1 CS 268: Lecture 24 Sensor Network Architecture (SNA) Ion Stoica Computer Science Division Department of Electrical Engineering and Computer Sciences.
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1
CS 268: Lecture 24 Sensor Network
Architecture (SNA)
Ion StoicaComputer Science Division
Department of Electrical Engineering and Computer SciencesUniversity of California, Berkeley
Berkeley, CA 94720-1776
2
Sensor Network Protocols Today
Phy
Link
Topology
Routing
Transport
Appln
RadioMetrixRFM
CC1000Bluetooth 802.15.4
eyesnordic
WooMacSMAC
TMACWiseMAC
FPS
MintRoute
ReORg
PAMAS
CGSR
DBF
MMRP
TBRPF
BMAC
DSDV
ARADSR
TORA
GSR GPSR GRAD
Ascent
SPIN
SPAN
Arrive
AODV
GAF
SchedulingResynch
Yao
Diffusion
Deluge Trickle Drip
RegionsHood
EnviroTrackTinyDB
PC
TTDD
Pico
FTSP
Obligatory David Culler Slide…
What if I want to use any two protocols together??
3
Network Model
Transit Network
Basestation
Sensor Patch
Patch Network
Base-Remote Link
Data Service
Internet
Client Data Browsingand Processing
Sensor Node
Gateway
Dense patches of sensing nodes- Many resource constrained- Non-homogeneous- Modalities, roles, HW, SW- Power, BW
Transit tier- Often specialized wireless- Provides gateways
Internet Tier- Multiple connections to infra- Deep storage, proc. Viz
SNA should not require unconstrained nodes
Should utilize unconstrained nodes to reduce burden on constrained ones
Mobility within physically embedded context
4
What is an Architecture?
Architecture is how to “organize” implementations- What interfaces are supported
- Where functionality is implemented
Architecture is the modular design of the network
Architecture is not the implementation itself
5
Internet vs Sensor Nets
Internet goals Interconnect separate networks Resilience to loss and failure Support many comm. services Accommodate variety Distributed management Cost effective Low effort attachment Resource accountability Network Architecture
Sensor Nets Resource efficiency Data centric design Deal with intermittent
connectivity Self-managed Observation, monitoring of
various environments Cost effective Scalability
6
Internet vs Sensor Nets
Internet goals Interconnect separate networks Resilience to loss and failure Support many comm. services Accommodate variety Distributed management Cost effective Low effort attachment Resource accountability Network Architecture
Sensor Nets Dense real world monitoring Resilience to loss, failure and
noise Support many applications Scale to large, small, long Cost effective Evolvable in resources Composable Security
7
Why not IP?
One or very few applications running on a sensornet vs huge number running in the Internet
Large variety of traffic patterns (most not point-to-point):- Any-to-any, many-to-one, many-to-few, one-to-many- Inneficient to impl. these patterns over point-to-point
IP does not address (well):- Resource and energy constraints- Unattended operation - Intermittent connectivity- Space embeded nodes- ...
8
A Sensor Network Architecture (SNA)
Narrow waist: Sensornets Protocol (SP)- Goals: generality and efficiency
- Position: between data-link and network layers
- Service: best-effort, single hop
- Common to both single- vs multiple-hop deployments
9
Properties of SP
SP provides mechanisms for network protocols to operate- Network protocols may introduce policy
Three key elements of SP:- Data Reception
- Data Transmission
- Neighbor Management
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Collaborative Interface
Control- Reliability Best effort to transmit the msg
- Urgency Priority mechanism
Feedback- Congestion Was the channel busy?
• Should I slow down?
- Phase Was there a better time to send?
• Decouple appl sampling from communication
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Message Reception
Message arrives from link SP dispatches Network protocols establish
- naming/addressing
- filtering
SP
Receive
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Message Transmission
Messages placed in shared message pool- All entries are a promise to send a
packet in the future Messages include
- Pointer to first packet and # of packets
- Control information: reliability and urgency
- Feedback information: congestion and phase
SP
Msg Pool
Send Receive
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Neighbor Management
SP provides a shared neighbor table- Cooperatively managed
- SP mediates interaction using table
• No policy on admission/eviction by SP
• Scheduling information
SP
Neighbor Table Msg Pool
Neighbors Send Receive
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SP
Data Link A Data Link B
SP Adaptor A SP Adaptor B
NetworkProtocol 1
PHY A PHY B
NetworkProtocol 2
NetworkProtocol 3
NetworkService
Manager
LinkE
stimator
LinkE
stimator
Neighbor Table Msg Pool
Neighbors Send Receive
SP Architecture
15
SP
Message Pool
sp_message_t
destinationmessagequantityurgentreliability
phasecongestion
address_t1st TOSMsg to send# of pkts to sendon or offon or off
adjustmenttrue or false
con
tro
lfe
edb
ack
Neighbor Table Msg Pool
Neighbor Table
2
1
NetworkLinkRequiredNeighbor
addresstime ontime offlistenquality
address_tlocal time node wakeslocal time node sleepstrue or falseestimated link quality
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SP
Msg Pool
Network Protocol
msg*
Next PacketHandler
packetsSP Message
MessageDispatch
transmit
completed
(1)
(2)
(3) (4)
(5)
(6)
1st packet
Send
insp
ect
Link Protocol
SP Message Futures
1) Submit an SP Message for Transmission
2) Message added to message pool3) SP requests the link transmit the
1st packet4) Link tells SP the transmission
completed5) SP asks protocol for next packet6) Protocol updates packet entry in
message pool
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What SP Isn’t
SP does not dictate any header fields- Messages are opaque to SP
Instead, rely on abstract data types- Can query for address, length, etc
No explicit security mechanism- Message content opaque to SP
- Link, Network, and App security can be built transparently to SP
18
Benchmarks
Minimal performance reduction in single hop- Compare to B-MAC paper
- Compare to IEEE 802.15.4
Simpler multihop/network protocol code
Power consumption
Network protocol co-existence
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Results: mica2 Throughput
0 5 10 15 200
2000
4000
6000
8000
10000
12000
14000
16000
Th
rou
gh
pu
t (kb
ps)
Nodes (n)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Pe
rce
nta
ge
of C
ha
nn
el C
ap
aci
ty
B-MACSPSP + CCSP + LPL + CCSP + LPL + CC + PhaseChannel Capacity
20
Results: mica2 Throughput
0 5 10 15 200
2000
4000
6000
8000
10000
12000
14000
16000
Th
rou
gh
pu
t (kb
ps)
Nodes (n)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Pe
rce
nta
ge
of C
ha
nn
el C
ap
aci
ty
B-MACSPSP + CCSP + LPL + CCSP + LPL + CC + PhaseChannel Capacity
21
Results: mica2 Throughput
0 5 10 15 200
2000
4000
6000
8000
10000
12000
14000
16000
Th
rou
gh
pu
t (kb
ps)
Nodes (n)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Pe
rce
nta
ge
of C
ha
nn
el C
ap
aci
ty
B-MACSPSP + CCSP + LPL + CCSP + LPL + CC + PhaseChannel Capacity
22
Results: mica2 Throughput
0 5 10 15 200
2000
4000
6000
8000
10000
12000
14000
16000
Th
rou
gh
pu
t (kb
ps)
Nodes (n)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Pe
rce
nta
ge
of C
ha
nn
el C
ap
aci
ty
B-MACSPSP + CCSP + LPL + CCSP + LPL + CC + PhaseChannel Capacity
23
Results: mica2 Throughput
0 5 10 15 200
2000
4000
6000
8000
10000
12000
14000
16000
Th
rou
gh
pu
t (kb
ps)
Nodes (n)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Pe
rce
nta
ge
of C
ha
nn
el C
ap
aci
ty
B-MACSPSP + CCSP + LPL + CCSP + LPL + CC + PhaseChannel Capacity
24
Results:Single Hop Benchmarks (802.15.4)
25
Conclusion
SNA: provide context for sharing our community work and accelerate the development and deployment of sensornet applications
Effective link abstraction, SP, allows network protocols to run efficiently on varying power management schemes
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