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4.2 a. Suppose that the current replay window spans from 120 to 530. If the next incoming authenticated packet has sequence number 340, what will the receiver do with the packet, and what will be the parameters of the window after that? (3 Marks)
b. If instead the next incoming authenticated packet has sequence number 598, what will the receiver do with the packet, and what will be the parameters of the window after that? (3 Marks)
c. If instead the next incoming authenticated packet has sequence number 110, what will the receiver do with the packet, and what will be the parameters of the window after that? (3 Marks)
d. The IPsec architecture document states that when two transport mode SAs are bundled to allow both AH and ESP protocols on the same end-to-end flow, only one ordering of security protocols seems appropriate: performing the ESP protocol before performing the AH protocol. Why is this approach recommended rather than authentication before encryption? (3 Marks)
e. Where does IPsec reside in a protocol stack? (3 Marks)