 | 1 | initial version |
Window size will be announced in each package. When a packet is received, the packet is stored in the receive buffer. And when the receiver then sends a packet to the sender, for example an ACK, this ACK contains the current size of the buffer. It depends on the situation, but usually you can see that the buffer has shrunk by the size of the received segment. The first packets where the Window Sizes are advertised are the SYN packets.
But maybe you mean the Window Scaling Factor. This value is only advertised in the SYN packets.
