1. A Talk on Mobile Ad hoc Networks (Manets)
Dr. O.B.V. RAMANAIAH
PROFESSOR, CSE Dept,
JNTUH College of Engineering,
HYDERABAD –

2. OUTLINE Brief Intro to Manets Routing Options CONCLUSION Unicast,
Broadcast,
Multicast &
Geocast
CONCLUSION
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3. Types of Mobile Networks
Two Types
- Conventional (with Infrastructure)
- MANETs (without any Infrastructure)
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4. Mobile Ad Hoc Networks (MANETs) (1)
MH2
MH4
Asymmetric link
MH3
MH5
Symmetric link
MH7
MH1
MH6
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5. Mobile Ad Hoc Networks (MANETs) (1)
MH2
Physical Mobility of MH2
MH2
MH4
Asymmetric link
MH3
MH5
Symmetric link
MH7
MH1
MH6
Mobility Causes Topology and Hence Route Changes
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6. Decreased Dependence on Infrastructure
Why Ad Hoc Networks ?
Ease of Deployment
Speed of Deployment
Decreased Dependence on Infrastructure
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7. Many Applications … Military Environments Civilian Environments
Emergency Operation
Search-and-Rescue
PAN
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8. Unicast, Broadcast, Multicast, Geocast, Anycast
Besides…
Webcast
Telecast
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9. Unicast Routing Approaches
Topology-Based
Depends on the information about existing links to forward packets
Position-Based
Sender uses location service to determine the position of Destination Node
(Physical location of each or some nodes determine their own position through GPS or some other positioning technique)
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10. Topology Based Protocols
Proactive Protocols
Traditional distributed shortest-path protocols
Maintain routes between every host pair at all times
Based on periodic updates; High routing overhead
Example: DSDV (Destination Sequenced Distance Vector)
Reactive Protocols
Determine route as and when needed
Source initiates Route Discovery
Example: DSR (Dynamic Source Routing)
Hybrid Protocols
Adaptive; Combination of proactive and reactive
Example : ZRP (Zone Routing Protocol)
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11. Proactive Routing Approaches Destination-Sequenced Distance-Vector (DSDV) Protocol
Distance Vector Routing = DVR = Bellman-Ford Algorithm
Proactive version for Manets DSDV
Each MH
Broadcasts routing updates periodically
Maintains a routing table for all possible destinations
Sequence Numbers enable the MHs to distinguish stale routes from new ones
How to decide whether the Update is Current or Stale?
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12. DSDV … MH X takes the following steps:
If S(X) > S(Y), then X ignores the routing information received from Y
If S(Y) = S(X), 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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13. Dynamic Source Routing (DSR)
When node S wants to send a packet to node D, but does not know a route to D, node S initiates a Route Discovery
Source node S floods Route Request (RREQ)
Each node Appends Own Identifier when forwarding RREQ
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14. Route Discovery in DSR (1)
Represents a node that has received RREQ for D from S B A S E F H J D C G I K Z M N L
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15. Route Discovery in DSR (2)B A S E F H J D C G I K
Represents transmission of RREQ Z Y
Broadcast transmission M N L
[S]
[X,Y] Represents list of identifiers appended to RREQ
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16. Route Discovery in DSR (3)B A S E F H J D C G I K
Node H receives packet RREQ from two neighbors:
potential for collision Z Y M N L
[S,E]
[S,C]
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17. Route Discovery in DSR (4)B A S E F H J D C G I K
Node C receives RREQ from G and H, but does not forward
it again, because node C has already forwarded RREQ once Z Y M N L
[S,C,G]
[S,E,F]
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18. Route Discovery in DSR (5)B A S E F H J D C G I K Z Y M
Nodes J and K both broadcast RREQ to node D Since nodes J and K are hidden from each other, their transmissions may collide N L
[S,C,G,K]
[S,E,F,J]
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19. Route Discovery in DSR (6)B A S E F H J D C G I K Z Y
Node D does not forward RREQ, because node D is the intended target of the route discovery M N L
[S,E,F,J,M]
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20. Route Reply in DSR (2) S D Route Reply (RREP) is Unicast to S by D B AF H J D C G I K Z Y M N L
RREP [S,E,F,J,D]
Represents RREP control message
Route Reply (RREP) is Unicast to S by D
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21. Hybrid Routing Approaches … Zone Routing Protocol (ZRP)
All nodes within hop distance at most d from a node X are said to be in the Routing Zone of X.
IARP: Proactively maintain routes to all nodes within the source node’s own zone
Neighbour Discovery Protocol (NDP)
IERP: Use an on-demand protocol (similar to DSR or AODV) to determine routes to outside zone
Bordercast Routing Protocol (BRP)
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22. Zone Routing Protocol (ZRP) (2)S L K G H I J A B C D E
All nodes except L are in the Routing Zone of S with Radius = 2
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23. Zone Routing Protocol (ZRP) (3) Zone Radius, K = 2F B D
S performs Route
Discovery for D
Denotes route request
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24. Zone Routing Protocol (ZRP) (5) Zone Radius, K = 2F B D
S performs route
discovery for D
Denotes route reply
E knows route from E to D,
so route request need not be
forwarded to D from E
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25. Zone Routing Protocol (ZRP) (4) Zone Radius, K = 2F B D
S routes DATA to D
Denotes route taken by Data
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26. Some More Protocols … PROACTIVE AODV Fisheye State Routing REACTIVE
Link Reversal Routing
TORA
PROACTIVE
WRP (Wireless RP)
OLSR (Optimized LSR)
MPR (Multipoint Relays)
Hybrid
Fisheye State Routing
Landmark (LANMAR)
CBRP
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27. Textbook (Cordeiro & Agrawal)
1/e, Cambridge Pubs, Rs 450/-
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28. Questions ?