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Pagina 1 di 9 Fundamentals of Communication Networks Prof. G. Maier Exam – 22 January 2018 Surname Name Student ID Total time 2:00 Ex1 (7pt) Ex2 (6pt) Ex3 (6pt) Ex4 (5 pt) Ques (8 pt) 1 - Exercise (7 points) Consider the network below. At time t=0 the client (web browser) C starts an HTTP session to get from a server S a web page composed by an HTML document of length LHTML = 1 kbyte and one linked object of size LOBJ = 20 kbyte. C is connected to an HTTP proxy P that has the linked object stored in the cache, but not the HTML document. Assume that all the connections are persistent (HTTP v1.1) and all headers and control messages are of negligible length. Compute the time t=T at which the web browser has fully downloaded the web page. Apply the fair-sharing model to compute the average rates for each connection, assuming that there is a TCP connection always active for the whole duration of the download from client X to server S (suggestion: note that the connections C-P and P-S transfers data in different time intervals). Make use of the time diagrams to visualize the web-page acquisition. Pagina 2 di 9 Pagina 3 di 9 2 - Exercise (6 points) An ISP owns the following IP addressing space : 15.36.182.0 netmask 255.255.254.0. The ISP network is shown in the picture below. The number of hosts requested is reported inside each network . Assume each switch connected to hosts has 26 ports , fully occupied. Define an addressing plan for the network able to support all necessary addresses for each subnet. Indicate graphically on the figure the IP subnets (identify boundaries) and assign a letter to each subnet in increasing alphabetical order according to the number of hosts (A  largest network, etc.). For each subnet define address, netmask, direct broadcast address. Display…