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Selective-Reject ARQ Systems

Consider a selective-reject ARQ system with a window size of 3.

a) Circle (or shade or bold) the sender window after frames 0 through 3 have been sent and ACK 2 has been received

0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0

b) Circle (or shade or bold) the sender windows after frames 4 through 6 have been transmitted, ACK 5 and NAK 5 are received.

0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0

c) After a) and b) have occurred, which frames need to be resent?

d) After a) and b) have occurred, which frames have been acknowledged?

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[2] Consider a selective- reject ARQ
Posting

Consider a selective-reject ARQ system with a window size of 3.
=============================================
a) Circle (or shade or bold) the sender window after frames 0 through 3 have been sent and ACK 2 has been received

0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0

=================================================
Window [0,2] [3-5]
SN
Node A

Node B
RN

Packets
Delivered 0 1 2

b) Circle (or shade or bold) the sender windows after frames 4 through 6 have been transmitted, ACK 5 and NAK 5 are received.

0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0

Window [4,6] [5,7]
SN
Node A

Node B
RN

Packets
Delivered 4

c) After a) and b) have occurred, which frames need to be resent?
5,6,7

d) After a) and b) ...

Solution Summary

This job emphasizes a selective-reject ARQ system with a window size of 3.

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