dsr ppt

DSRDSRThe Dynamic Source Routing The Dynamic Source Routing

Protocol Protocol

Name: Name: Vikram Kr. Singh Vikram Kr. Singh

EC-09-01EC-09-01

Reg.no-0901230028Reg.no-0901230028

A

B

C

D

E

F

A—C---D---F

DSR Header packet

IntroductionIntroduction

DSR is designed for MANETsDSR is designed for MANETs

DSR doesn’t need any network infrastructures DSR doesn’t need any network infrastructures Loop free routingLoop free routing No routing information in the intermediate nodesNo routing information in the intermediate nodes

Nodes may easily cache this routing information for future useNodes may easily cache this routing information for future use

C

C’s cache

Assumption for the simulationAssumption for the simulation

All nodes in the MANETs are willing to partecipate All nodes in the MANETs are willing to partecipate fully in the DSR protocol.fully in the DSR protocol.The diameter of the MANET will often be small (5 to The diameter of the MANET will often be small (5 to 10 hops).10 hops).The speed with which node moves, is moderate with The speed with which node moves, is moderate with respect to the packet transmission latency.respect to the packet transmission latency.Nodes may be able to enable “promiscuous” receive Nodes may be able to enable “promiscuous” receive mode on their wireless network interface.mode on their wireless network interface.DSR operate with uni-directional link.DSR operate with uni-directional link.Each node selects a single IP address. Each node selects a single IP address.

Phisical layer

Data link layer

Network layer

Transport layer

Application layer

MAC

DSR protocol

DSR MechanismsDSR Mechanisms

Route discoveryRoute discoveryRoute maintenanceRoute maintenanceMechanisms “on-demand”Mechanisms “on-demand”

No periodic routing advertisementNo periodic routing advertisement No link status sensingNo link status sensing No neighbor detection packetsNo neighbor detection packets

Routes cachingRoutes caching

Basic DSR Route DiscoveryBasic DSR Route Discovery

Before…Before…

Route discovery starts…Route discovery starts…

Sender cache

No match

S RA – C - D

Basic DSR Route DiscoveryBasic DSR Route Discovery

Route reply messageRoute reply message Piggyback Piggyback

Exponential back-offExponential back-off The node must limit the Route Discovery’s rate until a The node must limit the Route Discovery’s rate until a

route reply message is receivedroute reply message is received The additional data packet sent over the limit should be The additional data packet sent over the limit should be

buffered buffered

A ERoute Reply

messageA-B-C-D

MatchNew entry

A E

No Match

New entry

A-B-C-D

New route request message with route

reply message

Subset 1 Subset 2

E

Partitoned MANET

ROUTE DISCOVERY

ROUTE DISCOVERY

I

Send Buffer

Copy

Basic DSR Route MaintenanceBasic DSR Route Maintenance

Each node transmitting the packet is responsible for Each node transmitting the packet is responsible for confirming that the packet has been received by next confirming that the packet has been received by next hop.hop.

Acknowledgement Acknowledgement By lower layer protocol MACBy lower layer protocol MAC By DSR-specific software ackBy DSR-specific software ack

Route errore messageRoute errore message

A B C D E

Route error message: C-D is broken

Additional Route Discovery Additional Route Discovery featuresfeatures

Caching overheard routing informationCaching overheard routing information In presence of uni-directional linkIn presence of uni-directional link In presence of bi-directional linkIn presence of bi-directional link

A B C D E

A—B---C---D---E

Packet to E with source route

D--ENew entry

V W X Y Z

V---W---X---Y---Z

Packet to Z with source route

X-Y-ZNew entry

C

Overhearing on bi-directional link


Replying to Route Request using cached routesReplying to Route Request using cached routes

The intermediate node must verify that the resulting The intermediate node must verify that the resulting route being returned contains no duplicate nodes listed route being returned contains no duplicate nodes listed in the route recordin the route recordInitiator

Intermediate node

ROUTE REQUEST

X

?

Route to X

Route to X

Route reply message


Preventing Route Reply stormsPreventing Route Reply storms Many Route Reply message could be send to A from the A’s Many Route Reply message could be send to A from the A’s

neighborsneighbors To avoid a possible local congestion, each nodes must wait a To avoid a possible local congestion, each nodes must wait a

variable period before sending the reply.variable period before sending the reply. Delay period d = H(h - 1 + r)Delay period d = H(h - 1 + r) Each node network interfaces works into “promiscuous” Each node network interfaces works into “promiscuous”

receive mode. receive mode.

A B

C

G

h = 1

h = 2

E

h = 3

Node C may infer that the initiator has already received a Route Reply giving

a better route because the data packet received

from B contains a value of “h” less than its h’s value


Route request Hop limitsRoute request Hop limits ““Nonpropagating” Route RequestNonpropagating” Route Request ““Propagating” Route RequestPropagating” Route Request ““Expanding ring” Expanding ring”

NonPropagating

RouteRequest

1 Hop limit

2 Hop limit

The expanding ring search approach can carry to the

average latency increasing

Support for Heterogeneous Support for Heterogeneous networks & mobile IPnetworks & mobile IP

Heteregenous networkHeteregenous network : : Different kind of devices with different interfaces.Different kind of devices with different interfaces.Possibly , multiple interfaces( short range & long range)Possibly , multiple interfaces( short range & long range)

Source routeSource routeA/1A/1→B/1→C/4→D/1→B/1→C/4→D/1

Reverse routeReverse routeD/1D/1→C/4→B/2→A/1→C/4→B/2→A/1

Internet Interconnection and MIPInternet Interconnection and MIP

DSR evaluationDSR evaluation

SimulationSimulation To analyse the behavior and performance of DSR.To analyse the behavior and performance of DSR. To Compare with other routing protocolsTo Compare with other routing protocols

Set Up:Set Up: Ad hoc of 50 mobiles nodesAd hoc of 50 mobiles nodes 15 minutes ( 900 seconds) simulation time.15 minutes ( 900 seconds) simulation time. CBR data trafficCBR data traffic 20 mobile nodes traffic sources; 4 packets/sec.20 mobile nodes traffic sources; 4 packets/sec. Random waypoint mobility model ( pause time)Random waypoint mobility model ( pause time)

ResultsResults

ConclusionConclusion

Excellent performance for routing in multi-hop ad Excellent performance for routing in multi-hop ad hoc.hoc.

Very low routing overhead.Very low routing overhead.

Able to deliver almost all originated data packets, Able to deliver almost all originated data packets, even with rapid motion of all nodes.even with rapid motion of all nodes.

dsr ppt

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