educative.io

Why is the ack number 2553

Courses
,
#1

A TCP segment is sent with the value 2503 in the sequence number field and a payload of 50 bytes. The receiver sends back a segment containing the value ______ in the acknowledge field.

couldn’t understand clearly here.is it the ack the reciever sending back?
and how would the reponse of ack would be?

Type your question above this line.

Course: https://www.educative.io/collection/10370001/6105520698032128
Lesson: https://www.educative.io/collection/page/10370001/6105520698032128/5652844986236928

#2

Hi @GreedyCat

The acknowledgment number is basically like an acknowledgment sent back to the sender by the receiver. This tells the sender that the receiver has received the data.

So in this question, the segment number was “2503” and the sender is sending data that is of “50 bytes”.

So the receiver will add the data number of bytes received into the segment number.
2503 + 50 = 2553

This helps TCP to identify if a segment was missing if the acknowledgment number doesn’t match the (segment + data bytes) sent at sender’s end.

Thanks,

1 Like
#3

So if the segment sent back has an acknowledgment number of 2553, does this mean the next segment will have a sequence number starting at 2554? Or 2553?