SIT202 Computer Networks

1. Consider a scenario where a web portal uses cookies to track the users and provides a customized view to the individual user based on the previously visited sites. The web portal sends a cookie to the browser which is stored in the browser at the client’s side along with the visited sites. This helps to keep track the previously visited pages of a client from different sites. Prepare a diagram illustrating how the cookie is used between a browser and the web portal when a user revisits the web portal and how the pages are retrieved from different webservers to provide a customized view to the user. Consider two different webservers for two visited sites, a web portal and a client in your diagram. Explain the steps of your diagram.

Marking guideline:

Prepared diagram and explained well with all servers and client as mentioned, with request, response and cookies, retrieved pages from servers.

Answer has missing components or errors from any two of the following components (servers, client, portals, request, response, cookie, retrieved pages from servers) and corresponding error in the explanation.

Answer has missing components or errors from any four of the following components (servers, client, portals, request, response, cookie, retrieved pages from servers) and corresponding error in the explanation.

Answer has missing components or errors from any 6 of the following components (servers, client, portals, request, response, cookie, retrieved pages from servers) and corresponding error in the explanation.

2. In the following diagram, a web client is communicating with a web server which opens a TCP connection at client’s end. The client is using an initial sequence number (ISN) 2048 with a port of 51000 and receiving window size of 2000. In response, server also opens a TCP connection with ISN 21732 and receiving window size of 4000, port 80. After connection establishment, client sends two data segments each of size 500 bytes. Then server responds in a single segment with 1000 bytes. Then client closes the connection, in response server also closes the connection.