1

Glenn Research Center Satellite Networks & Architectures BranchCommunications Technology Division

Will IvancicNASA Glenn Research Center

Delay/Disruption Tolerant Networksin a Nutshell(DTN-101)

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Glenn Research Center Satellite Networks & Architectures BranchCommunications Technology Division

DTN in a Nutshell

DTN Source

DTN Bundle Forwarding Agent

DTN Destination

Where are you headed?

Knoxville, Wheeling,

then Fort Pitt.

Can you take this letter to my brother at

Fort Pitt?

Yes Mam, I sure can.

Dave Smith

@ Ft. Pitt

Dave Smith

@ Ft. Pitt

This is bundling

This is “opportunistic”bundle-agent

discovery (see slide 6)

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Glenn Research Center Satellite Networks & Architectures BranchCommunications Technology Division

DTN in a Nutshell

DTN Bundle Forwarding Agent

Dave Smith

@ Ft. Pitt

DTN Bundle Forwarding Agent

DTN Destination

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Glenn Research Center Satellite Networks & Architectures BranchCommunications Technology Division

Why DTN?

• Cons– May be considered a non-optimal solution for

particular situations such as if limited infrastructure exists• e.g. point-to-point links with no additional

network infrastructure such as relays– Adds Overhead

• Can be significant overhead depending on the bundle size

• May add significant unnecessary overhead for very simple network topologies/environments

• Pros– Flexibility– Reliability– Robustness

DTN is a network overlay abstraction. • This requires overhead.• Either one is willing to trade overhead for

flexibility, reliability and robustness, or one is not.

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Glenn Research Center Satellite Networks & Architectures BranchCommunications Technology Division

Delay/Disruption Tolerant Network (DTN)

• Goal: A standardized store and forward protocol and routing protocol

• Designed for extreme environments– Large transmission link delays – Extended periods of network partitioning– Routing capable of operating efficiently in the following

environments• Frequently disconnected• Pre scheduled• Opportunistic link availability• High per-link error rates making end-to-end reliability difficult• Heterogeneous underlying network technologies (including non-IP-based internets)

• The architecture operates as an overlay network– Institutes a new naming architecture based on Uniform Resource

Identifier (URI)

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Glenn Research Center Satellite Networks & Architectures BranchCommunications Technology Division

Opportunistic

(intermittent

connectivity,

short delay)

DTN Environments

Sched

uled

(long dela

y)

Opportunistic(intermittent connectivity, short delay)