isro 2015 set c

Question

Q   An ACK  number of 1000 in TCP always means that

option 

a) 999 bytes have been successfully received.

b) 1000 bytes have been successfully received.

c) 1001 bytes have been successfully received.

d) none of the above

Answer 1

d) none of the above

as ack no tell the next expected byte to be received..

Comments

but it also confirm that previous segment is received...likewise 999 received

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oh ya..actually it depends on sequence number. if sequence no. will start from 900 then Ack of 1000 will tell only 100 bytes received. so it should be (D)

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kk but in this where are u given that start from 900 or it will send 100 bytes of a data at a time