Question

Problem (1) A LAN is setup where two computers (A and B) are connected in a star topology to a hub (H1) at distances of 1Om and 20m and with BERs of 5E-6 and 1E-5 respectively. Hub H1 is connected directly to another hub (H2) at a distance of 50km and with a BER of 1E-6. Two computers (C and D) are connected to hub H2 at distances 50m and 20m respectively with BERs of 1E- 3 each. The data rate of each computer to its hub is 10 Mbps. Link Hl<->H2 has a data rate of 100 Mbps. Assuming data can travel at 2.8 10 8 m/sec for all links, answer the following questions. (a) Diagram this network. (5 points) (b) What is the propagation delay between computers A and C? (2 points) (c) What is the propagation delay between computers B and D? (2 points) (d) If A serves frames of data that consist of 2000 characters (8-bit per character), what is the transmission delay for a block from computer A to computer D? (4 points) (e) What is the line utilization of link H1H2 (based on employing an IdleRQ scheme where the processing times of the Information and ACK/NAK frames and the transmission time of the ACK/NAK frames are negligible) for the blocks described in (d)? (4 points) (f) What is the probability that a block will be in error going from computer A to D? Use the block size provided in (d). (3 points)