GO test series

Question

What are the possible options for X?

Comments

X = 4001
Y = 9501

Answer 1

Answer will be 4001

In C part, Receiver has sent ack 4001. It means receiver is expecting segment with sequence number 4001.
so only possible value of X is 4001.

for Y, if we assume that in C part, no data is sent by receiver then value of Y will be 9501. as FIN segment consumes 1 sequence number

Comments

But after phase C, client cannot send data so how does it make sense by using X = 4001 pure ACK segment? that's the doubt

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After receiving C segment, that is FIN, client has to send Ack of that (last ack). And all segments, including pure ack, must have a sequence number. Though in case of pure ack, sequence number will not be considered, and will be used again.