III. Computation: C1-5. （55 points in total ). Th...

III. Computation: C1-5. (55 points in total ). The process/procedure or explanation of computation and the correct results are all wanted. C1. (10 points) Consider building a CSMA/CD network running at 100Mbps over a 2-km cable with no repeaters. The signal speed in the cable is 20,000 km/sec. What is the minimum frame size？ C2. (13 points) A bit stream 0110110 is transmitted using CRC method. The generator polynomial is x3+ x2+1. a) How many check bits should be added？ b) Show the actual bit string transmitted by the sender end. c) Suppose that the second bit from the left is inverted during transmission. Show that this error will be detected by the receiver. C3. (10 points) A channel has a bit rate of 64 kbps and a propagation delay of 2 msec. For what range of frame sizes does stop-and-wait give an efficiency of at least 80 percent？ C4. (12 points) A router has the following entries in its routing table: Address/Mask Next hop 130.96.39.0/24 Interface 1 130.96.39.128/25 Interface 0 130.96.40.0/25 Router 1 192.4.10.0/23 Router 2 Default Router 3 For each of the following IP addresses, what does the router do if a packet with that address arrives？ Please state why you choose it. 1) 192.4.11.172 2) 130.96.39.135 3) 130.96.39.96 4) 130.96.40.168 5) 130.96.40.64 C5. (10 points) In a subnet, distance vector routing is used, and the following vectors have just come in to router D: from B: (5, 0, 8, 12, 6, 2); from C: (16, 12, 0, 6, 9, 10); and from E: (7, 6, 3, 9, 0, 4). The measured delays to B, C, and E, are 6, 8, and 5, respectively. What is D's new routing table？ Give both the outgoing line to use and the expected delay.