s9 - CMPEN/EE 362 Asst. 9 Solution Spring 2009 Problem 1....

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CMPEN/EE 362 Asst. 9 Solution Spring 2009 Problem 1. Text Problem 5.8. Give two answers. In one, the answer if one of the alternatives is the least cost path and the other is as good as possible. In the other answer, don’t worry about how good the two paths are. Solution. First case: Pick the least cost route and remove all lines used for the route. Then run the shortest path algorithm to find the shortest path for this reduced network, if there is such a path. The two paths have no two lines in common (it is OK if they have a router in common), so a failure in any line of one path will not affect the other. Second case. If there is no second path after the least cost is removed, there still may be two routes, but neither is least cost. Example: Removing the least cost route (cost 4) lines from A to B disconnects A and B. But there are two paths with no common lines, with path costs 9 each. As long as there is no cut between A and B which divides the network in two parts with only one connecting link, the problem is solvable for the second case.
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This note was uploaded on 09/23/2009 for the course CMPEN 362 taught by Professor Johnmetzner during the Spring '09 term at Pennsylvania State University, University Park.

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s9 - CMPEN/EE 362 Asst. 9 Solution Spring 2009 Problem 1....

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