Download Sensor Network Routing-Wireless Networking-Lecture 08 Slides-Electrical and Computer Engineering and more Slides Wireless Networking in PDF only on Docsity!
Lecture 9
WSNs: Data Dissemination
Reading: •^
“Wireless Sensor Networks,” Chapter 12, sections 12.2-12.4.
-^
W. Heinzelman, A. Chandrakasan, and H. Balakrishnan, “An Application-Specific Protocol Architecture for Wireless Microsensor Networks,”
IEEE Trans.
on Wireless Communications, Vol. 1, No. 4, Oct. 2002, pp. 660-670.
-^
C. Intanagonwiwat et al., “Directed Diffusion: A Scalable and RobustCommunication Paradigm for Sensor Networks,”
Proc. MobiCom '00.
-^
W. Heinzelman, J. Kulik, and H. Balakrishnan, “Adaptive Protocols forInformation Dissemination in Wireless Sensor Networks,”
Proc. MobiCom ’99.
-^
D. Braginsky and D. Estrin, “Rumor Routing Algorithm for Sensor Networks,”Proc. WSNA, Sept. 2002, pp. 22-31.
Sensor Network Routing
^
Energy-efficiency even more important than in MANETs ^
“Resource”-aware, data-centric routing needed^ ^
Reduce power consumption ^
Distribute energy load (maximize network lifetime) ^
Take into account sensors’ importance to application
^
May be tightly coupled with protocols from different layers^ ^
Take advantage of data fusion opportunities ^
Cross-layer architectures
^
Types of routing needed^ ^
One-to-one: data to sink ^
Many-to-one: all sensors’ data to sink ^
One-to-many: sink commands to sensors ^
Many-to-many: data dissemination, flooding, gossiping
Data-Centric Routing
^
Aggregate data or information from data important^ ^
Individual data items not important
^
Sensor nodes themselves less important than data ^
Queries posed for specific data rather than data from a particularsensor ^
Routing exploits the requirement for aggregate data rather thanindividual data ^
Example protocols^ ^
SPIN ^
Directed Diffusion ^
Rumor Routing
Network-wide Data Dissemination
A
B^
C
D
F
E
G
H A,G,H
B,C,F
B,C,D,E
C,E,D
B,E,F,G
C,D,E,F
A,G,H
A,B,F-H^ A,G,H
A-H
B-H
B-G
A-H
B-G
A-C,E-H
A,B,F-H A-H
A-H
A-H
A-H
A-H
A-H
A-H
A-H
Problem: information dissemination
Resource Inefficiencies^
Implosion
A
B^
C
D
(a) (a)
(a) (a)
A^
B
C^
(r,s)
(q,r)
q^
s r
^
Data overlap
^
Resource blindness
What is the optimum protocol?
B
D^
E
F
C^ G
A
^
“Ideal”^
Shortest-path routes Avoids overlap Minimum energy Need global topology information
SPIN Example
B
A
DATAREQ ADVADV
ADV
ADV ADV
ADV
ADV
REQ
REQ
REQ
REQ
REQ
DATA DATA
DATA
DATA DATA
SPIN Example 2
ADV
E D
REQ
E D
DATA
E D
C ADV
E D
C
B
A
A^
Nodes with data A^
Nodes without data Nodes waiting to transmit REQ A
Directed Diffusion
^
Abstraction that tries to describe communication patternsunderlying many localized algorithms
^
Data named with attribute-value pairs
^
Nodes that want data express interests based on thepredefined attributes
^
Interests disseminated throughout network
^
Interests diffuse to correct area^
Intermediate nodes propagate interests based on the contentsof the interest E.g., if interest is for data from location (x,y), interest will bepropagated towards (x,y)
Directed Diffusion
^
Interests may be propagated to multiple neighbors forrobustness
^
Gradients set up that draw events of interest back tooriginating node^
Strength of gradient depends on quality of the routing path Application-specific meaning to a gradient ^
Interests/data propagated along routes with strong gradients^
Good routes inherently reinforced Creates low-energy routing of data ^
Data aggregation and caching performed within the network^
Further reduces node energy dissipation
Directed Diffusion Protocol
^
Sinks broadcast interest to neighbors
^
Interests are cached by neighbors
^
Gradients are set up pointing back to where interestscame from at low data rate
^
Once a source receives an interest, it routesmeasurements along gradients
^
Gradients from source to sink initially small^
Increased during reinforcement
Directed Diffusion (cont.)
Simulation Results
Rumor Routing
^
In query-based networks, different techniques forrouting data and queries^
Query flooding
^
Expensive for large query/event ratio ^
Allows for optimal reverse path setup ^
Gossiping scheme can be use to reduce overhead
^
Event Flooding^
Expensive for low query/event ratio ^
Note^
Both of them provide shortest delay paths
