1. Mobile ad hoc networking: imperatives and challenges

2. Agendas Wireless networks Ad hoc networks
Mobile ad hoc networks (MANET)
MANET applications
Enabling technologies
Security issues
Conclusions
Questions

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

4. Disadvantages Disaster areas Large construction sites
no infrastructure
Large construction sites
Too expensive
Inconvenient
Military operations
Less time to setup

5. 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. (Chlamtac, Conti, and Liu, 2003)

6. MANET Formed by wireless hosts
Without using pre-installed infrastructure
Routes between hops may contain multiple hops
Does not use centralized administration
MANETs are often referred to as multihop wireless and hoc networks

7. Key Elements of MANETs Formed dynamically through independent nodes
Nodes do not have any pre-specified nodes
Make decision based on the current network situation
Nodes are expected to behave as routers
As routers, nodes must assist in discovery and maintenance of network routes

8. MANET applications Tactical Networks Sensor Networks
Military communication, operation
Automated Battlefields
Sensor Networks
Home applications: allow users to manage home device locally and remotely
Environment applications: tracking the movements of animals

9. 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

10. Mobility Space divided into cells
A base station is responsible to communicate with hosts in its cell
Mobile hosts can change cells while communicating
Hand-off occurs when a mobile host starts communicating via a new base station

11. MANET Architecture

12. MANET Research activities
Based on its architecture, research activities are grouped into three main areas
Enabling technologies
Networking
Middleware and application

13. Enabling Technologies
Classification depends on networks coverage area
Body (BAN)
Personal (PAN)
Local (LAN)
Metropolitan (MAN)
Wide (WAN)

14. 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.

15. 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.

16. Research issues Energy conservation Network security and cooperation
Simulation and performance evaluation
Quality of service

17. Energy conservation Energy conservation Solution
Battery power is finite
Limits services and applications that the network can support
Solution
Topology management – goal is to reduce overall network power consumption
Routing protocols – minimize routing paths

18. Energy conservation (Continued)

19. Network Security - MANET
Physically insecure network
Network security requirements
Confidentiality
Authentication
Integrity
Non-repudiation
Availability

20. Eavesdropping Who has a radio receiverB C
Who has a radio receiver
Same frequency used by the ad hoc network
Man-in-the-middle attack

21. Impersonation - Security Attacks
Nodes join to the network undetectably
Black hole attack
Malicious node uses the same routing protocol
Advertise itself as having the shortest path
Worm hole attack
Create a tunnel(wormhole link) between two malicious nodes
Captures wireless transmission from one end
Sends them to the other end through that tunnel

22. Denial of Service - Security Attacks
Attempts to create routes to non-existent node
The attacker attempts to consume batteries of other nodes by requesting routes
Forwards unnecessary packets
Causes a system to be unavailability
A violation of security policy

23. Disclosure Attack - Security Attacks
Reveal the physical location of nodes
Reveal the structure of the network
Two security mechanisms are applied
Preventive
Detective
Mechanisms are based on key-based cryptography
Secret keys are distributed through a secure channel
Public keys are distributed through certificates

24. Quality of Service - MANET
Capability of network to provide better service
Controls jitter and latency
Manages and minimizes network congestion
Sharps network traffic
Sets network traffic priorities

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

26. Questions

27. References www.ietf.org/html.charters/manet-charter.html
I Chlamtac, M Conti, JJN Liu, "Mobile ad hoc networking: imperatives and challenges." Ad Hoc Networks, 1(1), pp , 2003.