Probabilistic Search Verification of the Go-Back-N Protocol

1. Adeyemi Aladesawe Annjana Ramesh Lingxue Li Nanjun Lu Probabilistic Search Verification of the Go-Back-N Protocol

2. Agenda • Assumptions • Stopping Procedure • Table

3. Assumptions • Tuple observed includes: • Sender state • The oldest message yet to be acknowledged • Receiver state • The expected message number • Message no. on forward channel • Acknowledgment no. on reverse channel • The no. of message expected by the receiver • Window size • Probability level • Service Sequence

4. Assumptions • Message/Acknowledgement placed on the channel is received or lost by the receiver/sender in one state transition • There are two conditions on the duplex channel • Only a message on the forward channel • Message on the forward, Ack on the reverse • If message only, it can either be received or lost • If both message and ack, then: • Message and ack can be lost • Message can be lost, ack can be received • Message can be received, ack can be lost • Message and ack can be received

5. Assumption • If only one loss condition (message or ack), we drop down one probability level • If both message and ack lost, we drop down two probability level • The message processing time at the receiver is negligible • Cumulative acknowledgement is used

6. Stopping Procedure • On each probability level, we stop when we successfully send 1 message after 3 message losses (based on the problem statement of considering up to 3 message loss) • This is because the sequence will successfully repeat henceforth

7. Project split up Member - Assignment • Lingxue – State transition diagram • Adeyemi – Pseudo code/algorithm for the program • Annjana – Program • Nanjun - Table