host B?

Answer ::    no more frames can be sent until frame 0 is not getting retrasmitted. as window size will be locked until frame 0 is not acknowledged.
  
2. What would be the frame number in the Select Rej frame sent back by Host B?

Answer ::    frame number 1 and 2 will be rejected as its already acknowledged to host A

Thanks

Related Questions

Navigate

• Browse (All)
• Browse #
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.