22-04-2011, 04:11 PM
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The manet problem
Mobile
Random and perhaps constantly changing
Ad-hoc
Not engineered
Networks
Elastic data applications which use networks to communicate
WHAT IS MANNET ?
Mobile Adhoc Network (MANET) is a collection of independent mobile nodes that can communicate to each other via radio waves. The mobile nodes that are in radio range of each other can directly communicate, whereas others needs the aid of intermediate nodes to route their packets. These networks are fully distributed ,and can work at any place without the help of any infrastructure. This property makes these networks highly roboust.
Its characteristics
Nodes can perform the roles of both hosts and routers.
Nodes in mobile ad-hoc network are free to move and organize themselves in an arbitrary fashion
No centralized controller and infrastructure.
Intrinsic mutual trust.
Dynamic network topology.
Frequent routing updates.
WHY IT EMERged
Limitations of the Wireless Network
packet loss due to transmission errors
variable capacity links
frequent disconnections/partitions
limited communication bandwidth
Broadcast nature of the communications
Limitations Imposed by Mobility
dynamically changing topologies/routes
lack of mobility awareness by system/applications
Limitations of the Mobile Computer
short battery lifetime
limited capacities
Types of mannet
Vehicular Ad Hoc Networks (VANETs) are used for communication among vehicles and between vehicles and roadside equipment.
Intelligent vehicular ad hoc networks (InVANETs) are a kind of artificial intelligence that helps vehicles to behave in intelligent manners during vehicle-to-vehicle collisions, accidents, drunken driving etc.
Internet Based Mobile Ad hoc Networks (iMANET) are ad hoc networks that page link mobile nodes and fixed Internet-gateway nodes. In such type of networks normal ad hoc routing algorithms don't apply directly.
A Typical MANET
Examples of such networks
Sensor networks
Automotive networks
Military applications
Sensor networks
Networks deployed in random distribution
Low power
Delivering sensor data to a central site for some purpose
Traffic networks
“Smart cars” and “smart roads”
Onboard systems “talk” to the “road”:
Map obstacles and delays
Obtain maps
Inform the road of its actions
Military applications
Combat regiment in the field
Perhaps 4000-8000 objects in constant unpredictable motion…
Intercommunication of forces
Proximity, function, plan of battle
Special issues
Low probability of detection
Random association and topology
OTHER Applications
Personal area networking
cell phone, laptop, ear phone, wrist watch
Military environments
soldiers, tanks, planes
Civilian environments
taxi cab network
meeting rooms
sports stadiums
boats, small aircraft
Emergency operations
search-and-rescue
policing and fire fighting
Medium Access Control in MANET
Exposed Terminal Problem
Hidden Terminal Problem
Exposed terminal problem
In wireless networks, the exposed node problem occurs when a node is prevented from sending packets to other nodes due to a neighboring transmitter. Consider an example of 4 nodes labeled R1, S1, S2, and R2, where the two receivers are out of range of each other, yet the two transmitters in the middle are in range of each other. Here, if a transmission between S1 and R1 is taking place, node S2 is prevented from transmitting to R2 as it concludes after carrier sense that it will interfere with the transmission by its neighbor S1. However note that R2 could still receive the transmission of S2 without interference because it is out of range of S1.
The manet problem
Mobile
Random and perhaps constantly changing
Ad-hoc
Not engineered
Networks
Elastic data applications which use networks to communicate
WHAT IS MANNET ?
Mobile Adhoc Network (MANET) is a collection of independent mobile nodes that can communicate to each other via radio waves. The mobile nodes that are in radio range of each other can directly communicate, whereas others needs the aid of intermediate nodes to route their packets. These networks are fully distributed ,and can work at any place without the help of any infrastructure. This property makes these networks highly roboust.
Its characteristics
Nodes can perform the roles of both hosts and routers.
Nodes in mobile ad-hoc network are free to move and organize themselves in an arbitrary fashion
No centralized controller and infrastructure.
Intrinsic mutual trust.
Dynamic network topology.
Frequent routing updates.
WHY IT EMERged
Limitations of the Wireless Network
packet loss due to transmission errors
variable capacity links
frequent disconnections/partitions
limited communication bandwidth
Broadcast nature of the communications
Limitations Imposed by Mobility
dynamically changing topologies/routes
lack of mobility awareness by system/applications
Limitations of the Mobile Computer
short battery lifetime
limited capacities
Types of mannet
Vehicular Ad Hoc Networks (VANETs) are used for communication among vehicles and between vehicles and roadside equipment.
Intelligent vehicular ad hoc networks (InVANETs) are a kind of artificial intelligence that helps vehicles to behave in intelligent manners during vehicle-to-vehicle collisions, accidents, drunken driving etc.
Internet Based Mobile Ad hoc Networks (iMANET) are ad hoc networks that page link mobile nodes and fixed Internet-gateway nodes. In such type of networks normal ad hoc routing algorithms don't apply directly.
A Typical MANET
Examples of such networks
Sensor networks
Automotive networks
Military applications
Sensor networks
Networks deployed in random distribution
Low power
Delivering sensor data to a central site for some purpose
Traffic networks
“Smart cars” and “smart roads”
Onboard systems “talk” to the “road”:
Map obstacles and delays
Obtain maps
Inform the road of its actions
Military applications
Combat regiment in the field
Perhaps 4000-8000 objects in constant unpredictable motion…
Intercommunication of forces
Proximity, function, plan of battle
Special issues
Low probability of detection
Random association and topology
OTHER Applications
Personal area networking
cell phone, laptop, ear phone, wrist watch
Military environments
soldiers, tanks, planes
Civilian environments
taxi cab network
meeting rooms
sports stadiums
boats, small aircraft
Emergency operations
search-and-rescue
policing and fire fighting
Medium Access Control in MANET
Exposed Terminal Problem
Hidden Terminal Problem
Exposed terminal problem
In wireless networks, the exposed node problem occurs when a node is prevented from sending packets to other nodes due to a neighboring transmitter. Consider an example of 4 nodes labeled R1, S1, S2, and R2, where the two receivers are out of range of each other, yet the two transmitters in the middle are in range of each other. Here, if a transmission between S1 and R1 is taking place, node S2 is prevented from transmitting to R2 as it concludes after carrier sense that it will interfere with the transmission by its neighbor S1. However note that R2 could still receive the transmission of S2 without interference because it is out of range of S1.
