Opportunistic NetworkingNoorin Fatima

A little about a basic network…

• A Network has nodes that are interconnected to each other

• These nodes are usually static

• Communication path usually pre-determined (as in the Network Layer of the OSI Model)

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But in an OppNet…However, in an Opportunistic Network,• Nodes are mobile/fixed• Communication possible even if no

connecting route exists between nodes.

• Routes are built dynamically- i.e., communication path not predetermined

• For the next hop, a node would be opportunistically chosen only if it would bring the message closer to final destination

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How OppNets Work…• Each node receiving a message exploits

LOCAL knowledge to decide which is the best next hop, among its current neighbors, for the message to reach the eventual packet destination.

• When no forwarding opportunity exists(e.g., no other nodes are in the transmission range, etc), the node stores the message and waits for future contact opportunities with other devices to forward the information- an e.g. of Delay-Tolerant n/w.

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When nodes become sick!OppNets follow several kinds of

routing/forwarding techniques.

One interesting e.g, is: Epidemic Routing

Epidemic Routing-

• Messages diffuse in the n/w similar to disease or viruses by means of contact between nodes.

• A node is infected by a message when it either generates a message or, alternatively, receives it from another node for forwarding. (The infected node stores the msg in a local buffer)

• A node is susceptible to infection when it has not yet received the message.

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How OppNets work in real life…

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Two interesting projects deploying OppNets

1) ZebraNet

• A Princeton University project deployed in the vast savanna area of central Kenya

• Tracks wild species to investigate their behavior and understand their interactions among each other.

• Cost-effective and non-intrusive means to monitor large populations roaming in vast areas.

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Another Project is…2) DakNet:• It is aimed at providing cost-

effective connectivity to rural villages in India, where deploying a standard Internet access is not cheap.

• Kiosks are built up in villages and are equipped with digital storage and short-range wireless communications.

• Mobile Access Points (MAPs) mounted on buses, motorcycles, etc., exchange data with the kiosks wirelessly.

• MAPs may also download requested info (news, music, etc.) and bring it to villages.

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References

• Images from Google.com• Lucia Pelusi, A. Passarella, Marco Conti,

“Opportunistic Networking: Data Forwarding in Disconnected Mobile Ad Hoc Networks”, IEEE Communications Magazine, Nov, 2006, pp. 134-141.

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No Questions?!

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