Kamoun Ad Hoc Network 2010 Final

Ad-hoc Networks

Farouk Kamoun

Esprit

Module d'ouverture

2009-2010

Self-Defending Software 2

WLan Wi-Fi Alliance Wi-Fi Alliance : Organization that groups the major

wireless market players in the world Its Objective:

promote Wi-Fi as an international standard for wireless networks

Garantee interoperability of Wi-Fi (Wireless Fidelity) products

Garantee security in Wi-Fi (WPA & WPA2) Garantee QoS (Wi-Fi MultiMedia)

Self-Defending Software 3

Wlan infrastructure mode (ESS)

BSS

STATION

Point d’accès

STATION

STATION

ESS

distribution Systèm

BSS

STATION

Point d’accès

STATION

STATION

Main Charactéristics :

• Network ID

(SSID)

• Transmission Canal

• Security Mechanisms

• Topology

Internet

44Self-Defending SoftwareSelf-Defending Software

Channel Access:CSMA/CAChannel Access:CSMA/CA

Instead of Collision Detection we look for: Instead of Collision Detection we look for: Collision Avoidance (CA)Collision Avoidance (CA)

CSMA/CA is based on :CSMA/CA is based on :

Listening the channelListening the channelPhysical Carrier SensePhysical Carrier Sense

Virtual Carrier SenseVirtual Carrier SenseReservation Mechanism (RTS/CTS)

Network Allocation Vector (NAV)

Timers IFSTimers IFS

Backoff algorithmBackoff algorithm

Positive AcknowledgementsPositive Acknowledgements


ArchitectureArchitecture


ad hoc mode (IBSS)ad hoc mode (IBSS)

IBSS

STATION

STATION

STATION

STATION

Main Charactéristics :

• Network ID

(SSID)

• Transmission Channel

• Security Mechanisms

• Topology

77 Convergence des protocoles de routage dans les réseaux Ad hoc

Ad Hoc Networks CharacteristicsAd Hoc Networks Characteristics

Ad hoc network :

Require new Routing Protocols taking into account ad hoc net characteristics:

No infrastructure

Mobility

Low bandwidth

Energy limitation


ApplicationsApplications

Conferencing

Home networking

Community networking

Military Combat networking

Relief organization (secours)

Catastrophy management

Specialized ad-hoc nets:Mesh Networks

Sensor networks

Vehicule Ad-hoc neworks : VANET


Environnement PhysiqueEnvironnement Physique

Notion de Connexion

Problème d'Interférence

Problème du Nœud Caché


Routing ProtocolsRouting Protocols

Proactive routing protocols: DSDV, OLSR

Reactive routing protocols: AODV, DSR

Hybrid routing protocols: ZRP, cluster-based

MMDV (Multipath and MPR based AODV) developed in the

Cristal laboratory


Routing Protocols

Routing Protocols: 3 classes

Proactive Hybrid

Distance Vector

Link State

ZRP DSRAODVTORADYMODSDV OLSR

TBRPFFSRSTAR

Reactive/ on demand


Proactive Protocols Proactive Protocols

Routes are established in advance

May send packets immediately

But too much overhead

Deux major methods:

Distance Vector:Next node to destination

Example: DSDV

Link State Network Topology

Example: OLSR, TBRPF


DSDVDSDVPreserve simplicity of RIP protocol

Each Node keeps a Routing table with entries to all destinations:

destination node, distance (in hops), next node, sequence number, life-time..

Periodical exchange of routing information (Distance vectors) with neighbors:

Possible optimization by sending reduced tables containing changes and sometimes the whole table

Table Update:Upon reception of a distance vector from a neighbour, each node compares for each destination:

If new seq number is higher then update routing entryIf new seq number is equal to existing seq number update entry only if new distance is smaller than existing oneIf new seq number is smaller than existing one then discard this information (no change)

Update period: because of mobility there are frequent changes in topology -- Small update period --large overhead


DSDV: Change of TopologyDSDV: Change of Topology

If a Node Detect That a Link with a Neighbor is Lost ( at level 2 with hello messages of Beacon or at level 3 no reception of routing Tables)

It sets hop distance to infinity (large number) to that entry and to all entries that use that node as next hop

A new sequence number is set: old-sequence number of that entry + 1 (this is the only time that a node is allowed to change the Seq number of another node

Broadcast the RT

Note that that if there is a good path for some nodes it will be recovered through the exchange of tables


DSDV: ImprovementsDSDV: Improvements

For large networks: use 2 type or routing information

Full dump: Full Routing Table

Incremental: Carry only Changes that occured since last full dump

Send Full Dump less frequently and use in between Incremental routing information

ConclusionSimple routing algorithm

Not efficient


OLSROLSROptimized Link State Routing Protocol [CLA03]

Project Hipercom, INRIA

T. Clausen, P. Jacquet (RFC 3626) October 2003

Proactive, Link State

Each node must have full information on Topology

Each node must send routing information to all nodes Flooding

Multipoint Relays (MPR) toSelection of subset of neighbors to forward « routing » packets

reduce flooding


OLSR - MPROLSR - MPR

Simple flooding flooding through MPRs

MPR

Several copies


OLSR – MSOLSR – MS

MS : Multipoint Relay Selector

MS(N) : Set of nodes that chose N as their MPR.

MS(3) = {…, 4, …}MS(6) = {…, 4, …}

14

3 5

2

6

7

1

4

35

2

6

7

Example: MPR(4) = { 3, 6 }


Choice of MPRsChoice of MPRs

Algorithm

1/ Select all neighbors (1-hop) that are unique neighbors to 2-hop neighbors

2/ Eeliminate the 2-hop neighbors connected to the set of MPR nodes

3/Find among the neighbors the node that allow to reach the largest number of 2-hop nodes and add it to the set of MPRs and eliminate the 2-hop nodes reached by the new selected MPR

4/ Repeat step 3 until all 2-hop neigbors are eliminated (covered)


OLSR – MPROLSR – MPRMPR : Multipoint Relay

Each node N selects a set of nodes MPR(N) among his

neighbors. This Set must cover all nodes at 2 hops from N

Neighbors that do not belong to MPR(N) process the control

packets coming from N but do not forward them

How would a neighbor of N know that it belongs or not to MPR(N)?

Keep a List MS (Multipoint Relay Selector)


OLSR – MessagesOLSR – Messages

Messages transmitted periodically:

HELLO (every 2seconds)

Contain list of neighbors as well as the types of links (Symetric,

Asymetric).

Allow to select MPRs.

Used to determine neighbor table

TC :Topology Control (every 2seconds)

Allow to declare MPR’s in the whole network

Transmitted by MPRs

Used to determine topology tables

MID

Multi interface


OLSR –OLSR –HELLOHELLO

A B

A doesn’t hear B. Hello packet of A is empty

B hears A. Hello packet of B contains A with status: asymetric

A hears B and knows that B can hear him. Hello packet of A contains B with status: symetric

B hears A and knows that A can hear him. Hello packet of B contains A with status: symetric

Hello(N)={List of Neighbors, type of link (sym, asym, MPR or lost)}


OLSR –OLSR –HELLOHELLO

Neighbor discovery

HELLO messages are not relayed (TTL=1)

Using the list of neighbors received in HELLO messages, each

node N can determine the list of neighbors at 2 hops and

then determine its list of MPR(N).

14

3 52

6

7

For node 4:V(1) = {2}V(3) = {2,5}V(5) = {3,6}V(6) = {5,7}

MPR(4) ={3,6}


OLSR –OLSR – Heuristic to determine Heuristic to determine MPR nodesMPR nodes

Step 1:MPR(4)={}

Add neighbors that uniquely connect to 2 hop neighbors of 4

MPR(4)={6}

Step 2:While there exists 2 hop neighbors not covered by nodes in MPR(4), add the neighbor that covers the largest number of 2 hop neighbors

MPR(4)={6,3}

14

3 52

6

7

Neighbor

Number of 2

Hop Nodes

5 0

3 1

1 1


OLSR –OLSR – TC TC

TC (Topology Control) messages are periodically

broadcasted in the entire network

Only MPR nodes (i.e. MS not empty) broadcast TC

messages :

List of MS (partial information on links)

Sequence Number (to avoid using obsolete information)

All nodes N process TC messages

Using TC messages, each node determines a topological

table That will allow it to compute the routing table


OLSR – TablesOLSR – Tables

Each Node maintains:

Neighbor data base

Table: direct neighbors

Table: 2 hop neighbors.

List of MPRs.

List of MPR Selectors (MS)

Topology Base Topology Table

Routing Table T_dest T_last T_seq T_time

Destination Adress

adress of an MPR of the destination

Sequence

Number

Time-life of this information.

R_dest R_next R_dist R_if_id

destination adress

Next node to the destination

distance in hops interface of local node


Update of Routing Table RTUpdate of Routing Table RT

RT is computed from Table of Neighbors and Topology TableTopology Table is created from the received Topology Control MessagesAll Nodes selected as MPRs broadcast periodically their MPS Selector (MS) Update RT if there is a change in Neighbors or in the TT:1/ Delete all entries from RT2/ Add to RT all neighbors with symetric link status

R_Next = R_dest, R_dist=13/Repeat 4 begin with R_current-dist=1, stop if no more nodes to add4/ For each entry in TT which verifes:

It does not belong to RT

T_Last of that node is a destination in RT with distance = R_current-dist

Then create an entry for that node in RT such that:R_Dest = T_Dest (of that Node)

R_Next = T_Last

R_Dist = R_current-dist + 1Increase R_current-dist by one

5/ Delete entries not used in TT


OLSR – ExampleOLSR – Example

A

BB

DD

CC

EE

GG

FF

II

HH

EE

Hello(E ; - ; -)

Hello(B; A; sym; D; mpr; E;assy)

Hello(E; F; mpr; G; mpr; D;mpr;B;sym)

MS(D)={E;C,A,B}

MS(E)={D;B;F;G}TC(E)={D;B;F;G}

TR(A)

TC(D)={E;C,A,B}

A

Assume that E just connects to the network at this instant E sends an empty Hello message to all its neighbors

T_des T_last T_seq T_time

D E

B E

F E

G E

E D

C D

… … … ...

TT(A)

R_des R_next

R_dist R_if_id

B B 1

D D 1

C D 2

E D 2

F D 3

G D 3

…

MPR(E)={D,F,G}


OLSR – SynthesisOLSR – Synthesis

Based on MPR concept( Multipoint Relays)

Optimization of diffusion overhead

Diffusion of packets through MPRs

Reduce Overhead

A control packet contains only a subset of neighbors

less Overhead

Nodes know a partial topology

Computed roads are optimal

Routes are immediatly available


OLSR - DrawbacksOLSR - Drawbacks

Control Messages sent periodically HELLO_INTERVAL= 2 sec

TC_INTERVAL= 5 sec

doesn’t react well to node mobility, solution? Increase frequency of hello messages increase overhead risk of congestion

Decrease of periodicity of Hello messages weak adaptation to topology changes List of MPRs obsolete erroneous control information

Fast-OLSR Dynamic OLSR (fast OLSR) (node in one of 2 states fast or normal))


Reactive ProtocolsReactive Protocols

Routes are established on DemandNo control traffic if routes are not used

But packet is slowed down if route doesn’t exist!

Two major techniques:

Source Routing: the source indicates the path to be followed by a packet to reach a destination (DSR)

The source forwards the packet to the next node towards the destination (AODV)


AODV – Presentation AODV – Presentation

Ad hoc On-Demand Distance Vector

C. Perkins, E. Belding-Royer et S. Das (RFC 3561) july 2003

Reactive, distance vector

Each Node keeps a Routing table with entries to some destinations:dest node, next node, distance (in hops), dest sequence No , life-time, precursors

Upon arrival of a packet:If entry for destination exists on the table (and not obsolete) then send packet

If no entry then establish a road to destination

Route Establishment

Route Request, RREQ (Broadcast) with an ID to avoid duplications

Route Reply, RREP (unicast)

Route Error,RERR (unicast) in case of link failure on the established path


AODV – Example 1 AODV – Example 1

A

BB

DD

CC

EE

JJ

FF

HH

II

RREQ

RREQ

RREQ

Des N.H Mét

F B 3

RREP

RREP RREP

Dest

N.H Dist A

FF

Broadcast of RREQ’s

RREQ

Process of route discoveryResponse to a route discovery

RREQRREQ

RREQ


AODV – Example 2 AODV – Example 2

A

BB

DD

CC

EE

JJ

FF

HH

II

RREQ

RREQ

RREQ

F B 3

A A 1 E

F E 2 A

A B 2 F

F F 1 AA E 3

RREP

RREP RREP

A A 1 F

A B 2

A

FF

X

RERR

RERR

A E 3

RREQ broadcast

RREQ will be ignored by nodes if {adresse ip,Broadcast_ID} already exists in table of

« Broadcast_ID »

Assume all tables are empty

Routing Table

Destination

Next node

Distance in Hops

List of precursors

…

RREQ


AODV – Recap AODV – Recap

Advantages: expectSmaller routing tables

Better Adaptation to topology changes

Drawbacks:RREQ Flooding

Improvements:AODV-PA:

Path Accumulation

AODV multipath:Multiple Paths

Drawbacks:RREQ Flooding

Improvements:AODV-PA:

Path Accumulation

AODV multipath:Multiple Paths

BB

DD

CC

EE

JJ

FF

HH

II

A


DSR – PresentationDSR – Presentation

Dynamic Source Routing Protocol: David Johnson et al. (INTERNET−DRAFT)

The source specifies the entire path to the destination in the packet header

Each Node keeps a Cash but not a Routing tableUpon arrival of a packet:

If path for destination exists in the Cash (and not obsolete) then send packet with path in headerIf no entry then establish a path to destination

Route EstablishmentRoute Request, RREQ (Broadcast) with an ID to avoid duplicationsRoute Reply, RREP (unicast)Route Error, RERR (unicast) in case of link failure on the established path

RREQ’s cause largeOverheads


DSR – Example 1DSR – Example 1

A

BB

DD

CC

EE

JJ

FF

HH

II

RREQ[A]

RREQ[A;D]

RREQ[A;B]

RREQ[A;D;E]

Chemin Mét

F-E-D-A 3A

FFChemin Mét

A-D-E-F 3

RREP[F-E-D-A]RREP[F-E-D-A]RREP[F-E-D-A]

Path Accumulation

Process of route discoveryResponse to a route discovery

RREQ[A;D;E;J]RREQ[A;D;E;J;I]

RREQ[A;D;E;J;I;H]

Chemin Mét

F-E-D-A 3

H-I-J-E-D-A 5


DSR – Example 2DSR – Example 2

Chemin Mét

A-D-E-J-I-H-F

6

A-D-E-F 3

A

BB

DD

CC

EE

JJ

FF

HH

II

RREQ(A)

RREQ(A;D)

RREQ(A;B)

RREQ(A;D;E)

RREQ(A;D;C) Chemin Mét

J-I-H-F 3

J-E-D-A 3

Chemin Mét

F-E-D-A 3A

FF

RREP(F-H-I-J-E-D-A)

RREP(F-H-I-J-E-D-A)RREP(F-H-I-J-E-D-A)

Path Dist

A-D-E-J-I-H-F

6

RREP(F-E-D-A)RREP(F-E-D-A)RREP(F-E-D-A)

RREQ is ignored if :

{adress ip, RREQ_ID} exists in list of RREQs recently received}.

the address of the current node exists in the path of the RREQ.

If a node has a path to the destination in its cash then it concatenates the path it obtained with the one in the cash and sends a reply to the source.

Node chooses shortest path to destination


DSR – RecapDSR – Recap

Advantages:Easy to implement

Multiple Paths

Drawbacks:Agressive usage of cashes

Path validity

Cash Pollution

Improvements:DSR*-DR:

Does not allow intermediate nodes to reply using information in their cash

DSR*:Introduce Path lifetime

BB

DD

CC

EE

JJ

FF

HH

II

A


Important Routing Important Routing FeaturesFeatures

Features Protocol Characteristic

MPR flooding OLSRMinimize flooding

Detection of high mobilityFast-OLSR

Adapt to topology changes

Path Accumulation DSRMore routing information

Multiple Routes DSR/TBRPFAdapt to topology changes


Work at Cristal Lab: AODV OptimisationWork at Cristal Lab: AODV OptimisationApprochApproch

AODV+MPROptimization of RREQ flooding

AODV+MPR Dynamic (fast OlSR feature)MPR with detection of high mobility

AODV+PAPath Accumulation

AODV multi cheminMultiple Paths


AODV + MPRAODV + MPR

Modification of AODV Hello Messages :

Processing of Hello Messages :Update Neighbor Table

Update Routing Table Protocole hybride

Selection of MPR list Périodic


AODV + « Dynamic » MPRAODV + « Dynamic » MPR

Detection of high mobility:Changes in neigbor table (Fast-OLSR)

Threshold=1/5

If a node detects a high mobility :Changes to Rapid State

Increase frequecy of Hello messages

Reduce time of computation of MPR List


AODV+PAAODV+PA

Path Accumulation

Add sequence of traversed nodes in routing tables

Modify the structure of RREQ and RREP

Add Adresses of intermediary nodes

Processing of RREQ and RREP

Update routing table

Add entries to intermediary nodes


AODV multiple pathAODV multiple path

Multiple path :Maintain 2 « disjoint » paths

Minimize probability of path failures

Minimize number of nodes in common for the 2 pathsAODV Multipath Protocol

Add JointCount (JC) field to RREP messages

Each common node increases JC

Threshold <=2/5 to retain a path

S A B C D

BB

DD

CC

EE

JJ

FF

HH

II

A0

1

11


Performance EvaluationPerformance EvaluationPerformance Variables:

Packet delivery rate (received packets / transmitted packets)

End-to end delay (Response time)

Routing overheadNormalized overhead (Routing packets generated/data packets received)

Routing Charge (Kbit/s)

Implementation of the protocoles under NS-2 simulator

Run simulation Measurement at steady state

Compute confidence intervalls

Use batch mean method to stop simulation


Simulation Scenarios Simulation Scenarios

Nombre de nœuds

Aire (m2)

Densité (nœud / m2)

Modèle de mobilité

Temps de pause (s)

Vitesse max (m/s)

scénario 1

50

1000 * 750

scénario 2

100

1500 * 1000

Scénario 3

100

700 * 700

1 / 15000

Random waypoint

30

0 - 20

1 / 15000

Random waypoint

30

0 - 20

1 / 4900

Random waypoint

30

10

Nombre de connexion CBR

2020 10-100

Débit 4 paquets/s 4 paquets/s 4 paquets/s

Capacité des liens 2 Mb/s 2 Mb/s 2 Mb/s


Delivery RateDelivery Ratescénario 2

100

1500 * 1000

1 / 15000

Random waypoint

30

0 - 20

20

4 paquets/s

2 Mb/s

Scénario 3

100

700 * 700

1 / 4900

Random waypoint

30

10

10-100

4 paquets/s

2 Mb/s

65

70

75

80

85

90

95

100

0 5 10 15 20

Pac

ket

deliv

ery

frac

tion

(%)

Max speed (m/s)

AODVAODV+MPR

AODV+DynMPRAODV+PA

Multipath AODV

35

40

45

50

55

60

65

70

0 5 10 15 20

Pac

ket

deliv

ery

frac

tion

(%)

Max speed (m/s)

AODVAODV+MPR

AODV+DynMPRAODV+PA

Multipath AODV

10

20

30

40

50

60

70

80

90

100

10 20 30 40 50 60 70 80 90 100

Pac

ket

deliv

ery

frac

tion

(%)

Number of connections

AODVAODV+MPR

AODV+DynMPRAODV+PA

Multipath AODV

scénario 1

50

1000 * 750

1 / 15000

Random waypoint

30

0 - 20

20

4 paquets/s

2 Mb/s

Nombre de nœuds

Aire (m2)



Temps de pause (s)

Vitesse max (m/s)


Débit de donnée

Capacité des liens


Synthesis of resultsSynthesis of results

Delivery rate:

2 best features Dynamic MPR Multiple path

MMDV (add 2 features to AODV)

Low speed Low traffic

load

High speed High traffic load

AODV+PA C C C C

AODV+MPR B B C C

AODV+DynMPRA A B B

AODV multi

cheminC C A A

40

45

50

55

60

65

70

0 5 10 15 20

Pac

ket

deliv

ery

frac

tion

(%)

Max speed (m/s)

AODV+DynMPRMultipath AODV


MMDVMMDV

MMDV: Multipath and MPR based AODV

Hybrid ProtocolProactive Phase :

Periodic update sof routes to neighbours at up to 2 hops (hello messages)

Periodic computation of MPRs

Reactive Phase :Establishment of a new Path (RREQ/RREP)

Compute « disjoint » paths

Two zonesZone within 2 hops (proactive routing)

Zone beyond 2 hops (reactive routing)


MMDV- ExampleMMDV- Example

BB

DD

CC

EE

JJ

FF

HH

II

A RERR

KK


Delivery RateDelivery Rate

75

80

85

90

95

100

0 5 10 15 20

Pac

ket

deliv

ery

frac

tion

(%)

Max speed (m/s)

AODV+DynMPRAODV multipath

MMAODV

40

45

50

55

60

65

70

0 5 10 15 20

Pac

ket

deliv

ery

frac

tion

(%)

Max speed (m/s)


MMAODV

20

30

40

50

60

70

80

90

100

10 20 30 40 50 60 70 80 90 100

Pac

ket

deliv

ery

frac

tion

(%)



MMAODV

scénario 2

100

1500 * 1000

1 / 15000

Random waypoint

30

0 - 20

20

4 paquets/s

2 Mb/s

Scénario 3

100

700 * 700

1 / 4900

Random waypoint

30

10

10-100

4 paquets/s

2 Mb/s

scénario 1

50

1000 * 750

1 / 15000

Random waypoint

30

0 - 20

20

4 paquets/s

2 Mb/s

Nombre de nœuds

Aire (m2)



Temps de pause (s)

Vitesse max (m/s)


Débit de donnée

Capacité des liens


Routing Overhead (load)Routing Overhead (load)scénario 2

100

1500 * 1000

1 / 15000

Random waypoint

30

0 - 20

20

4 paquets/s

2 Mb/s

Scénario 3

100

700 * 700

1 / 4900

Random waypoint

30

10

10-100

4 paquets/s

2 Mb/s

scénario 1

50

1000 * 750

1 / 15000

Random waypoint

30

0 - 20

20

4 paquets/s

2 Mb/s

Nombre de nœuds

Aire (m2)



Temps de pause (s)

Vitesse max (m/s)


Débit de donnée

Capacité des liens

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

10 20 30 40 50 60 70 80 90 100

Nor

mal

ized

rou

ting

load



MMAODV

1.2

1.4

1.6

1.8

2

2.2

2.4

2.6

0 5 10 15 20

Nor

mal

ized

rou

ting

load

Max speed (m/s)


MMAODV

1.6

1.8

2

2.2

2.4

2.6

2.8

3

3.2

3.4

0 5 10 15 20

Nor

mal

ized

rou

ting

load

Max speed (m/s)


MMAODV


MMDV vs AODVMMDV vs AODV Nombre de nœuds

Aire (m2)



Temps de pause (s)

Vitesse max (m/s)

scénario 1

50

1000 * 750

scénario 2

100

1500 * 1000

1 / 15000

Random waypoint

30

0 - 20

1 / 15000

Random waypoint

30

0 - 20


2020

Débit de donnée 4 paquets/s 4 paquets/s

Capacité des liens 2 Mb/s 2 Mb/s

30

40

50

60

70

80

90

100

0 5 10 15 20

Tau

x d

e re

ussi

te (

%)

Vitesse max (m/s)

MMDV (scenario1)AODV (scenario1)MMDV (scenario2)AODV (scenario2)

Nombre de nœuds

Aire (m2)



Temps de pause (s)

Vitesse max (m/s)

Scénario 3

100

700 * 700

1 / 4900

Random waypoint

30

10


10-100

Débit de donnée 4 paquets/s

Capacité des liens 2 Mb/s

10

20

30

40

50

60

70

80

90

100

10 20 30 40 50 60 70 80 90 100

Tau

x d

e re

ussi

te (

%)

Nombre max de connexions

MMDV (scenario3)AODV (scenario3)


Conclusion Conclusion

Many routing protocolsMMDV is interesting but

4 are in the final standardization process

More work is required at the network level: autoconfiguration (addressing schemes)

More work is required at the transport level:UDP, TCP, others?

Quality of Service

Security

Killer Application

Real deployments

Mesh Networks look more promissing!!

Kamoun Ad Hoc Network 2010 Final

Documents

Transcript of Kamoun Ad Hoc Network 2010 Final