1 mobile ad hoc networking: imperatives and challenges imrich chlamtac, marco conti, jennifer j.n....
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Mobile ad hoc networking: imperatives and challenges
Imrich Chlamtac, Marco Conti, Jennifer J.N. Liu
2005. 10. 10.MMLAB, Seongil Han
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Contents Introduction
Mobile ad hoc network research
Medium Access Control
Networking issues
Applications and middleware
Cross layers’ research issues
Discussion and conclusions
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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
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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
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Research area 3 layers and cross layers issues
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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
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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
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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)
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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
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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
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Routing (cont.) Location aware routing
Greedy forwarding, directed flooding, hierarchical routing
Clustering Clusterhead Inter-cluster, intra-cluster communication Cluster bottleneck problem
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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
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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
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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
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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
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Discussion and conclusions The center of evolution
Toward 4G wireless technology Flexibility, easy maintenance, infrastructure-less, a
uto-configuration, self-administration capability, cost advantage
IETF MANET WG “killer application(s)” has yet emerged. Many open research issues