SHARP: A Hybrid Adaptive Routing Protocol for

Mobile Ad Hoc Networks

Venugopalan Ramasubramanian, Zygmunt J. Haas, and Emin Gun sirer

ACM MobiHoc 2003

Speaker ： ChiChih Wu

OutlineOutline• Introduction• Overview of SHARP• SHARP Routing Protocols• Simulations• Conclusions

IntroductionIntroduction• Ad hoc routing protocols

– Proactive protocols• DSDV

– Reactive protocols• AODV• TORA

– Hybrid protocols

IntroductionIntroduction• Proactive protocols

– Advantage• good reliability• Low latency through frequent dissemination

of routing information

– Disadvantage• high overhead

IntroductionIntroduction• Reactive protocols

– Advantage• Low routing overhead

– Disadvantage• Increase latency due to on-demand route

discovery and route maintenance

Overview of SHARPOverview of SHARP• SHARP Routing Protocol

– Proactive Zone– All nodes not in the proactive zone use reactive

routing protocols to establish routes to that node

– Making some nodes more popular than others

Overview of SHARPOverview of SHARP

Proactive Zone

Reactive RoutingProtocol

Overview of SHARPOverview of SHARP• Proactive Zone

– By increasing the radius, SHARP can decrease the loss rate and variance in delay, but will pay more in packet overhead to maintain routes in a large zone

– By decreasing the radius, SHARP can reduce routing overhead, as fewer nodes need to be proactively updated; however, it may pay more in delay jitter and experience higher loss rates

SHARP Routing ProtocolsSHARP Routing Protocols• Proactive Routing Component

– Destination Sequenced Distance Vector (DSDV)

– Temporally Ordered Routing Algorithm (TORA)

• Reactive Routing Component– Ad-hoc On-demand Distance Vector

(AODV)

SHARP Routing ProtocolsSHARP Routing Protocols• DSDV

– Table driven

dest next metric …

A A 0

B B 1

C B 2

dest next metric …

A A 1

B B 0

C B 1

A CB

dest next metric …

A B 2

B B 1

C C 0

SHARP Routing ProtocolsSHARP Routing Protocols• TORA

s

d

3

3

2

2

2

1

1

0

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height

SHARP Routing ProtocolsSHARP Routing Protocols

SHARP Routing ProtocolsSHARP Routing Protocols• TORA

s

d

SHARP Routing ProtocolsSHARP Routing Protocols• Proactive Routing Component

– Building and maintaining a directed acyclic graph (DAG ) rooted at the destination

SHARP Routing ProtocolsSHARP Routing Protocols• Reactive Routing Protocols

d

s

s

d

d

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s

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Source

Destination

SimulationsSimulations• 600 nodes

– 3000m X 3000m– 8 packets per second– 256 bytes per packet

• 200 nodes– 1700m X 1700m– 2 packets per second– 256 bytes per packet

• Velocities ranged between 0 m/s and 20 m/s

SimulationsSimulations Mobility fraction

SimulationsSimulations

SimulationsSimulations

SimulationsSimulations

ConclusionsConclusions• SHARP could be used to minimize

packet overhead, to bound loss rate, and to control delay jitter

• SHARP achieves performance that is better than each one of its concomitant purely reactive and purely proactive protocols across a wide range of network conditions

THANK YOUTHANK YOU