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Mobile ad hoc networking: imperatives and challenges

Mobile ad hoc networking: imperatives and challenges. Imrich Chlamtac, Marco Conti, Jennifer J.N. Liu 2005. 10. 10. MMLAB, Seongil Han sihan@mmlab.snu.ac.kr. Contents. Introduction Mobile ad hoc network research Medium Access Control Networking issues Applications and middleware

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Mobile ad hoc networking: imperatives and challenges

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  1. Mobile ad hoc networking: imperatives and challenges Imrich Chlamtac, Marco Conti, Jennifer J.N. Liu 2005. 10. 10. MMLAB, Seongil Han sihan@mmlab.snu.ac.kr

  2. Contents • Introduction • Mobile ad hoc network research • Medium Access Control • Networking issues • Applications and middleware • Cross layers’ research issues • Discussion and conclusions

  3. Introduction • Mobile Ad hoc Network (MANET) • Sensor network • An important part of the 4G architecture • Non infrastructure based • Spontaneous networking • Can be connected to a backbone network • Attractive technology

  4. MANET issues • Traditional problems of wireless network • Channel characteristics • Hidden and exposed terminal • MANET specifics • Autonomous and infrastructure-less • Multi-hop routing • Dynamically changing network topology • Variation in link and node capabilities • Energy constrained operation • Network scalability

  5. Research area • 3 layers and cross layers issues

  6. Medium Access Control • Bluetooth • De-facto standard • For low-cost, short-range radio links • Contention-free token-based multi-access • Masters and slaves • Many applications is developed and being developed. • Mobile phone, headset, etc. • The scatternet • Multi-hop Bluetooth networks, interconnecting several piconets • Various formation algorithm

  7. Medium Access Control (cont.) • IEEE 802.11 • Infrastructure-based and infrastructure-less • Little or no attention was given to Ad hoc mode • With TCP, problems get large • HiperLAN • ETSI has promoted • “High Performance Radio Local Area Network” • HiperLAN/2 is noticeable

  8. MAC research issues • Random access • Used by most proposal • Collision avoidance and utilization maximization • Hidden-terminal and exposed-terminal problem • Controlled access • More suitable for QoS • Handling dynamic change of topology • TDMA • Time Spread Multiple Access (TSMA)

  9. Networking • Considerations • Self-organizing, dynamic, energy-constrained • Location service • Reactive and proactive • Routing and forwarding algorithms • Unicast, geocast, multicast, broadcast • Redesign of Transport layer mechanisms • Mainly TCP issues

  10. Routing • Unicast • Proactive routing protocols • Table-driven, periodic and event-driven updates • DSDV, CGSR, WRP, OLSR, TBRPF, FSR • Reactive routing protocols • On demand, route discovery • DSR, AODV, TORA, ABR, SSR, ZRP • Multicast • Tree based : AMRoute, MAODV, AMRIS • Mesh based : CAMP, ODMRP

  11. Routing (cont.) • Location aware routing • Greedy forwarding, directed flooding, hierarchical routing • Clustering • Clusterhead • Inter-cluster, intra-cluster communication • Cluster bottleneck problem

  12. TCP issues • Impact of mobility • Route failure • Packet loss and increased delay • Exacerbate unfairness • Nodes’ interaction at MAC • Impact of TCP congestion window size • Small congestion windows is good • New mechanisms • Explicit Link Failure Notification (ELFN) • Ad hoc TCP (ATCP) • Link RED

  13. Applications and middleware • Applications • Tactical, sensor, emergency service, commercial environment, home and enterprie networking, educational application, entertainment, location aware services • Middleware • Provide service abstraction • Efficiency is open issue • Service discovery and location • QoS-Aware resource discovery

  14. Cross layers’ research issues • Energy conservation • Local strategy : power saving mode • Global strategy : maximize the network lifetime • Security • Attacks and protections • Cooperation • Simulation and performance evaluation • Quality of Service

  15. Security • Attacks • Passive attacks • Eavesdropping • Active attacks • Impersonation, Denial of Service, Disclosure attack • Security mechanism • Preventive and detective • Key-based, Intrusion detection • Wired Equivalent Privacy • Secure routing • Wormhole attack

  16. Discussion and conclusions • The center of evolution • Toward 4G wireless technology • Flexibility, easy maintenance, infrastructure-less, auto-configuration, self-administration capability, cost advantage • IETF MANET WG • “killer application(s)” has yet emerged. • Many open research issues

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