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Unformatted text preview: that at time t , the next in-order packet that the receiver is expecting has a sequence number of k . Assume that the medium does not reorder messages. a What are the possible sets of sequence numbers inside the sender’s window at time t ? Justify your answer. b What are all possible values of the ACK ﬁeld in all possible messages currently propagating back to the sender at time t ? Justify your answer. Problem 4 Consider a reliable data transfer protocol that uses only negative acknowledgments. Suppose the sender sends data only infrequently. Would a NAK-only protocol be preferable to a protocol that uses ACKs? Why? Now suppose the sender has a lot of data to send and the end-to-end connection experiences few losses. In this second case, would a NAK-only protocol be preferable to a protocol that uses ACKs? Why? Page 1 of 1...
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This note was uploaded on 04/28/2010 for the course CS 118 taught by Professor Chu during the Spring '08 term at UCLA.
- Spring '08