How can the pseudoheader in TCP contain IP address while it works at the transport layer level?Also the pseudoheader will be included in the TCP checksum calculation.Is that because of the interface between the networklayer and transportlayer?Or because of the socket address that works at layer4?
Actually what I mean is-
Pseudo header that is appended to the tcp/udp header contains the IP addresses of source and the destination.Consider at the sender's side .How does the sender know the destinationIP address at layer4?It's only when the packet arrives at the layer3 the sender can know the destination IP .Then how the checksum at layer 4 is caculated with the src IP ,dest IP fields filled?
PLZ reply.
