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

2. Agenda
Assumptions
Stopping Procedure
Table

3. Assumptions Tuple observed includes: Sender state Receiver 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