Mobility-Based Routing Mobility-Based Routing Overheads Management in Overheads Management in

RW RW AdAd h hoc Networksoc Networks

Mobility-Based Routing Mobility-Based Routing Overheads Management in Overheads Management in

RW RW AdAd h hoc Networksoc Networks

Gikaru, Wilfred GithukaGikaru, Wilfred Githuka

Dissertation Talk – Muenster 2004Technische Universität DresdenFakultät InformatikInstitut für Systemarchitektur

RO Management in RW Ad hoc Networks 2Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Agenda• Introduction and Overview• Motivation• Approach• Related work• Node level RO management• Network level RO management• Implementations and Simulations• Evaluation and Analysis • Summary and conclusions• Next step and Future work

RO Management in RW Ad hoc Networks 3Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Introduction and Overview

• Ad Hoc Networks– RWAdhoc Networks– Routing in Ad Hoc Networks

• Protocol Classes• Mobility and reconfiguration

• Performance of Routing Protocols– Throughput – Packet Delivery Ratio– Delay

Introduction and OverviewMotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations Simulations and analysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 4Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Motivation• Justification

– Why do this piece of research and who needs it ?– Contribution to research? – What is expected or has been accomplished?

• Research gap– Effects of Routing Overheads on Network/protocol

Performance (both Node and network level)– Importance of Node location and motion

parameters

• Evidence– Network traffic analysis (from literature)

•Introduction and Overview

MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

Table 1

ProtocolRequests Replies Error Routing Data

DSR 25 56 18 89 11AODV 89 6 4 84 14

Bandwidth utility of RO at routing and mac layers

Routing layer Mac layer

RO Management in RW Ad hoc Networks 5Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Approach

• Making use of Node parameters• 1st approach: Reduction of neighbourhood

discovery broadcasts (e.g. hello messages) – Node level – Link Availability forecast

• 2nd approach: Reduction of route establishment broadcasts (e.g. route request broadcasts) – Network Level

• Cone flooding• Destination Search method

•Introduction and Overview•Motivation

ApproachRelated workNode level RO managementNetwork level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 6Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Related work

• Performance analysis is a hot reaserach topic – pinpoints deterioration of overheads but no concrete solution

offered instead, new protocols are suggested for better results at a cost

• Previous work favour specific protocol classes – on-demand reduce RO by maintaining only needed routes (aodv,

tora etc) or maintaining multiple route (dsr)– proactive reduce RO using forwarding groups (olsr, gpsr etc) - no

balance is offered in either cases– Location based (lar, geocast etc) protocols do not address Node

level overhead reduction, moreover they do not consider destination‘s mobility and likely to miss target with higher margin

• My approach offers suggestions to manage the Routing Overheads (RO) with a general approach common to most protocols – pulling together research issues with one focus– Handles RO management both at Node and Network levels

•Introduction and Overview•Motivation•Approach

Related work•Node level RO management•Network level Ro management•Implementations•Simulations and Analysis •Evaluation•Summary and conclusions•Next step and Future work

RO Management in RW Ad hoc Networks 7Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Node level RO Management

• Link availability forecast– Relative motion of nodes (the basic Idea)

nC1

m

nm

Rn,m

Fig 1. Relative movement of two nodes n and m

•Introduction and Overview•MotivationApproachRelated work

Node level RO managementNetwork level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

Rn

Rm

C2

n’

m’

RO Management in RW Ad hoc Networks 8Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Link availability forecast.

contd

Check if Node is dormant

No

Yes

Unsafe Link ?

Get current Host status

Yes

NoNode Active

Hello timer expires

Link Status Timer Expires

Load information in “Hello

Message” packet

Update neighbours list with current parameters

Reset Hello Timer to last

Update plus Intv

Broadcast Hello

Reset Link status timer

Reset Hello timer

Figure 2: Algorithm for Link Availability forecast

•Introduction and Overview•MotivationApproachRelated work

Node level RO managementNetwork level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 9Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Network level RO Management

• Two approaches suggested.– Cone flooding method.

• Limiting broadcast to a cone towards last known motion parameters of destination

– Destination search reverse zone coverage method.• Maintaining routes longer and using them to identify

possible location of destination again based on its motion history.

•Introduction and Overview•MotivationApproachRelated workNode level RO management

Network level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 10Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Cone flooding method

I(xI,yI,zI)

rI

r

R

•Introduction and Overview•MotivationApproachRelated workNode level RO management

Network level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

Figure 3. Search direction field of node d from node S

x

y

z

S(xs,ys,zs)

d(xd,yd,zd)

H

RO Management in RW Ad hoc Networks 11Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Cone flooding - algorithm

Load packet with Sid, Did, Sloc, Dloc, Sav.speed, Dav.speed etc

Broadcast packet

Figure 4 The Schematic diagram of the scheme

•Introduction and Overview•MotivationApproachRelated workNode level RO management

Network level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future workN

Y

Y

Y

N N

Receive packet

Is Nod

e Dst?

Compute r and rI

Generate a Reply

RI > r ?

Newer inf of dest ?

Forward packet towards dest

Drop pckt

RO Management in RW Ad hoc Networks 12Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Destination search reverse zone coverage method

Figure 5. Checking existence of I in search Region

I(xI, yI)

l

rrI

R-r c

a

b = H

•Introduction and Overview•MotivationApproachRelated workNode level RO management

Network level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

Z2

S(xs,ys)

Z1

D(xD,yD)

RO Management in RW Ad hoc Networks 13Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Destination search - algorithm

Packet Received by Destination

Destination changes Source and Dest fields and inserts

its motion parameters

Destination replaces packet header with Route Request header and sends the packet

towards the Source

•Introduction and Overview•MotivationApproachRelated workNode level RO management

Network level RO managementImplementationsSimulations and Analysis EvaluationSummary and conclusionsNext step and Future work

Drop pckt

Y

Y

Y

N

Y N

N

N

Node in Z1

?

Record Packets inf and forward it.

Perform Test 2

Node in

Z2?

Is Node Dest?

Intermediate Node receives Request packet

Node performs Test 1

TTL expire

d?

Initiate Route Reply followed by Inf

Packets

N Y

Load packet with Sid, Did, Sloc, Dloc, Sav.speed, Dav.speed etc

Send DestSearch Packet

Old Rt

Availbl

Use Nornal Flooding

Figure 6

RO Management in RW Ad hoc Networks 14Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Implementations

• The ns-2 Simulation tool (free ware) used– Suitability: time based and suitable for Mobile Ad

Hocs– Real world situations – (under improvement)

• Other tools in the field– GloMoSim - free ware, OpNet - commercial, QualNet

- commercial

• All available tools are tools under development– Updates of the tool and existing protocols at times

results to contradicting simulation results that require a lot of adjustments (time consuming)

– Newer versions at times not compatible with simulation platform

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO management

ImplementationsSimulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 15Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Simulations and Analysis

• Basic results and comparisons with existing algorithms– Performance of Routing Protocols (DSR and

AODV-hello)– Comparing of AODV-hello with AODV-Link

Avaialbility

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 16Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

General performance of Routing Protocols (DSR and AODV)

Figure 8(a) Average delay against Number of nodes

0,00000

0,40000

0,80000

1,20000

1,60000

2,00000

2,40000

Number of Nodes

Av

era

ge

de

lay

(s

ec

)

AODV

DSR

Average delay deteriorates with increase in number of nodes (more conjestion)

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 17Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

General performance of Routing Protocols (DSR and AODV) contd.

Figure 8(b) Packets delivery ratio with nodes number

0,40000

0,50000

0,60000

0,70000

0,80000

0,90000

1,00000

1,10000

Number of nodes

De

live

ry r

ati

o

AODV

DSR

Packet Delivery ratio reduces with increase in number of nodes in the network (conjestion)

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 18Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

General performance of Routing Protocols (DSR and AODV) contd

Figure 8(c) Throughput against Number of Nodes

0,00005,0000

10,000015,000020,000025,000030,000035,0000

Number of Nodes

Th

rou

gh

pu

t (p

ck

ts/s

ec

)

AODV

DSR

Throughput increase due to more routes to destination available as more nodes are in the network

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 19Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

General performance of Routing Protocols (DSR and AODV)

Routing Overheads with Number of Nodes

0

2000

4000

6000

8000

10000

12000

14000

Number of nodes

Ro

utin

g O

verh

ead

s (p

ckts

)

AODV

DSR

Figure 8(d)

With increase in number of nodes, more traffic is generated dominated by Routing packets

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 20Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Number of nodes against Routing Overheads

02000400060008000

100001200014000

Number of nodes

Ro

utin

g O

verh

ead

(P

acke

ts)

AODV

AODV_LA

Comparing AODV-hello with AODV- Link Avaialbility

Figure 9(a)

Protocol performance with increase in number of nodes at a rate of 8 pckts per second and mobility of 20 m/s

Routing Overhead reduced at higher Number of Nodes . At nn=50/40 we have 20% reduction and about 33% at nn=80/64.

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 21Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Figure 9(b) Number of Nodes against Average Delay

0,00000

0,50000

1,00000

1,50000

2,00000

2,50000

Number of nodes

Ave

rag

e d

elay

(sec

)

AODV

AODV_LA

Comparing AODV-hello with AODV- Link Avaialbility

Improvement in Average Delay at high numer of nodes. From 50 and above, delay reduction of about 20% achieved

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 22Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Figure 9(c) Nodes/source number against Delivery ratio

0,00000

0,20000

0,40000

0,60000

0,80000

1,00000

1,20000

Nodes/source

Del

iver

y R

atio

AODV

AODV_LA

Comparing AODV-hello with AODV- Link Avaialbility

No Significant gain in Delivery Ratio. For fewer nodes, higher delay introduced by computations for transmission decision

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 23Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Node density against throughput

0,00005,0000

10,000015,000020,000025,000030,000035,0000

Node density (nodes)

thro

ughp

ut (p

ckts

/sec

)

AODV

AODV_LA

Figure 9 (d)

Comparing AODV-hello with AODV- Link Avaialbility contd.

No significant gain in throughput for increase in Node number. However with increase in rate, throughput improved by about 25% (see fig 10a).

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 24Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Vairation of throughput with Rate

0

5.000

10.000

15.000

20.000

25.000

30.000

35.000

40.000

45.000

4 8 12 16 20 24 32 40 48 56 64 72 80 88

Rate

thro

ughp

ut (p

ckts

/uni

t tim

e) AODVAODV_LA

Figure 10 (a)

Comparing AODV-hello with AODV- Link Avaialbility contd.

Better throughput with reduced Routing Overhead at higher traffic rates for 100 nodes

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 25Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Comparing AODV-hello with AODV- Link Avaialbility contd.

Variation of Routing Overhead with Rate

0

10000

20000

30000

40000

50000

4 8 12 16 20 24 32 40 48 56 64 72 80 88

Rate (Pckts/sec)

Ove

rhea

d (p

ckts

)

AODV

AODV_LA

Figure 10 (b)

Significant drop in Routing Overhead for 100 nodes

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and AnalysisEvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 26Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Evaluation• Observations

– Most of the bandwidth is occupied by routing packets (data occupies less than 20 % in tested protocols

– Delivery ratio affected by dropping of packets due to • Unavailability of routes due to premature deletion of routes (aodv)• Luck of fresh routes (dsr)• Dropping from filled up if-queues (bandwidth shortage, congestion

etc) as a result of increased RO

• Gains in the suggested approaches.– Link Availability algorithm brings about reduction in

neighbourhood broadcasts (hello messages)– Reduction of Routing Overheads leads to:

• Improvement in protocol performance (throughput, Average delay and delivery ratio)

• Requirements and restrictions of approach– Only has effect after nodes have knowledge of the initial

neighbourhood – communication has to be established first– Available tools don’t allow for complete real world simulations

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations

Simulations and Analysis

EvaluationSummary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 27Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Summary and Conclusions

• Suggested schemes handle Routing Overhead management both at Node and Network level

• Motion history plays an important role in aproximating possible target location

• Network congestion (resultig from RO) is the main factor affecting network/protocol performance

• Schemes results to less overheads and higher availablility of bandwidth

• Performance improvement as a result of less congested network

• Scheme suitable a cross section of protocols• Further improvements expected from the second

scheme

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementationsSimulations and Analysis Evaluation

Summary and conclusionsNext step and Future work

RO Management in RW Ad hoc Networks 28Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Next Step and Future work

• What happens next:– Completion of simulation and Evaluation of second

scheme• Action plan for follow-up:

– Simulation of Network level RO reduction– Evaluation of results– Revisit Node level RO reduction scheme– General evaluations– Final Conclusions

• Optimisation of routes• Simulation Tests with nodes having independent

properties and variables – transmission radii– varying speeds, – unpredicted change in direction– varying and unpredicted rates of transmission etc

•Introduction and Overview•MotivationApproachRelated workNode level RO managementNetwork level RO managementImplementations Simulations and Analysis EvaluationSummary and conclusions

Next step and Future workEND

RO Management in RW Ad hoc Networks 29Technische Universität DresdenFakultät InformatikInstitute für Systemarchitektur

Thankyou !

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