20190309sol

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1 - Exercise (6 points) Consider the network below, where links are twisted-pair cables. At time t=0, hosts A and B start sending the following sequences of packets (one immediately after the other): From A, 3 packets with destinations: C, D, C- From B, 2 packets with destinations: C, D- The first packet from B crosses the routers R3-R1-R2, while the second packet from B crosses the routers R3-R2. All the packets from A follow the same route through R1-R2 - All the packets have equal length, and each comprises a header of h=4 byte and a payload of p=26 byte. All the nodes operate in the store-and-forward mode. Using a time diagrams, compute the arrival time of each packet to destination. 03/09/2019 domenica 15 settembre 2019 18:55 FCN 2018-19 Pagina 1 FCN 2018-19 Pagina 2 2 - Exercise (6 points) Consider the network below, in which the cost of each link is reported near the link. Assume that the dashed link BL is planned but still not in operation. Apply the Dijkstra algorithm to compute the shortest-path tree form node M to all the other nodes. Draw the tree on the right of the table and fill-in the top routing table of M node. 1- Compute the maximum value of X that allows an affective reduction of the distances between M and the other nodes (when possible). Repeat point 1 and fill in the bottom table 2- FCN 2018-19 Pagina 3 3 - Exercise (6 points) A private company owns the following IP addressing space: 139.27.80.0/22. The network is shown in the picture below. The company has five departments with the following requirements in terms of connected hosts: Dept. A: 20 hosts Dept. B: 260 hosts Dept. C : 100 hosts Dept. D: 250 hosts Dept. E: 13 hosts Finally, pp1 to pp3 are point-to-point links to connect the routers. Define a subnetting plan for the company overall…