1
Fault Tolerant Energy Aware Data Dissemination
Protocol in Sensor Networks, in DSN 04

• ICS280
• Lee, Kyoungwoo

2
SPMS

• Khanna, DSN04 Fault Tolerant Energy Aware Data
  Dissemination Protocol
• G. Khanna, S. Bagchi, and Y. Wu
• Dependable Computing Systems Lab at Electrical
  and Computer Engineering in Purdue Univ.
• Fault Tolerant Energy Aware Data Dissemination
  Protocol in Sensor Networks, in DSN 04

3
SPMS - Overview

• Motivation
• Battery-powered sensor nodes
• Data implosion in sensor networks ? meta-data
  negotiation from SPIN (Sensor Protocols for
  Information via Negotiation)
• Prone to link and node failures
• Problem
• How to disseminate data reducing
  energy-consumption and end-to-end delay in the
  face of node and link failures
• Solution
• Each node maintains routes in the zone
• Data transfer in multiple hops using the lowest
  energy level
• Contribution
• Resilient to node and link failures
• Lower overall delay
• Energy efficient data dissemination protocol

4
SPMS Protocol
zone of S

• Initial phase
• Zone Neighbors nodes which lie within a nodes
  zone
• Zone the region that a node can reach at the
  maximum power level
• Maintain a routing table for each of its zone
  neighbors
• Meta-data exchange phase
• Broadcast ADV (Advertise) to zone neighbors
• Send REQ (Request) to the source through the
  shortest path
• Directly to the source in SPIN and who is next
  hop neighbor in SPMS
• Indirectly to the source through multiple hops
• Data dissemination phase
• Transmit DATA to the destination in exactly the
  same manner as the received REQ
• Direct form the source to the destination if they
  are next hop neighbors
• Otherwise through multi-hop communication

A
2
Zone radius with Max Tx Power
B
2
S
5
1
3
C
D
1
1
F
Routing Table of S
Dest Cost Next Hop Neighbor
A 2 Yes
B 2 Yes
C 1 Yes
D 3 No
F 2 No
5
SPIN vs. SPMS
C,D, F are interested in DATA and no failure

• SPIN
• S broadcasts ADV
• C,D, F sends REQ to S
• S sends DATA to C,D, F
• SPMS
• S broadcasts ADV
• D F check routing table
• D F start TADV waiting for F C to send ADV of
  the same data
• C sends REQ to S
• S sends DATA to C
• C broadcasts ADV
• F cancels TADV and starts TDAT
• D resets TADV
• F sends REQ to C
• C sends DATA to F
• F broadcasts ADV
• D cancels TADV and starts TDAT
• D sends REQ to F

A
2
B
2
DATA
3
S
1
ADV
1
5
3
1
ADV
REQ
DATA
2
REQ
3
2
C
D
1
REQ
REQ
4
5
8
1
F
ADV
7
6
ADV
DATA
9
DATA
zone of S

• Claim SPMS is better than SPIN in terms of
  energy delay
• Multi-hop communication with varying transmit
  power levels can reduce energy since E?d2
• Reducing power level of transmission can cause a
  smaller level of MAC layer contention

6
SPMS Protocol for Fault Tolerance

• Main Idea
• Maintain alternate node in the routing table
• PRONE Primary Originator Node
• First choice node for requesting data from
• SCONE Secondary Originator Node
• Second choice to be used in case the PRONE is
  unreachable
• Algorithm
• Update PRONE and SCONE if closer node broadcasts
  ADV
• Send REQ to PRONE with timer
• Send REQ to SCONE if timer expires
• SPMS can tolerate
• Failure of the source node after its data has
  been received by any of its neighbor nodes
• Failure of any intermediate node

7
SPMS Fault Tolerance

• CASE 1 F fails before broadcasting ADV
• S broadcasts ADV
• D F check routing table and update PRONE and
  SCONE
• D F start TADV waiting for F C to send ADV of
  the same data
• C sends REQ to S
• S sends DATA to C
• C broadcasts ADV
• F cancels TADV and starts TDAT
• D resets TADV and updates PRONE and SCONE
• F may send or not REQ to C
• C may send or not DATA to F
• F can not broadcast ADV
• TADV of D expires
• TDAT of D starts
• D sends REQ to C through F
• TDAT of D expires since F fails
• D sends REQ to C (PRONE) directly using higher
  Transmit Power
• C sends DATA to D directly

C,F, D interested in DATA and F fails
zone of S
A
2
B
2
S
1
5
3
1
ADV
REQ
DATA
2
Routing Table of D
9
3
REQ
C
Dest Cost Next Hop Neighbor
S 3 No
C 2 No
F 1 Yes
D
1
REQ
REQ
4
5
8
1
F
ADV
7
6
ADV
DATA
10
DATA
PRONE SCONE
S S


PRONE SCONE
S S
C S

8
SPMS Fault Tolerance (cont)
C,F, D interested in DATA and F fails

• CASE 2 F fails after broadcasting ADV
• S broadcasts ADV
• D F check routing table and update PRONE and
  SCONE
• D F start TADV waiting for F C to send ADV of
  the same data
• C sends REQ to S
• S sends DATA to C
• C broadcasts ADV
• F cancels TADV and starts TDAT
• D resets TADV and updates PRONE and SCONE
• F sends REQ to C
• C sends DATA to F
• F broadcasts ADV and fails
• TDAT of D starts
• D sends REQ to F
• TDAT of D expires since F fails
• D regards F dead and TDAT for C starts
• D sends REQ to C (SCONE) directly using higher
  Transmit Power
• C sends DATA to D directly

zone of S
A
2
B
2
S
1
5
3
1
ADV
REQ
DATA
2
Routing Table of D
9
3
REQ
C
Dest Cost Next Hop Neighbor
S 3 No
C 2 No
F 1 Yes
D
1
REQ
REQ
4
5
8
1
F
ADV
7
6
ADV
DATA
10
DATA
PRONE SCONE
S S
C S

PRONE SCONE
S S
C S
F C
9
SPMS Fault Tolerance (cont)
C,F, D interested in DATA and CF fail

• CASE 3 F and C fail
• S broadcasts ADV
• D F check routing table and update PRONE and
  SCONE
• D F start TADV waiting for F C to send ADV of
  the same data
• C sends REQ to S
• S sends DATA to C
• C broadcasts ADV
• F cancels TADV and starts TDAT
• D resets TADV and updates PRONE and SCONE
• F sends REQ to C
• C sends DATA to F
• F broadcasts ADV and F C fail
• TDAT of D starts
• D sends REQ to F
• TDAT of D expires since F fails
• D regards F dead and TDAT for C starts
• D sends REQ to C (SCONE) directly using higher
  Transmit Power
• ? What if C and F all fail?

zone of S
A
2
B
2
S
1
5
3
1
ADV
REQ
DATA
2
Routing Table of D
9
3
REQ
C
Dest Cost Next Hop Neighbor
S 3 No
C 2 No
F 1 Yes
D
1
REQ
REQ
4
5
8
1
F
ADV
7
6
ADV
DATA
PRONE SCONE
F C

• SPMS keeps a pair of PRONE and SCONE ? Multiple
  SCONE can increase fault tolerance

10
SPMS Energy Analysis

• ESPIN (ADR)E1 (ADR)Er
• ESPMS kAE1 k(DR)Em k(ADR)Er

• (k-1) relay nodes from the source to the
  destination
• A size of ADV
• D size of DATA
• R size of REQ
• E1, E2, , Em
• where EigtEi1 energy consumed per transmitted
  bit corresponding to the different transmission
  power levels
• Er energy required to receive the packet

ADV
AE1
AEr
DATA
DE1
DEr
Src
Dest
1
2
3
k-1
REr
RE1
REQ
ESPIN
ESPMS
AE1
DEm, REm
AEr, DEr, REr
ADV
ADV
ADV
ADV
Src
Dest
1
2
3
k-1
REQ
REQ
DATA
DATA
11
SPMS Energy Analysis (cont)

• ESPIN (ADR)E1 (ADR)Er
• ESPMS kAE1 k(DR)Em k(ADR)Er
• Ratio of Energy (SPIN/SPMS) ESPIN/ESPMS

• (Observation)
• Higher radius of transmission indicates higher
  distance from the source to the destination
• In SPIN, the energy overhead increases
  exponentially since E?d2 but it increases
  linearly in SPMS

12
SPMS Energy Experiments

• Assumptions
• Sensor field with uniform density of nodes
• Power level 3.1622, 0.7943, 0.1995, 0.05, and
  0.0125 mW taken from Berkeley MICA2
• Distance 91.44, 45.72, 22.86, 11.28, and 5.48 m
• The maximum number of the zone is six
• Size of DATA 40 bytes
• Size of REQ and ADV 2 bytes
• All-to-all communication each node generates 10
  new packets and every node is interested in them

• (Observation)
• SPMS saves 26 42 of energy compared to SPIN
• SPMS outperforms SPIN with increases of the
  number of nodes and radius of transmission

13
SPMS - Conclusion

• Fault-Tolerance
• Maintain PRONE and SCONE at routing table
• Select alternate if node fails
• Energy-Efficiency
• Multi-hop communication since E?d2
• End-to-end delay
• Less delay due to less contention of MAC

14
SPMS - Discussion

• Single-hop vs. multi-hop transmission
• Depends on application
• Increase fault-tolerance using multiple SCONEs
• Increase sleep time and decrease delay when the
  multiple failures occur

15
" Balancing Energy Efficiency and Quality of
Aggregate Data in Sensor Networks", To Appear in
the VLDB Journal Special Issue on Data Stream
Processing, 2005
16
GaNC and TiNA

• Sharaf, VLDB05 GaNC and TiNA
• M. A. Sharaf, J. Beaver, A. Labrinidis, and P. K.
  Chrysanthis
• Dependable Computing Systems Lab at Computer
  Science in Univ. of Pittsburgh
• Balancing Energy Efficiency and Quality of
  Aggregate Data in Sensor Networks, in VLDB 05
• Propose group-aware network configuration method
  (GaNC) and a framework to use temporal coherency
  tolerances (TiNA) to provide significant energy
  savings and a negligible drop in quality of data

17
GaNC TiNA - Overview

• Motivation
• Further energy savings in the context of
  In-network aggregation
• Goal
• Reduce the size of transmitted data
• Minimize the number of transmitted messages
• Without significant QoD
• Solution
• GaNC can reduce the size of transmitted data
• TiNA can minimize the number of transmitted
  messages as well
• Contribution
• Propose enhanced network configuration scheme
• Provide a framework on top of existing in-network
  configuration

18
GaNC

• Group-Aware Network Configuration method
• Observation
• The length of messages sent depends on the number
  of groups in the routing subtree
• Idea
• Reduce the number of groups to reduce the length
  of messages
• ?Group-aware Network Configuration
• Cluster along the same path sensor nodes that
  belong to the same group
• Consider semantics of the query and properties of
  sensor nodes
• Reduce the size of transmitted data

A
B
C
Group1
Group2
A
B
C
Group2
Group2
19
TiNA

• Reduce the
• size of data

• Temporal coherency-aware In-Network Aggregation
• Goal
• Reduce the size of transmitted data
• Minimize the number of transmitted message
• Idea
• Exploit temporal correlation in streams of sensor
  readings
• Suppress insignificant readings
• Potentially allow nodes to switch to sleep mode
• Work on top of existing in-network aggregation
• Introduce TOLERANCE for temporal coherency
  tolerance

A
C
B
Group1
Group2

• Old 20
• New 25
• If TOLERANCE 10,
• Transmit New
• because (25-20)/21 gt 0.1

D

• Old 20
• New 21
• If TOLERANCE 10,
• dont Transmit New
• because (21-20)/21 lt 0.1

• Reduce the number
• of messages

20
Synchronization in TAG

• TAG
• Divide a given DURATION into Communication Slots
• Duration of each Communication Slot DURATION/d
• where d number of slots maximum depth of
  routing tree
• Provide a query result every Epoch DURATION
• During a given Communication Slot, one level (A)
  sending and another level (B) listening
• At the next Communication Slot, A goes to sleep
  mode and B sending (C may be listening)

A
B
d (depth) 3
C
D
1
2
3
A
Listening
Sleep
Sleep
B
Listening
Sending
Sleep
C
Listening
Sending
Sleep
D
Sending
Sleep
Sleep
21
Synchronization in Cougar

• Cougar
• Pragmatic approach
• Algorithm
• In a certain round, A adds C to its waiting list
  if A receives data from C
• In the following rounds, A waits to hear from all
  nodes in the waiting list
• To prevent indefinite waiting, each node
  transmits reading or notification
• Reduce response time for uncongested network

waiting_list B ? B,C
A
C
B
22
Network Configuration Method

• First-Head-From Network Configuration
• Based on network proximity
• Algorithm
• Root sensor prepares query msg with query spec.
  Ls and broadcasts
• Sensor i receives msg sets LiLs1
• Sensor i sets PiIds, then sets LsLi IdsIdi
• Steps 2) 3) repeated

• Group-aware Network Configuration
• Keep members of the same group within same path
• Algorithm
• Root prepares query msg with query spec. Ls, Gs
  and broadcasts
• i receives msg sets LiLs1
• i sets PiIds PGiGs, then sets LsLi , IdsId,
  Gs Gi
• i continues to listen
• Tie-breaker conditions to select better parent
• Steps 2) to 5) repeated

• Main Difference GaNC can switch to a better
  parent
• First tie-breaker the same group ID preferred
• ?same group can reduce size of msg
• Second tie-breaker the lower distance preferred
  
• ?closer parent saves tx energy

23
TiNA - algorithm

• Algorithm
• Leaf node
• Report VNEW if VNEW violates tct s.t.
  Vold-Vnew/Vnew gt tct
• Internal node
• Collect the data from children
• Compute the partial result
• Take its own reading which can be aggregated
  within a group already exists in the partial
  result regardless of tct
• If a new group, the reading is only added when
  violating tct
• Compares an OLD partial result with the NEW
  partial with tct 0

• Main Idea
• Use temporal correlation in a sequence of sensor
  readings by suppressing insignificant readings
• TOLERANCE clause in SQL
• TOLERANCE tct (eg tct10)
• Specify the temporal coherency tolerance for the
  query
• Output filter
• Only report readings differing from the last
  reported readings by more than 10
• Information to utilize TOLERANCE
• Leaf node keep the last reported reading
• Internal last reported data from each child as
  well

24
TiNA on top of TAG

• Use the predefined communication slots for
  sending and listening
• When communication slot expires, parent checks
  and takes the last reported data for each child
  it didnt heard from
• Representation
• Circles nodes
• Arrows the flow of data
• Boxes current state
• Old last reported reading
• New current reading
• Table previously reported partial result
• Cost the size of table

• Every reading is sent from child to parent

25
TiNA on top of TAG (cont)

• New 6, Old 5 and 6-5/6 gt 0.1, thus send New
• Just add 11 to 6 and compares 17 (New) with 15
  (Old), and 17-15/17 gt 0.0, thus send New
  partial aggregate value
• 4.1-4/4.1 lt 0.1 thus suppress
• Aggregate reading to partial (17421) and
  compares it with Old (21), it suppresses since no
  change

• Algorithm
• Leaf node
• Report VNEW if VNEW violates tct s.t.
  Vold-Vnew/Vnew gt tct
• Internal node
• Collect the data from children
• Compute the partial result
• Take its own reading which can be aggregated
  within a group already exists in the partial
  result regardless of tct
• If a new group, the reading is only added when
  violating tct
• Compares an OLD partial result with the NEW
  partial with tct 0

• Less number of sent messages

26
TiNA on top of Cougar

• In Cougar, parents wait to hear from all their
  children
• Send heartbeat message notification when it can
  tolerate the quality

notify
notify

• Energy saving by sending notification
• Packet instead of data packet with
• Respect to size of message

27
TiNA with GaNC

• Presentation
• Circles nodes
• Groups Blue or not
• Boxes New data (violating tct)
• Value difference b/w New Old
• m transmission of a message
• of unit size

• Further energy saving
• Reduce total size of messages
• Reduce total number of messages

Complementary data (5 -5) cancel each other ?
save transmission
Totally 5 messages sent total size of messages
is 6
Totally 4 messages sent total size of messages
is 4
28
Evaluation by simulation

• Energy, REM (Relative Error Metric), and Response
  Time
• Energy
• 4 main activities
• Txing, Listening,
• Sampling, Processing
• Parameters for Txing Rxing
• Sensor operates 3 volts
• Data rate 40 Kbps
• Tx current 0.012 Amp
• Rx current 0.0018 Amp
• Tcost 3 V 0.012 A 1/40,000 sec 0.9
  uJoules
• Energy consumption for one bit transmission
• Rcost 3 V 0.0018 A 1 sec 0.0054 Joules
• Listening for one second
• Independent of number of messages

29
Experiments

• Sensitivity to temporal coherency tolerance
• Measure Energy, REM, response time for TiNA vs.
  for Cougar and TAG varying tct
• Tradeoff between Energy Saving and REM

TiNA with Cougar uses 56 of energy by Cougar At
tct30, only 24 but REM increases to 3.3
TiNA with TAG uses 86 of energy by TAG At
tct30, only 74.9 but REM increases to
3.7 TiNA on TAG must listen for entire assigned
time slot
30
Experiments (cont)

• Sensitivity to temporal coherency tolerance (2)
• Tradeoff between energy saving and response time
• The time to hear from all children decreases
• TiNA can send Notification instead of readings
  within tct
• For tct0 (30), the response time of TiNA on
  Cougar 60 (27) of Cougars
• The response times for TiNA on TAG are always
  same as the duration

31
Experiments Energy vs. Duration Scalability
The amount of energy increases with an
increase of Duration in TAG ?more sensors can
send readings as Dur increases
Energy consumption increases with an increase of
number of sensors in Cougar ?Energy saving
increases as network increases
32
Experiments Energy Effect of GaNC

• GaNC can save energy in sensor network for the
  most part (positive effect)
• ?GaNC can reduce the size of transmitted message

• The energy savings of GaNC over FHF decreases
• as tct increases (negative effect)
• ?Some nodes switch to parents in the same group
• (switching parents can cause more messages sent)

For larger network, positive effects outweigh
negative Effects. As tct increases, less nodes
transmitting
33
Experiments TiNA with GaNC vs. number of groups
AT the small group (eg. 5), GaNC consumes
significantly (41,38,37) ?children nodes can
select parents in the same group as them At the
large group (eg. 50), not reduce dramatically
(12, 10,9) ?less chances that children can
find parents in the same group
34
Conclusion

• GaNC (Group-aware Network Configuration)
• Consider semantics of the query and properties of
  sensor nodes
• Reduce the size of transmitted data
• TiNA (Temporal coherency-aware in-Network
  Aggregation)
• Temporal correlation in conjunction with
  in-network aggregation
• Minimize the number of transmitted messages
• Decrease the size of transmitted data
• Significant energy saving while negligible drop
  in Quality of Data
• TiNA can reduce power consumption for
  communication by up to 60 and extend the life by
  up to 270
• Additional 33 of energy can be saved by
  incorporating the GaNC with TiNA