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Wired Networks
◦ Infrastructure based
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Wireless networks
◦ infrastructure-based
 Rely on access point
 Nodes communicate through infrastructure (cannot communicate
directly with each other )
◦ infrastructure-less based
 does not rely on fixed infrastructure
 Nodes can communicate with each
other directly
 called an ad hoc wireless network.
 The word ad hoc can be translated
as “improvised” or “not organized
 An ad hoc mode is used to connect
wireless clients directly
together, without the need for a
wireless access point or a connection
to an existing wired network.
 they communicate with each other by
relying on peer-to-peer routing.
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Formed by wireless hosts which may be mobile
No pre-existing infrastructure
Routes between nodes may potentially contain multiple hops
◦ Nodes act as routers to forward packets for each other
◦ Node mobility may cause the routes to change
B
A
A
B
C
C
D
D
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Advantages: low-cost, flexibility
◦ Ease & Speed of deployment
◦ Decreased dependence on infrastructure

Applications
◦ Military environments
 soldiers, tanks, planes
◦ Civilian environments
 vehicle networks
 conferences / stadiums
 outside activities
◦ Emergency operations
 search-and-rescue / policing and fire fighting

Collaboration
◦ Collaborations are necessary to maintain a MANET
and its functionality.
◦ How to collaborate effectively and efficiently?
◦ How to motivate/enforce nodes to collaborate?

Dynamic topology
◦ Nodes mobility
◦ Interference in wireless communications
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has a feature of distributed operation
have lower bandwidth capacity as compared with wired
networks.
◦ MANETs can experience a problem of higher bit error rate and
lower bandwidth capacity

limited energy resource , battery operated
◦ it has to be used very efficiently.

Security
◦ the nodes and the information in MANETs are not secured from
threats,
◦ mobile devices imply higher security risks compared with fixed
operating devices, because portable

Mobility
◦ dynamic topology
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According to communication
◦ Single hop
◦ Multi hop
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According to topology
◦ Flat
◦ Hierarchical (clusters: master node and normal nodes)
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According to node configuration
◦ Homogeneous
◦ Heterogeneous
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According to coverage area
◦ BAN, PAN, LAN, MAN, WAN