Rendezvous Regions: A Scalable Architecture for Service Location and Data-Centric Storage in...

Rendezvous Regions: A Scalable Rendezvous Regions: A Scalable Architecture for Service Location Architecture for Service Location

and Data-Centric Storage in and Data-Centric Storage in Large-Scale Wireless Sensor Large-Scale Wireless Sensor

NetworksNetworks

Karim Seada, Ahmed HelmyKarim Seada, Ahmed HelmyElectrical engineering Department, University of SouElectrical engineering Department, University of Sou

thern Californiathern CaliforniaIEEE IPDPS 2004IEEE IPDPS 2004

Speaker: Hao-Chun SunSpeaker: Hao-Chun Sun

OutlineOutline

IntroductionIntroduction Related WorkRelated Work Rendezvous Regions (RR) Rendezvous Regions (RR)

ArchitectureArchitecture Performance EvaluationPerformance Evaluation ConclusionConclusion

IntroductionIntroduction

Challenges of sensor networksChallenges of sensor networks– Limited resourcesLimited resources– Extremely large number of nodesExtremely large number of nodes

Sensor networkSensor network– Application-specificApplication-specific

The tasks is sent to nodes.The tasks is sent to nodes. The data is recorded by nodes about the The data is recorded by nodes about the

environment.environment.

IntroductionIntroduction

Typical approaches for resources Typical approaches for resources discovery and data storagediscovery and data storage– Local storageLocal storage

FloodingFlooding

– External storageExternal storage High energy costHigh energy cost

– Data-centric storageData-centric storage No floodingNo flooding

sink

Access path

Related WorkRelated Work

GHT: A Geographic Hash Table for Data-GHT: A Geographic Hash Table for Data-Centric Storage (ACM WSNA 2002)Centric Storage (ACM WSNA 2002)– Sensor nodes is randomly deployment over Sensor nodes is randomly deployment over

a well-defined area.a well-defined area.– Every node is aware of its location and its Every node is aware of its location and its

one-hop neighbor location information.one-hop neighbor location information.– All nodes have the same capability.All nodes have the same capability.– Nodes are reasonably stationary and stable.Nodes are reasonably stationary and stable.


Distributed hash-tableDistributed hash-table– Put (key, value)Put (key, value)

This stores value according to the key.This stores value according to the key. key: event typekey: event type

– Get (key)Get (key) This retrieves the value of the key.This retrieves the value of the key.

Distributed hash-table (DHT) over GPSRDistributed hash-table (DHT) over GPSR– GPSRGPSR

Strongly geographic routing algorithmStrongly geographic routing algorithm


Conceptions—Conceptions—– Geographic Hash Table (GHT)Geographic Hash Table (GHT)

Distributed Hash Table(DHT)

Distributed Hash Table(DHT)EventEvent

peer-to-peer lookup algorithm

peer-to-peer lookup algorithm

LocationLocation

GPSRGPSR

Home node for this event

Home node for this event

(key)

Temperature>50℃

Temperature>50℃


Distributed hash-table (DHT) over Distributed hash-table (DHT) over GPSRGPSR

sink

b

d

e

a

c

Get (type)

Key: typeKey: type

Put (type, valuec)Put (type, valuec)

Valuec

Related WorkRelated Work Disadvantages of GHTDisadvantages of GHT

– Rendezvous pointRendezvous point Requirement for location accuracyRequirement for location accuracy Not enough robust to the topology changes Not enough robust to the topology changes

caused by mobility.caused by mobility.

Motivation of this paperMotivation of this paper– High mobility environmentHigh mobility environment

More robust to the topology changes caused More robust to the topology changes caused by mobility.by mobility.

Rendezvous Regions (RR) ArchitecRendezvous Regions (RR) Architectureture

Data modelData model– Resource discoveryResource discovery

Lookup operationLookup operation

– Data storageData storage Insertion operationInsertion operation

– Ratio between lookups and insertionsRatio between lookups and insertions Large LIR (Lookup-to-Insertion)Large LIR (Lookup-to-Insertion)

ApplicationApplication– Users and object trackingUsers and object tracking– Database querying in sensor networksDatabase querying in sensor networks


Rendezvous Regions Basic Rendezvous Regions Basic conceptionconception– Using a rendezvous region instead of a Using a rendezvous region instead of a

rendezvous point.rendezvous point. Robustness for mobility.Robustness for mobility. Relaxing the requirements for exact Relaxing the requirements for exact

geographic information.geographic information.

Rendezvous point Rendezvous region

A set of eventsA set of events

A set of eventsA set of events


AssumptionsAssumptions– The network space is divided into The network space is divided into

rectangular equal-size regionsrectangular equal-size regions, where , where the size of the region is set based on the size of the region is set based on the the radio rangeradio range and and how many hops we how many hops we wantwant the region to cover. the region to cover.

– Each node has a localization mechanism Each node has a localization mechanism to detect its to detect its approximate geographic approximate geographic locationlocation and accordingly its region. and accordingly its region.

– The network is The network is connectedconnected and each and each region region has nodeshas nodes in it. in it.


Design overviewDesign overviewRR1 RR2 RR3

RR6RR5RR4

RR7 RR8 RR9

Events(keys)

Events(keys)



Region(RRi)

Region(RRi)

KSeti RRiKSeti RRi

Server electionProblem

Server electionProblem


Design overviewDesign overview– Inter-region routing schemeInter-region routing scheme

The RR scheme can built on top of any The RR scheme can built on top of any routing protocol that can route packets routing protocol that can route packets toward geographic regions.toward geographic regions.

The only requirement of the routing protocol The only requirement of the routing protocol is to maintain approximate geographic is to maintain approximate geographic information.information.

RRi RRj


Design overviewDesign overview– Intra-region routing schemeIntra-region routing scheme

Geocast—Send packets to all nodes in the regioGeocast—Send packets to all nodes in the region.n.

Anycast—Reach any node of a set of servers.Anycast—Reach any node of a set of servers. Unicast—Update data between serversUnicast—Update data between serversRRj


Design overviewDesign overview– Server electionServer election

Number of servers and storage overhead are Number of servers and storage overhead are tradeoff.tradeoff.

Servers are elected on-demand during Servers are elected on-demand during insertions.insertions. RRj

flooder

flooder

insertion

insertion

RRi

GeocastGeocast ACK

Probability PProbability P


Design overview—Insertion/LookupDesign overview—Insertion/LookupRR1 RR2 RR3

RR6RR5RR4

RR7 RR8 RR9

AnycastAnycast

insertion

insertion

S

RR1 KSet1RR2 KSet2……………RRn KSetn

RR1 KSet1RR2 KSet2……………RRn KSetn

flooder

flooder

Geocast

sinkR

flooder

flooder

KSeti RRiKSeti RRi


Design overviewDesign overview– ReplicationReplication

Several servers inside the region store the Several servers inside the region store the key and data.key and data.

– Robustness to server node failure.Robustness to server node failure.

RRj


Design overviewDesign overview– MobilityMobility

Rendezvous regionRendezvous region– Local movements of nodes and servers have negligiblLocal movements of nodes and servers have negligibl

e effect.e effect.– Robustness to mobilityRobustness to mobility

RRj

Check its region

periodically

Check its region

periodically

Server electionServer

election


Design overviewDesign overview– FailuresFailures

Server node failureServer node failure Server node mobilityServer node mobility

– Server election procedureServer election procedure Insertion operationInsertion operation MobilityMobility

– It is unlikely that independent It is unlikely that independent reasonable failures will cause all servers reasonable failures will cause all servers to vanish.to vanish.

Performance EvaluationPerformance Evaluation

Simulator: NS-2Simulator: NS-2 Number of Nodes: 100 ~ 400Number of Nodes: 100 ~ 400 Routing protocol: modified GPSR to route Routing protocol: modified GPSR to route

to regions instead of specific destinations.to regions instead of specific destinations. Radio range: 60m ~ 120mRadio range: 60m ~ 120m The rate of lookups is 2/s.The rate of lookups is 2/s. The number of retransmissions for both The number of retransmissions for both

insertion and lookup is 3.insertion and lookup is 3. The periodic check interval: 20sThe periodic check interval: 20s

Performance EvaluationPerformance Evaluation Mobility update overhead—Mobility update overhead—

Performance EvaluationPerformance Evaluation Lookups success rate—Lookups success rate—

Performance EvaluationPerformance Evaluation Lookups overhead—Lookups overhead—

Performance EvaluationPerformance Evaluation Success rate at low inaccuracy rangeSuccess rate at low inaccuracy range

——

Performance EvaluationPerformance Evaluation Success rate at high inaccuracy Success rate at high inaccuracy

range—range—

Performance EvaluationPerformance Evaluation Total message overhead (LIR=10)—Total message overhead (LIR=10)—

Performance EvaluationPerformance Evaluation Hotspot message overhead (LIR=10)Hotspot message overhead (LIR=10)

——

ConclusionConclusion This paper presents the design and This paper presents the design and

evaluation of RR, a scalable rendezvous-evaluation of RR, a scalable rendezvous-based architecture for wireless networks.based architecture for wireless networks.

The simulation results show that RR is The simulation results show that RR is scalable to large number of nodes and is scalable to large number of nodes and is highly efficient, especially in applications highly efficient, especially in applications with high lookup-to-insertion ratios.with high lookup-to-insertion ratios.

In mobile networks, RR has a significant In mobile networks, RR has a significant advantage over GHT with higher success advantage over GHT with higher success rate and much lower overhead.rate and much lower overhead.

RR is more robust to location inaccuracy RR is more robust to location inaccuracy than GHT.than GHT.

Rendezvous Regions: A Scalable Architecture for Service Location and Data-Centric Storage in...

Documents

Transcript of Rendezvous Regions: A Scalable Architecture for Service Location and Data-Centric Storage in...