aodv-BA seminar

7/30/2019 aodv-BA seminar

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A NEW AODV ROUTING PROTOCOL IN

MANET

RASHMI S

MTECH CSE


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TYPES OF WIRELESS NETWORKS

o Infrastructure based

(E.g. : wireless LAN )

Infrastructure-lessNetwork(E.g.: Mobile Ad hoc NETwork

MANET)


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CATEGORIZATIONOF AD-HOC ROUTING

PROTOCOLS


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AD-HOC ON DEMAND DISTANCE

VECTOR

Route discovery

Route maintenance

Local connectivity managementHello Messages


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AODV- ROUTEDISCOVERY

When a node wishes to send a packet to some

destination

It checks its routing table to determine if it has a

current route to the destination1. If Yes, forwards the packet to next hop node

2. If No, it initiates a route discovery process

RREQ packet contains source nodes IP address,

source nodes current sequence number, destination IPaddress, destination sequence number.

Broadcasting is done via Flooding


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Represents node that has received the packet P

Represents that connected nodes are within

each others transmission range

FLOODING FOR CONTROL DELIVERY

PACKETS-EXAMPLE


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Represent transmission of packet P

Conti


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Conti


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AODV- ROUTEDISCOVERY

Once an intermediate node receives a RREQ, the nodesets up a reverse route entry for the source node in its

route table.

In order to respond to RREQ a node should have in its

route table:1. Unexpired entry for the destination

2. Seq. number of destination at least as great as in RREQ

o the node responds to RREQ by sending a RREP back

using unicasting and not flooding to the source usingreverse path.


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AODV Route Discovery - Example

1.Node S needs a route to D.2.Creates a route request(RREQ).

Enters Ds IP address, sequence number, Ss IP address,

sequence number, hopcount.


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3.Node S broadcasts RREQ to its neighbors.

4.Node A receives RREQ.Makes a reverse route entry for S.

dest=S, nexthop=S, hopcount=1.

It has no routes to D, so it rebroadcasts RREQ


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Conti

5.Node C receives RREQ.

Makes a reverse route entry for Sdest=S, nexthop=A, hopcount=2


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Conti

C creates a Route Reply(RREP)

Enters Ds IP address, sequence number, Ss IP address,hopcount to D =1

Unicast RREP to A


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RREP contains

If RREP is being sent by destination.

The RREP will also contain the.

If RREP is sent by an intermediate node. RREP will contain the

RREP (ROUTE REPLY)


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When an intermediate node receives the RREP, it sets up

a forward path entry to the destination in its route table

Forward path entry contains

To obtain its distance to destination i.e. hop-count, anode increments its distance by 1

If route is not used within the life time, its deleted.

FORWARD PATH SETUP


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Conti

Node A receives RREP

Makes a forward route entry to Ddest=D, nexthop=C, hopcount=2

Unicast RREP to S


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Node S receives RREP

Makes a forward route entry to Ddest=D, nexthop =A, hopcount = 3


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AODV-DATA DELIVERY

Sends data packet on route to D


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ROUTE MAINTENANCE

A neighbor of node X is considered active for a routing

table entry if the neighbor sent a packet within

active_route_timeout interval.

If a source node moves, a new route discovery process is

initiated.

If intermediate nodes or the destination move ,

a) The next hop links break resulting in link failures.

b) Routing tables are updated for the link failures.

c) All active neighbors are informed by RERR message.


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RERR is initiated by the node upstream of the break

Its propagated to all the affected destinations

RERR lists all the nodes affected by the link failure -> Nodes

that were using the link to route messages

When a node receives an RERR, it marks its route to thedestination as invalid -> Setting distance to the destination as

infinity in the route table

When a source node receives an RRER, it can reinitiate

the route discovery

Conti


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LINK FAILURE DETECTION

Hello messages: Neighboring nodes periodically

exchange hello message

Absence of hello message is used as an indication of link

failure

Alternatively, failure to receive several MAC-level

acknowledgements may be used as an indication of linkfailure


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AD-HOC ON DEMAND DISTANCE

VECTOR-BREAK AVOIDANCE

Detection of a Danger of a Link Break

1. Received Radio

2. Overlap of Routes

3. Battery

4. Density


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RECEIVED RADIO

Pr= Pt.Gt.Gr.ht2.hr2dA.L

Pt = Transmitted power

Gt = Antenna gain

ht = Height of antenna

L =Loss factor


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OVERLAP OF ROUTES

oThere is a certain intermediate node on several active routes,

the transmission delay increases by the traffic loads and also the

battery of the node is quickly consumed.

oThe node receives data packets from several source nodes and

the number of received data packets per a second is more thanthe average of number of received data packets, it detects the

danger of the link break.


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BATTERY


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DENSITY

Number of neighbor nodes around intermediate node

increases, density rises.

Number of Hello packets received approximates to

number of neighbor node = HELLO_COUNT.

HELLO_COUNT > threshold


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ALGORITHM OF AVOIDING ROUTE

BREAKS

3


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ALGORITHM OF AVOIDING ROUTEBREAKS

5


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CONCLUSION

It is the algorithm in which each intermediate node on an

active route detects the danger of the link break to the

upstream node based on four elements of the received

radio, the overlap of routes, the battery and the density

and route breaks are avoided by reestablishing a newroute with proposal algorithm before route breaks.


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REFERENCES

1. Ian D.Chakeres and Elizabeth M. Belding-

Royer. ADHOC ROUTING PROTOCOL DESIGN

Proceedings of the International Workshop on Wireless

Ad Hoc Networking (WWAN), Tokyo, Japan.

2. Routing Protocols in Mobile Ad-hoc Networks,

Krishna Gorantala, Umea University Department of

Computing Science ,Sweden


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THANK YOU


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Documents

aodv-BA seminar