a performance comparison of manets routing protocols 2003

8/2/2019 A Performance Comparison of Manets Routing Protocols 2003

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A Performance Comparison of DSDV

& AODV Routing Protocols for

MANETs

Presented By : Chander Mohan, Pradeep Sharma & Monika Sharma

Email me : [email protected]


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Outline

Purpose of this work

Wired & Wireless Networks

Introduction to MANETs

Routing in MANETs

Compare Two Protocols DSDV AODV

Simulation ns extensions Protocol implementations

Simulation results


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Purpose of this work

Wireless ad-hoc networks have gained a lot ofimportance in wireless communications.

Wireless communication is established by nodes

acting as routers and transferring packets fromone to another in ad-hoc networks.

Routing in these networks is highly complex dueto moving nodes and hence many protocols have

been developed.

Table driven (DSDV) & Source on demand (AODV)strategies are compared.


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Wired & Wireless Networks

Wired Network

Connected with the help of wires

Very High Speed

Expensive to maintain

Wireless Network

Connected with the help of Radio

Frequencies

Speed is not very high due to

interference, multiple

connections.

Large coverage area

Node

1

Node

3

Node

2

Node1

Node2

Node

3


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Introduction to MANETs

Wireless network without any pre-existing

infrastructure

Dynamic nature of nodes i.e mobility

Every node act as a router

A MANET can be a standalone network or it

can be connected to external networks like(Internet)


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Example of MANET


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IEEE 802.11b (WLAN) & MANET


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Why Ad Hoc Networks?

Setting up of fixed access points and backbone infrastructureis not always viable

Infrastructure may not be present in a disaster area or war

zone

Infrastructure may not be practical for short-range radios;Bluetooth (range ~ 10m)

Ad hoc networks

Do not need backbone infrastructure support

Useful when infrastructure is absent, destroyed orimpractical


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Applications

Personal area networking cell phone, laptop

Military environment

soldiers, tanks, planes

Civilian environment taxi cab network

meeting rooms

sports stadiums

boats, small aircraft Emergency operations

search-and-rescue

policing and fire fighting


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Challenges in Mobile Environments

Limitations of the Wireless Network packet loss due to transmission errors

frequent disconnections/partitions

limited communication bandwidth

Limitations Imposed by Mobility dynamically changing topologies/routes

lack of mobility awareness by system/applications

Limitations of the Mobile Computer short battery lifetime


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Working of MANET


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Features of MANETs

Autonomous Terminal

Distributed Operation

Multi hop Routing Dynamic Topology


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Routing in MANETs

Routing is the act of moving information from

a source to a destination

Routing involves two activities

- Determining optimal routing path

- Transferring the packets


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Classification of Routing Protocols

in MANETs


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Table Driven (Proactive)

The nodes maintain a table of

routes to every destination inthe network

Keeping routes to all

destinations up-to-date, even if

they are not used, is a

disadvantage with regard to theusage of bandwidth and of

network resources

Low latency, suitable for real-

time traffic

On-demand (Reactive)

These protocols were designed

to overcome the wasted effort inmaintaining unused routes,

Routing information is acquired

only when there is a need for it

Saves energy and bandwidth

during inactivity Flooding is used for route

discovery

Significant delay might occur as a

result of route discovery


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DSDV (Destination Sequenced Distance Vector)

Protocol

Based on Bellman-Ford Routing Algorithm (BFRA)

Each node maintains a routing table which stores

next hop, cost metric towards each destination

a sequence number that is created by the destination itself

Each route is tagged with a sequence number; routes withgreater sequence numbers are preferred

When a node decides that a route is broken, it increments thesequence number of the route and advertises it with infinitemetric


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DSDV (Destination Sequenced Distance Vector)

Protocol

When X receives information from Y about a route to Z Let destination sequence number for Z at X be S(X), S(Y) is sent from Y

If S(X) > S(Y), then X ignores the routing information received from Y

If S(X) = S(Y), and cost of going through Y is smaller than the route

known to X, then X sets Y as the next hop to Z

If S(X) < S(Y), then X sets Y as the next hop to Z, and S(X) is updated to

equal S(Y)

X Y Z


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AODV (Ad Hoc On-Demand Distance Vector

Routing) Protocol

Route Requests (RREQ) are forwarded to discover a route

When a node re-broadcasts a Route Request, it sets up areverse path pointing towards the source

When the intended destination receives a Route Request, itreplies by sending a Route Reply (RREP)

Route Reply travels along the reverse path set-up when RouteRequest is forwarded


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Route Discovery in AODV

1

2

3

4

5

6

7

8

Source

Destination

Propagation of Route Request (RREQ) packet


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In case of broken links

Node monitors the link status of next hop in

active routes

Route Error packets (RERR) is used to notify

other nodes if link is broken

Nodes remove corresponding route entry

after hearing RERR


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Route Discovery in AODV

1

2

3

4

5

6

7

8

Source

Destination

Path taken by Route Reply (RREP) packet


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Simulation

Network Simulator ns-2.34 based on- Otcl (an object oriented extension of Tcl)

- C++


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Simulation

Scenario

Tcl Script

C++Implementation

1 2

set ns_ [new Simulator]

set node_(0) [$ns_ node]set node_(1) [$ns_ node]

class MobileNode : public Node{

friend class PositionHandler;

public:MobileNode();

}


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What we need in one simulation?

Appearance: the whole topology view of sensor networkor mobile network

The position of nodes: (x, y, z) coordinate

The movement parameters

Starting time

To what direction

Speed

Internal work: which nodes are the sources? what are the

connections? and using what kind of connection? Drive the simulation: What about the configuration

network components on sensor node? Where to give outthe simulation results? How to organize a simulationprocess?


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Simulation Parameters


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Simulation Scenario


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Packet Drop in AODV & DSDV at 70 sec

AODV

DSDV


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Results & Discussion

AODV DSDV


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Throughput Analysis


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Conclusion

DSDV routing protocol consume more

bandwidth, because of frequent broadcasting

of updates

AODV is much better than DSDV as it results in

less overhead and more bandwidth


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THANK YOU

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a performance comparison of manets routing protocols 2003

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