Here A,B,C are 3 networks and a packet sends from A to C . When packet 180 B sends from A to B it is connected with 20B IP header as well as 20 B TCP header. In network B we are segmenting data packet as 100 B and we are removing IP header of A and it never comes back again for calculation. right?
But then we can see TCP header is never removed and it is calculated as part of header send to destination C.
My question is if IP header are different for network A, B,C then how TCP header will be same for network A,B,C?