July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 1

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

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 2

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

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 3

UC Berkeley WOW

Merge Lane

Distributed solutionNeed wireless QOSAdmission control

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 4

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)

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 5

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)

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 6

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)

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 7

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)

1 43 12

TDMA

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 8

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)

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 9

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

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 10

UC Berkeley WOW

Solutions: Connectivity TableEach 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

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 11

UC Berkeley WOW

Solutions: Connectivity TableEach 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

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 12

UC Berkeley WOW

Ring RecoveryB 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.

A B C

DE

F

2. SET_PRED A

1. Retransmit TOKEN0. Transmit TOKEN

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 13

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.

1

1

7

7

5

5

44

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 14

UC Berkeley WOW

Solutions: Unique Priority of TokenBased 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 address generation sequence …

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 15

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

11

1

61

2

2

6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 16

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

21

1

66

2

2

6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 17

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

22

1

66

6

2

6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 18

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

62

2

66

6

2

6

At next stepDelete token with generation sequence number 2 since the next node has seen token with generation sequence number 6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 19

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

66

2

66

6

6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 20

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

66

6

66

6

6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 21

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

66

6

76

6

7Token refreshed by owner

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 22

UC Berkeley WOW

Token Recovery (Multiple Tokens Resolution)

66

6

77

6

7

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 23

UC Berkeley WOW

Token Recovery (Ring Address Resolution)

66

6

76

6

6

Suppose that the owner of the token has failed

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 24

UC Berkeley WOW

Token Recovery (Ring Address Resolution)

66

6

78

6

This node detects that the owner is down and claims the token

8

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 25

UC Berkeley WOW

Token Recovery (Ring Address Resolution)

66

6

78

88

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 26

UC Berkeley WOW

Token Recovery (Ring Address Resolution)

86

6

78

8

8

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 27

UC Berkeley WOW

QOS Interface

High Priority Applications (6) Low Priority Applications (6,3)

Wireless Token Ring Protocol (10)

Register 6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 28

UC Berkeley WOW

QOS Interface

High Priority Applications (6) Low Priority Applications (6,3)

Wireless Token Ring Protocol (4)

GrantedRegister 6

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 29

UC Berkeley WOW

QOS Interface

High Priority Applications (6) Low Priority Applications (6,3)

Wireless Token Ring Protocol (4)

Granted Handler Register 3

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 30

UC Berkeley WOW

QOS Interface

High Priority Applications (6) Low Priority Applications (6,3)

Wireless Token Ring Protocol (1)

Granted

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 31

UC Berkeley WOW

WTRP Deliverables (2001)

WTRPSoftwareCore

UDP CORE

UDP Implementation

IP

API

WTRPSoftwareCore

KERNEL CORE

LINUX KERNEL Implementation

IP

Driver

WTRPSoftwareCore

SIMULATOR CORE

SIMULATOR Implementation

Channel Model

Front End

http://wow.eecs.berkeley.edu

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 32

UC Berkeley WOWUDP: Video Streaming

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 33

UC Berkeley WOWSimulation Front End

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 34

UC Berkeley WOW

A

B

A

B

A

B

1 32

Token Rotation Time Vs. Rotation

C CC

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 35

UC Berkeley WOW

Fairness

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 36

UC Berkeley WOW

Throughput Comparison With 802.11 DCF

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 37

UC Berkeley WOW

ConclusionsThe 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.

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 38

UC Berkeley WOW

ConclusionsThe 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.

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 39

UC Berkeley WOW

ConclusionsThe 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.

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 40

UC Berkeley WOW

ConclusionsThe 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.

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 41

UC Berkeley WOW

ConclusionsThe 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.

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 42

UC Berkeley WOW

ConclusionsThe 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.

July 15, 2002

SCI02 ORLANDO

Wireless Token Ring Protocol 43

UC Berkeley WOW

ConclusionsThe 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.