27-04-2011, 03:02 PM
PRESENTED BY:
RAKESH K.R
[attachment=12945]
INTRODUCTION
A "mobile ad hoc network" (MANET) is an autonomous system of mobile routers connected by wireless links.
Rapidly deployable, self configuring.
No need for existing infrastructure.
Wireless links.
Nodes are mobile, topology can be very dynamic.
A MANET can be a standalone network or it can be connected to external networks(Internet).
History of MANETs
FIRST GENERATION:- The first generation goes back to 1972. At the time, they were called PRNET (Packet Radio Networks).
SECOND GENERATION:- The second generation of ad-hoc networks emerged in 1980s,when the ad-hoc network systems were further enhanced and implemented as a part of the SURAN (Survivable Adaptive Radio Networks) program.
THIRD GENERATION:-
Present ad-hoc networks systems are considered as the third generation.
WIRED VS WIRELESS NETWORKS
Wired Networks:- These networks are generally connected with the help of wires and cables.
Wireless Networks:- Wireless networks use some sort of radio frequencies in air to transmit and receive data instead of using some physical cables.
FEATURES OF MANET
Dynamic Topologies.
Bandwidth-constrained, variable capacity links.
Power-constrained operations.
Limited physical security.
ROUTING PROTOCOLS FOR MANET
TABLE DRIVEN PROTOCOL
Table driven protocols are close to wired routing protocols in the manner that the routing table is built before the data has to be sent.
The disadvantage of this principle is to not be reactive to topology changes, as the tables are pre- established.
DESTINATION SEQUENCED DISTANCE VECTOR(DSDV)
ALGORITHM
With DSDV , routing table will contain
The destination address
The number of hops required to reach the destination
The new sequence number, originally stamped by the destination
On-demand style: create routes only when it is desired by the source node
When a node requires a route to a destination,
it initiates a route discovery process
Route is maintained until destination becomes unreachable, or source no longer is interested
in destination.
Ad-Hoc On-Demand Distance Vector Routing (AODV)
Builds on DSDV algorithm and the improvement is on minimising the number of required broadcasts by creating routes on an on-demand basis (not maintaining a complete list of routes)
Broadcast is used for route request
Advantages: uses bandwidth efficiently, is responsive to changes in topology, is scalable and ensures loop free routing
Drawbacks: nodes use the routing caches to reply to route queries. Result: “uncontrolled” replies and repetitive updates in hosts’ caches yet early queries cannot stop the propagation of all query messages which are flooded all over the network
APPLICATIONS OF MANET
Tactical networks
Emergency services
Home and enterprise
Networking
Education
Entertainment
USES OF MOBILE AD HOC NETWORKS
Extending Coverage
Communicating Where No Infrastructure Exists
Community Networks
PROBLEMS IN MANET
Security
Bandwidth
Energy
Asymmetric Connections
Interference
Dynamic Topology
Routing Overhead
ADVANTAGES AND DISADVANTAGES
The following are the advantages of MANETs:
They provide access to information and services regardless of geographic position.
These networks can be set up at any place and time.
These networks work without any pre-existing infrastructure.
Some of the disadvantages of MANETs are:
Limited resources. Limited physical security.
Intrinsic mutual trust vulnerable to attacks. Lack of authorization facilities.
Volatile network topology makes it hard to detect malicious nodes.
CONCLUSION
The rapid evolution in the field of mobile computing is driving a new alternative way for mobile communication, in which mobile devices form a self-creating, self organising and self-administering wireless network,called a mobile ad hoc network.
As a consequence, the seamless integration of mobile ad hoc networks with other wireless networks and fixed infrastructures will be an essential part of the evolution towards future fourth generation communication networks.
RAKESH K.R
[attachment=12945]
INTRODUCTION
A "mobile ad hoc network" (MANET) is an autonomous system of mobile routers connected by wireless links.
Rapidly deployable, self configuring.
No need for existing infrastructure.
Wireless links.
Nodes are mobile, topology can be very dynamic.
A MANET can be a standalone network or it can be connected to external networks(Internet).
History of MANETs
FIRST GENERATION:- The first generation goes back to 1972. At the time, they were called PRNET (Packet Radio Networks).
SECOND GENERATION:- The second generation of ad-hoc networks emerged in 1980s,when the ad-hoc network systems were further enhanced and implemented as a part of the SURAN (Survivable Adaptive Radio Networks) program.
THIRD GENERATION:-
Present ad-hoc networks systems are considered as the third generation.
WIRED VS WIRELESS NETWORKS
Wired Networks:- These networks are generally connected with the help of wires and cables.
Wireless Networks:- Wireless networks use some sort of radio frequencies in air to transmit and receive data instead of using some physical cables.
FEATURES OF MANET
Dynamic Topologies.
Bandwidth-constrained, variable capacity links.
Power-constrained operations.
Limited physical security.
ROUTING PROTOCOLS FOR MANET
TABLE DRIVEN PROTOCOL
Table driven protocols are close to wired routing protocols in the manner that the routing table is built before the data has to be sent.
The disadvantage of this principle is to not be reactive to topology changes, as the tables are pre- established.
DESTINATION SEQUENCED DISTANCE VECTOR(DSDV)
ALGORITHM
With DSDV , routing table will contain
The destination address
The number of hops required to reach the destination
The new sequence number, originally stamped by the destination
On-demand style: create routes only when it is desired by the source node
When a node requires a route to a destination,
it initiates a route discovery process
Route is maintained until destination becomes unreachable, or source no longer is interested
in destination.
Ad-Hoc On-Demand Distance Vector Routing (AODV)
Builds on DSDV algorithm and the improvement is on minimising the number of required broadcasts by creating routes on an on-demand basis (not maintaining a complete list of routes)
Broadcast is used for route request
Advantages: uses bandwidth efficiently, is responsive to changes in topology, is scalable and ensures loop free routing
Drawbacks: nodes use the routing caches to reply to route queries. Result: “uncontrolled” replies and repetitive updates in hosts’ caches yet early queries cannot stop the propagation of all query messages which are flooded all over the network
APPLICATIONS OF MANET
Tactical networks
Emergency services
Home and enterprise
Networking
Education
Entertainment
USES OF MOBILE AD HOC NETWORKS
Extending Coverage
Communicating Where No Infrastructure Exists
Community Networks
PROBLEMS IN MANET
Security
Bandwidth
Energy
Asymmetric Connections
Interference
Dynamic Topology
Routing Overhead
ADVANTAGES AND DISADVANTAGES
The following are the advantages of MANETs:
They provide access to information and services regardless of geographic position.
These networks can be set up at any place and time.
These networks work without any pre-existing infrastructure.
Some of the disadvantages of MANETs are:
Limited resources. Limited physical security.
Intrinsic mutual trust vulnerable to attacks. Lack of authorization facilities.
Volatile network topology makes it hard to detect malicious nodes.
CONCLUSION
The rapid evolution in the field of mobile computing is driving a new alternative way for mobile communication, in which mobile devices form a self-creating, self organising and self-administering wireless network,called a mobile ad hoc network.
As a consequence, the seamless integration of mobile ad hoc networks with other wireless networks and fixed infrastructures will be an essential part of the evolution towards future fourth generation communication networks.
