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Mobile ad hoc networking: imperatives and challenges
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Agendas Wireless networks Ad hoc networks
Mobile ad hoc networks (MANET) MANET applications Enabling technologies Security issues Conclusions Questions
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Wireless networks Computer network that is wireless
IP backbone Server Router Gateways Computer network that is wireless Infrastructure-based networks Less expensive to setup
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Disadvantages Disaster areas Large construction sites
no infrastructure Large construction sites Too expensive Inconvenient Military operations Less time to setup
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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)
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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
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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
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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
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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
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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
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MANET Architecture
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MANET Research activities
Based on its architecture, research activities are grouped into three main areas Enabling technologies Networking Middleware and application
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Enabling Technologies
Classification depends on networks coverage area Body (BAN) Personal (PAN) Local (LAN) Metropolitan (MAN) Wide (WAN)
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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.
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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.
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Research issues Energy conservation Network security and cooperation
Simulation and performance evaluation Quality of service
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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
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Energy conservation (Continued)
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Network Security - MANET
Physically insecure network Network security requirements Confidentiality Authentication Integrity Non-repudiation Availability
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Eavesdropping Who has a radio receiver
B C Who has a radio receiver Same frequency used by the ad hoc network Man-in-the-middle attack
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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
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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
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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
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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
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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
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Questions
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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.
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