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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
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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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Conti
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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5.Node C receives RREQ.
Makes a reverse route entry for Sdest=S, nexthop=A, hopcount=2
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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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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
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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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