Mobile Ad-Hoc Mobile Ad-Hoc Networks(MANET)Networks(MANET)

SEMINAR SEMINAR

BY BY

Vinit pareekVinit pareek

B.TECH(ECE-8B.TECH(ECE-8thth sem.) sem.)

FINAL YEAR(S.B.C.E.T)FINAL YEAR(S.B.C.E.T)

OrganizationOrganization

Introduction to Mobile Ad hoc networks Introduction to Mobile Ad hoc networks (MANETs)(MANETs)

Routing in MANETsRouting in MANETs Virtual Backbone RoutingVirtual Backbone Routing SecuritySecurity Performance measuresPerformance measures

Introducing MANETsIntroducing MANETs

Cellular NetworksCellular Networks Infrastructure dependentInfrastructure dependent High setup costsHigh setup costs Large setup timeLarge setup time ReliableReliable

MANETsMANETs(RFC2051 of IETF)(RFC2051 of IETF) No infrastructure is usedNo infrastructure is used Fast setup Fast setup Flexible and dynamicFlexible and dynamic

Applications of MANETsApplications of MANETs

Some motivating applications:Some motivating applications: Casual conferencingCasual conferencing

low set-up time, cost preferredlow set-up time, cost preferred

Battlefield operations/disaster reliefBattlefield operations/disaster relief infrastructure unavailableinfrastructure unavailable

Personal area networkingPersonal area networking devices around the home/officedevices around the home/office

Cellular networks are not preferred.Cellular networks are not preferred.

Mobile Ad hoc Mobile Ad hoc NetworksNetworks

First ad-hoc network was dev. By ARPA called First ad-hoc network was dev. By ARPA called “Packet “Packet

Radio Networks” had 138 mobile nodes.Radio Networks” had 138 mobile nodes. multi-hop routes between nodes.multi-hop routes between nodes.

Characteristics of Characteristics of MANETsMANETs

Dynamic topologyDynamic topology links formed and broken with mobilitylinks formed and broken with mobility

uni-directional links and bi-directional linksuni-directional links and bi-directional links Constrained resourcesConstrained resources

battery powerbattery power wireless transmitter rangewireless transmitter range

Network partitionsNetwork partitions

A B AB

Dynamic Source Routing Dynamic Source Routing (DSR)(DSR)

Routing is through source routingRouting is through source routing complete path with each packetcomplete path with each packet

Route discoveryRoute discovery flooding flooding RREQRREQ till a node replies till a node replies

Route maintainance Route maintainance explicit link breakage notificationexplicit link breakage notification

Mobility of a node can break routes passing through it.Mobility of a node can break routes passing through it.

Route DiscoveryRoute Discovery A route between two nodes is A route between two nodes is

found by sending an Route found by sending an Route RequestRequest

Route Request builds a source Route Request builds a source route on every path through the route on every path through the networknetwork

First Route Request to arrive is First Route Request to arrive is accepted; target responds on accepted; target responds on that path and tells initiator what that path and tells initiator what the source route isthe source route is

Source route is used on Source route is used on subsequent data trafficsubsequent data traffic

B

H I J

GFE

D

A

C

K

Detected Source Route:(A, B, F, J, K)

Destination Sequenced Destination Sequenced Distance Vector (DSDV)Distance Vector (DSDV)

Modified Distance Vector protocolModified Distance Vector protocol periodic DV updatesperiodic DV updates

High frequency of DV updatesHigh frequency of DV updates topology is dynamictopology is dynamic

Does not scale wellDoes not scale well size of DV updates increasesize of DV updates increase high routing overheadshigh routing overheads

Clusterhead Gateway Clusterhead Gateway Switch Routing (CGSR)Switch Routing (CGSR)

A clusterhead is able to control a group of ad-hoc A clusterhead is able to control a group of ad-hoc hostshosts

Each node maintains 2 tables:Each node maintains 2 tables:1.1. A cluster member table, containing the cluster head for A cluster member table, containing the cluster head for

each destination nodeeach destination node2.2. A DV-routing table, containing the next hop to the A DV-routing table, containing the next hop to the

destinationdestination

Clusterhead Gateway Clusterhead Gateway Switch Routing (CGSR)Switch Routing (CGSR)

Associativity-Based Routing Associativity-Based Routing (ABR)(ABR)

Free from loops, deadlock, and packet Free from loops, deadlock, and packet duplicates, and defines a new routing metric for duplicates, and defines a new routing metric for ad-hoc mobile networksad-hoc mobile networks

Hello message exchange periodically b/w Hello message exchange periodically b/w neighboursneighbours

With the temporal stability and the associativity With the temporal stability and the associativity table the nodes are able to classify each table the nodes are able to classify each neighbor link as stable or unstable.neighbor link as stable or unstable.

Associativity-Based Routing Associativity-Based Routing (ABR)(ABR)

Signal Stability Routing Signal Stability Routing (SSR)(SSR)

Based on ABRBased on ABR It selects routes based on signal strength.It selects routes based on signal strength. Can be dynamic or staticCan be dynamic or static Advantages:Advantages: to select strong connection to select strong connection

leads to fewer route reconstruction.leads to fewer route reconstruction. Drawbacks:Drawbacks: long delay since intermediate long delay since intermediate

nodes can’t answer the path (unlike nodes can’t answer the path (unlike AODV, DSR)AODV, DSR)

Security in MANETSecurity in MANET

Access controlAccess control KerberosKerberos Cryptographyic schemes Cryptographyic schemes Packet retransmissionPacket retransmission Intrusion Detection System(IDS)Intrusion Detection System(IDS)

Performance IssuesPerformance Issues

Network sizeNetwork size Route acqusition timeRoute acqusition time ConnectivityConnectivity Average no. of data transmittedAverage no. of data transmitted Fraction of sleeping nodesFraction of sleeping nodes Routing protocol usedRouting protocol used

The Dynamic Virtual BackboneThe Dynamic Virtual Backbone

The dynamic virtual backbone is a concept The dynamic virtual backbone is a concept wherein a set of relatively stable routes are wherein a set of relatively stable routes are formed despite nodes being mobile.formed despite nodes being mobile.

a possible way is to abstract mobility through a possible way is to abstract mobility through aggregationaggregation

ReferencesReferences

Wikipedia.orgWikipedia.org

RFC document of IETF.RFC document of IETF.

Mobile Computing By Johan SchillarMobile Computing By Johan Schillar

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