hw1_fall10 - CS 421 HW#1, due Nov. 8, 2010 1) Given the...

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CS 421 HW#1, due Nov. 8, 2010 1) Given the following parameters for a datagram packet switching network: N: number of hops between two given stations; L: total number of bits to be Xmitted; B: common data rate, in bits/second, on all links; H: number of overhead bits per packet; P: packet size, in bits (excluding overhead bits); D: propagation delay per hop, in seconds. Derive a general expression for end-to-end delay between the two stations. Assume L is a multiple of P, and that the processing and queueing delays in each node are negligible. 2) Suppose that you are required to use the Stop-and-Wait protocol for reliable communication over a 100 Mbps (100 x 10 6 bps) channel with an end-to-end distance of 6000 km. Each packet sent by the sender is 1000 bytes long. Assume that the speed of propagation is 3 x 10 5 km/s and ignore all other sources of delay other than the propagation delay. ACK packets have negligible transmission times. What is the utilization of the channel, U, which is defined as the fraction of time the sender is busy sending bits into the channel? 3) Consider a 1 Mbps channel with a 20 msec one-way propagation delay, i.e., 40 msec roundtrip propagation delay. We want to transfer a file of size 13500 Bytes. Each packet has a total size of 1625 Bytes including the 125 Bytes header, i.e., each packet contains 1500 Bytes of data. When
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hw1_fall10 - CS 421 HW#1, due Nov. 8, 2010 1) Given the...

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