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Mohamed G. Gouda						Midterm 1
CS 356: Computer Networks					Spring 2008
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Open Book							75 Minutes
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1. (10 points)

Assume that the Resource/Allocation Protocol in Section 4.5 is to be
simplified as follows: the s resources in the protocol are all of the
same kind. Thus, the exchanged messages between a user u[i] and
controller c in the simplified protocol are rqst, grant, and rls
(instead of rqst(r), grant(r), and rls(r), respectively). Use the AP
notation to specify the controller c in the simplified protocol.

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2. (10 points)

Consider a protocol that consists of two processes p and q. Process p
sends rqst(i) messages to process q and q replies by sending back a
rply(i) message for each rqst(i) message that it receives from p, where i is
in the range 0..n-1 and n is a declared constant in p and q. Process p
can send a rqst(i) message only after it has sent a rqst(i-1 mod n) message
and only after it has received a rply(i) message for the last rqst(i) message
that p has sent earlier to q. Assuming that the exchanged messages between
p and q can be reordered but neither lost nor corrupted, specify
processes p and q. 

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