Mobile ad hoc network (MANET), or simply ad hoc network, comprises nodes that freely and dynamically self-organize into arbitrary and temporary network topology without any infrastructure support.

1. TARUN VARSHNEY
varshney@live.in
Department of Information Technology
ABES Engineering College
MANET : The Art of Networking
without a Network

2. Wireless Networks
• Computer network that is wireless
• Infrastructure-based networks
• Less expensive to setup
IP backbone
Server
Router
Gateways

3. Disadvantages
• Disaster areas
• no infrastructure
• Large construction sites
• Too expensive
• Inconvenient
• Military operations

4. Solution???
• Mobile ad hoc network
• Mobile ad hoc network (MANET), or simply ad hoc network, comprises
nodes that freely and dynamically self-organize into arbitrary and temporary
network topology without any infrastructure support.

5. Mobile
Random and perhaps changing
Ad Hoc
Not engineered i.e. made or happening only for a particular purpose or
need, not planned before it happens
Network
Network, is a collection of systems and other hardware interconnected by
communication channels that allow sharing of resources and information
MANET: Mobile Ad hoc Network

6.  MANET is a self-configuring network of mobile nodes connected by
wireless links - the union of which form an arbitrary topology.
 Individual nodes act as routers
 Minimal configuration and quick deployment make ad hoc networks
suitable for emergency situations like natural or human-induced
disasters, military conflicts, emergency medical situations etc.
 Such a network may operate in a standalone fashion, or may be
connected to the larger Internet.
MANET: Mobile Ad hoc Network (continued)

7. Mobile Ad Hoc Network (MANET) is a collection of two or more
devices or nodes or terminals with wireless communication and
networking capability that communicate with each other without the
aid of any centralized administrator also the wireless nodes that can
dynamically form a network to exchange information without using any
existing fixed network infrastructure
MANET: Mobile Ad hoc Network (continued)

8. MANETs: Operation
A
B
C
D
E
F
Internet
E
Gateway
Stand-alone MANET
After one of the nodes is configured as a gateway, the entire network is
connected to an external network like Internet

9. Mobile Ad Network – HOME
A
B
C
MANET: Formation

10. MANET: Architecture

11. Collision – Hidden-Station Problem
• A wishes to communicate with B. However A cannot detect communication from C but
can detect communication from B.
• C also wishes to communicate with B. Again C cannot detect communication from A but
can detect Communication from B.
• C is hidden from A and A is hidden from C.
• Both A and C transmit and their signals collide leading to loss of both packets.

12. Collision – Exposed-station Problem
• Nodes A, B, and C can all detect communications from one another. However, Only C can
detect communication from D.
• Node B wishes to send to Node A and Node C wishes to send to Node D.
• So Node B begins transmitting to Node A and Node C recognizes this. The medium is in
use so Node C can not transmit to Node D.
• Even though both transmission requests could be made going in opposite directions, the
transmission does not happen. This is because Node C is exposed to Nodes A and B while D
is not.

13. Routing is the process of selecting paths in a network along which to send
network traffic
Routing Protocols are the set of rules and regulation that are must followed
during the communication over the network.
MANET: Routing and Routing Protocols

14. MANET: Classification of Routing Protocol
 Proactive Routing Protocol or Table Driven Approaches:
Maintain regular and up to date routing information about each node in the network by
propagating route updation at fixed time interval throughout the network.
 Reactive Routing Protocol:
Establish the route to a destination only when there is a demand for it.
Also called as “Demand Protocol”.
 Hybrid Routing Protocol:
Combination of proactive and reactive protocol
The route is established with the proactive routes and uses reactive flooding for new
mobile nodes.

15.  Reactive Routing Protocol
Ad Hoc On-Demand Distance Vector (AODV)
Dynamic Source Routing (DSR)
Associativity Based Routing (ABR)
 Proactive Routing Protocol
Destination-Sequenced Distance-Vector Routing (DSDV)
Optimized Link State Routing (OLSR)
The Wireless Routing Protocol (WRP)
MANET: Routing Protocols (continued)
 Hybrid Routing Protocol
Temporary Ordered routing Algorithm (TORA)
Zone Routing Protocol (ZPR)
Order One routing Protocol(OOPR)

16.  Constructs route on demand and reduce routing load.
 Uses table driven routing framework.
 Destination sequence number for routing packets to destination mobile nodes.
 Location independent algorithm.
 Bi-directional route.
 Packet send from source to destination, floods the network with the RREQ
packets. All mobile node receive RREQ from neighbor or update message then
checks routing table to find out that if it is the destination node or if it has fresh
route to the destination then unicast RREP which is routed back on a temporary
reverse route generated by RREQ from source node or else it re-broadcast RREQ.
Ad Hoc On-Demand Distance Vector (AODV)

17. The Internet Engineering task Force MANET working group suggests two
different types of matrices for Evaluting the performance of the protocols of the
MANETs
 Qualitative Metrics
 Quantitative Metrics
Performance and Evaluation issues of Routing Protocols

18. Qualitative Metrics
Qualitative metrics include the :
• Loop Freedom
• On-Demand Routing Behavior
• Proactive Behavior
• Security
• Unidirectional Link Support
• Sleep Mode

19. Quantitative Metrics
Quantitative metrics broadly includes the:
• End-to-end data throughput and delay
• Route Acquisition Time
• Out-of-Order Delivery
• Efficiency

20. Challenges in Securing MANETs
To secure an ad hoc network, the following attributes may be considered:
- Availability
- Confidentiality
- Integrity
- Authentication

21. Challenges in Securing MANETs
• Security exposures of ad hoc routing protocols are due to two different types of attacks:
- Active attacks through which the misbehaving node has to bear some energy costs in
order to perform some harmful operation, and
- Passive attacks that mainly consist of lack of cooperation with the purpose of energy
saving.
• Nodes that perform active attacks with the aim of damaging other nodes by causing
network outage are considered to be malicious.
• Nodes that perform passive attacks with the aim of saving battery life for their own
communications are considered to be selfish
• Selfish nodes can severely degrade network performances and eventually partition the
network

22. Challenges in Securing MANETs
• In a wormhole attack a malicious node can record packets (or bits) at one
location in the network and tunnel them to another location through a
private network shared with a colluding malicious node.
• Most existing ad hoc routing protocols would be unable to find consistent
routes to any destination
• When an attacker forwards only routing control messages and not data
packets, communication may be severely damaged

23. Challenges in Securing MANETs
- Wormhole Attacks
Initial
Routing
before attack

24. Challenges in Securing MANETs
- Wormhole Attacks
Initial
Routing
before attack

25. Challenges in Securing MANETs
- Wormhole Attacks
Tunnel packets received in one
place of the network and
replay them in another place
The attacker can have no key
material. All it requires is
two transceivers and one
high quality out-of-band
channel

26. Challenges in Securing MANETs
- Wormhole Attacks
Most packets will be
routed to the
wormhole
The wormhole can
drop packets or
more
subtly, selectively
forward packets
to avoid detection

27. MANET Applications
• Tactical Networks
• Military communication, operation
• Automated Battlefields
• Sensor Networks
• Home applications: allow users to manage home device locally and
remotely

28. MANET Applications (continued)
• Emergency Services
• Replacement of a fixed infrastructure in case of
earthquake, hurricanes
• Home and Enterprise Networking
• Shared whiteboard applications
• Use PDA to print anywhere
• Entertainment
• Multi-user games
• Robotic pets

29. • MANETs is challenging and promising system concepts
• Requires new type of architectures and protocols
• Open areas
• Secure routing protocol
• Quality of service
• Low power consumption
Conclusion

30. Conclusion
• Security of ad hoc networks has recently gained momentum in the
research community
• Due to the open nature of ad hoc networks and their inherent lack of
infrastructure, security exposures can be an impediment to basic
network operation
• Security solutions for MANET have to cope with a challenging
environment including scarce energy and computational resources and
lack of persistent structure

31. • The solutions presented in this presentation only cover a subset of all
threats and are far from providing a comprehensive answer to the security
problem in ad hoc networks
• They often address isolated issues away from a global approach to security
• As the technology for ad hoc wireless networks gains maturity,
comprehensive security solutions based on realistic trust models and
addressing all prevalent issues like routing, key management and
cooperation enforcement are expected to appear
Conclusion