1. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol1 UC Berkeley WOW Wireless Token Ring Protocol (WTRP) A Medium Access Control Protocol for QoS Aware Wireless Networks Mustafa Ergen, Duke Lee, Ruchira Datta, Jeff Ko, Roberto Attias, Anuj Puri, Raja Sengupta, Starvros Tripakis, and Pravin Variaya

2. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol2 UC Berkeley WOW Automated Vehicle Platoon Real-time safety critical control over ad-hoc network Vehicles transmit control data in round robin every 20 ms Wireless Quality of Service

3. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol3 UC Berkeley WOW Merge Lane Distributed solution Need wireless QOS Admission control

4. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol4 UC Berkeley WOW Motivations for WTRP Quality of service (real time applications) Distributed solution (robust against a single node failure) Flexible topology (token ring can be created with Pico cells) Safety critical applications (need fast recovery from failure) No need for clock synchronization (compared to TDMA) Partial connectivity (hidden terminal problem)

5. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol5 UC Berkeley WOW Motivations for WTRP Quality of service (real time applications) Distributed solution (robust against a single node failure) Flexible topology (token ring can be created with Pico cells) Safety critical applications (need fast recovery from failure) No need for clock synchronization (compared to TDMA) Works on partial connectivity (no hidden terminal problem)

6. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol6 UC Berkeley WOW Motivations for WTRP Quality of service (real time applications) Distributed solution (robust against a single node failure) Flexible topology (token ring can be created with Pico cells) Safety critical applications (need fast recovery from failure) No need for clock synchronization (compared to TDMA) Works on partial connectivity (no hidden terminal problem) centralized (802.11 PCF, Bluetooth)distributed (token ring)

7. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol7 UC Berkeley WOW Motivations for WTRP Quality of service (real time applications) Distributed solution (robust against a single node failure) Flexible topology (token ring can be created with Pico cells) Safety critical applications (need fast recovery from failure) No need for clock synchronization (compared to TDMA) Works on partial connectivity (no hidden terminal problem) 14312 TDMA

8. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol8 UC Berkeley WOW Motivations for WTRP Quality of service (real time applications) Distributed solution (robust against a single node failure) Flexible topology (token ring can be created with Pico cells) Safety critical applications (need fast recovery from failure) No need for clock synchronization (compared to TDMA) Works on partial connectivity (no hidden terminal problem)

9. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol9 UC Berkeley WOW Additional Challenges From Wireless Medium Partial connectivity (unable to hear all nodes in a ring) Support for multiple rings Self-managed admission control Frequent packet loss, corruption

10. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol10 UC Berkeley WOW Solutions: Connectivity Table Each node builds and updates connectivity table that contains information of all stations in its reception range, and transmission order of the nodes in its ring

11. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol11 UC Berkeley WOW Solutions: Connectivity Table Each node builds and updates connectivity table that contains information of all stations in its reception range, and transmission order of the nodes in its ring

12. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol12 UC Berkeley WOW Ring Recovery B fails or moves out of range. A tries to transmit to its successor (B) a specified number of tries and determine that communication link to B is bad. AB C D E F 2. SET_PRED A 1. Retransmit TOKEN 0. Transmit TOKEN

13. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol13 UC Berkeley WOW Solutions: Unique Ring Address Each ring has unique ring id based on unique MAC address of one of the stations of the ring.

14. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol14 UC Berkeley WOW Solutions: Unique Priority of Token Based on ring address and generation sequence number pair. Station only accept token that has higher priority than the last token that the station has accepted. ring addressgeneration sequence …

15. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol15 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 1 1 1 6 1 2 2 6

16. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol16 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 2 1 1 6 6 2 2 6

17. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol17 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 2 2 1 6 6 6 2 6

18. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol18 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 6 2 2 6 6 6 2 6 At next step Delete token with generation sequence number 2 since the next node has seen token with generation sequence number 6

19. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol19 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 6 6 2 6 6 6 6

20. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol20 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 6 6 6 6 6 6 6

21. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol21 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 6 6 6 7 6 6 7 Token refreshed by owner

22. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol22 UC Berkeley WOW Token Recovery (Multiple Tokens Resolution) 6 6 6 7 7 6 7

23. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol23 UC Berkeley WOW Token Recovery (Ring Address Resolution) 6 6 6 7 6 6 6 Suppose that the owner of the token has failed

24. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol24 UC Berkeley WOW Token Recovery (Ring Address Resolution) 6 6 6 7 8 6 This node detects that the owner is down and claims the token 8

25. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol25 UC Berkeley WOW Token Recovery (Ring Address Resolution) 6 6 6 7 8 8 8

26. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol26 UC Berkeley WOW Token Recovery (Ring Address Resolution) 8 6 6 7 8 8 8

27. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol27 UC Berkeley WOW QOS Interface High Priority Applications (6)Low Priority Applications (6,3) Wireless Token Ring Protocol (10) Register 6

28. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol28 UC Berkeley WOW QOS Interface High Priority Applications (6)Low Priority Applications (6,3) Wireless Token Ring Protocol (4) Granted Register 6

29. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol29 UC Berkeley WOW QOS Interface High Priority Applications (6)Low Priority Applications (6,3) Wireless Token Ring Protocol (4) GrantedHandler Register 3

30. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol30 UC Berkeley WOW QOS Interface High Priority Applications (6)Low Priority Applications (6,3) Wireless Token Ring Protocol (1) Granted

31. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol31 UC Berkeley WOW WTRP Deliverables (2001) WTRP Software Core UDP CORE UDP Implementation IP API WTRP Software Core KERNEL CORE LINUX KERNEL Implementation IP Driver WTRP Software Core SIMULATOR CORE SIMULATOR Implementation Channel Model Front End http://wow.eecs.berkeley.edu

32. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol32 UC Berkeley WOW UDP: Video Streaming

33. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol33 UC Berkeley WOW Simulation Front End

34. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol34 UC Berkeley WOW A B A B A B 1 3 2 Token Rotation Time Vs. Rotation C C C

35. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol35 UC Berkeley WOW Fairness

36. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol36 UC Berkeley WOW Throughput Comparison With 802.11 DCF

37. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol37 UC Berkeley WOW Conclusions The wireless token ring protocol (WTRP) is a medium access control protocol for wireless networks in mission critical systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults.

38. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol38 UC Berkeley WOW Conclusions The wireless token ring protocol (WTRP) is a medium access control protocol for wireless networks in mission critical systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults.

39. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol39 UC Berkeley WOW Conclusions The wireless token ring protocol (WTRP) is a medium access control protocol for wireless networks in mission critical systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults.

40. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol40 UC Berkeley WOW Conclusions The wireless token ring protocol (WTRP) is a medium access control protocol for wireless networks in mission critical systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults.

41. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol41 UC Berkeley WOW Conclusions The wireless token ring protocol (WTRP) is a medium access control protocol for wireless networks in mission critical systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults.

42. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol42 UC Berkeley WOW Conclusions The wireless token ring protocol (WTRP) is a medium access control protocol for wireless networks in mission critical systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults.

43. July 15, 2002 SCI02 ORLANDO Wireless Token Ring Protocol43 UC Berkeley WOW Conclusions The wireless token ring protocol (WTRP) is a medium access control protocol for wireless networks in mission critical systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults.