1. Probabilistic Verification
of Go-Back-N
Tong Wang tw2436
Yihan Zou yz2575
Hang Yin hy2368
Miaoqiong Wang mw2908

2. Assumptions RTT >> Tx: multiple messages on channel
FC and BC are FIFO queues: packets arrive in order
Sender/ Receiver can only process one packet at a time
Sender always has packet to send
Timeout occure
Stopping conditions
Initial state: ( 0 0 (0,1,2,3) ( ) )

3. Timeout Backward channel is empty
Both forward and backward channel is empty

4. Stopping points 3 lost packages on the channel
ACK0 is successfully received

5. Global state (Tx, Rx, FC, BC)
Four stacks: stack(i) contains states going through i low probability transitions

7. Initial
(0 0 (0,1,2,3) ()) Get M0, Get M1, Get M2, Get M
step 1 Pop (0 0 (0,1,2,3) ())
(0 1 (1,2,3) (0)) Get M0, Get M1, Get M2, Get M3, Acpt M
(0 0 (1,2,3) ()) Get M0, Get M1, Get M2, Get M
step 2 Pop (0 1 (1,2,3) (0)) ,(1 1 (1,2,3,4) ()) is accepted
(0 2 (2,3) (0,1)) Get M0, Get M1, Get M2, Get M3, Acpt M0, Acpt M1 0
(0 1 (1,2,3) ()) Get M0, Get M1, Get M2, Get M3, Acpt M
(0 1 (2,3) (0)) Get M0, Get M1, Get M2, Get M3, Acpt M
(0 0 (1,2,3) ()) Get M0, Get M1, Get M2, Get M
step 3 Pop (0 2 (2,3) (0,1)) ,(1 2 (2,3,4) (1)) is accepted
(0 3 (3)(0,1,2)) Get M0, Get M1, Get M2, Get M3, Acpt M0, AcptM1, AcptM2 0
(0 2 (2,3) (1)) Get M0, Get M1, Get M2, Get M3, Acpt M0, Acpt M1 1
(0 2 (3) (0,1)) Get M0, Get M1, Get M2, Get M3, Acpt M0, Acpt M1 1

8. Thank you!