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2. Network design is often partitioned into a multi-layer hierarchy with each layer data link layer
3. How many cables does a wired telephone network consisting of 100 users need if it 100*99/2 = 4950
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EECS 3213!
Assignment 1 Solutions!
Fall 2014
4. You need to operate at error-free rates of 24-kbps through a channel with a 1.6 I)
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5. What kind of switching do wire-line telephone and telegraph provide? !
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telegraph: message switching, connectionless!
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8. Name two types of round robin networks.
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EECS 3213!
Assignment 1 Solutions!
Fall 2014
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10. You are using a R = 2.3-Mbps link and notice a 15-MB file downloaded in 1.3
seconds Throughput = 15*8*1e6/1.3 = 92.3 Mbps
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EECS 3213!
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Fall 2014
12. For a link with a data rate of 10 Gbps communicating over a distance of 5000km (Problem 1.15 from the textbook)!
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EECS 3213!
13. Assignment 1 Solutions!
Fall 2014
If switching time is 10 μs (microseconds) in a store-and-forward packet-switching If v = 2e5 km/s or 200 m/us (us is “microsecond”) in 10 us the signal travels 2 km.
Therefore each switch adds the equivalent of 2 km of extra cable. Even going
through 10 routers we only add the equivalent of 20 km to what is otherwise a
4,500 km distance. Thus, the router addition is not likely to have a big impact.
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