$($a$)$ A web browser establishes a HTTP session with a web server over a TCP connection. The browser and server are each hosted on Ethernet LAN, which connects to the Internet. In respond to a HTTP request, the server sends a file of $2000$ bytes to the browser. $($i$)$ Examine the session$-$layer function of the TCP$/$IP architecture model and illustrate how the HTTP session is identified at the web server. $(5$ marks$)($ii$)$ Examine the IP$-$layer function of the TCP$/$IP architecture model and illustrate how the HTTP connection between the end$-$hosts are identified. $(5$ marks$)($iii$)$ Examine the network$-$layer function of the TCP$/$IP architecture model and estimate the size of the final IP packet $($including its header$)$ transmitted to the web browser. Hint: MTU for Ethernet LAN is $1500$ bytes.