DTN Network ManagementScenarios and General Requirements

Will Ivancicwilliam.d.ivancic@nasa.gov

216-433-3494

DTND is for Delay (Deep Space)

D is for Disruption (Military)D is for Disconnected (All)

3

DTN in a nutshellDTN 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

4

DTN in a nutshellDTN Bundle

Forwarding Agent

Dave Smith@ Ft. Pitt

DTN Bundle Forwarding Agent

DTN Destination

5

Why DTN? Cons

Non-Optimal Solution for particular situations such as if limited infrastructure exists

Adds Overhead Can be significant

overhead depending on the packet size

Pros Flexibility Reliability Robustness

DTN is a network overlay abstraction. • This requires overhead.• One is either willing to trade overhead for flexibility or they are not.

6

Delay/Disruption Tolerant Network (DTN)

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)

Concept of Late Binding of Name to Address

7

DTN Environments

Sched

uled

(long dela

y)

Opportunistic(Intermittent Connectivity, Short Delay)

8

Known problems with DTN bundling IRTF DTN Research Group adopted bundling as ‘universal’ way to

deal with DTNs. Currently not investigating alternatives. Bundling is not mature by any stretch of the imagination

Security, routing, naming, reactive fragmentation, key and policy management, etc. are still open issues.

Network overlays inherit all the good and bad of the underlying networks. Example, if one does not have a good handle of how to secure an ad hoc

network, running DTN over an ad hoc network implies one has to address both the ad hoc and the DTN issues (routing, quality of service, security, etc...)

The current bundle design has no built-in reliability checks. Security protocols are emphasized. Reliability is currently (as of November 2008) being retrofitted as an add-on to security. [Fixable]

The current bundling protocol (RFC 5050) assumes all nodes know current UTC thus requiring network synchronization. [Fixable]

Bundling is really still a research effort!

9

Palm Island Resort, Dubai, 14 Dec 2003 (UK-DMC)

www.dmcii.com

The Cape of Good Hope and False Bay. False colours – red is vegetation. Taken by UK-DMC satellite on the morning of Wednesday, 27 August 2008. Downloaded using bundling over Saratoga, with proactive fragmentation. Fragments assembled at NASA Glenn, then post processed at SSTL.First sensor imagery delivered by bundles from space.

10

Home Agent

VMOC

Open Internet

VMOCDatabase

SatelliteScheduler

& Controller

Ground Station 3

Ground Station 2Ground

Station 1

->> Time ->>

Large File TransferOver Multiple Ground Stations- DTN is a Potential Solution -

DTN Bundle AgentIntermediary

DTN Bundle AgentIntermediary

DTN Bundle AgentIntermediary

DTN Bundle AgentSink

Scenarios Deep Space Mars Relay Simple Sensor Networks Data Mule Rapid Disruption (Fades due to RF) Low Earth Orbiting Sensor Satellite Geostationary Bent Pipe Relay Satellite Unmanned Aeronautical Vehicles

Mars Relay Mars Odyssey Spacecraft +-------+ _ +-------+ | |:_:| | Deep Space Link +-------+ +-------+ _,,..--''' . . ___..---'' `. Proximity -.._ `. `. Link `- /\''' `. _,,. /__\ `,-' Deep ,'.------. Space `. / | Mars | Network `. | | Expl.| | | Rover| | `------'

Odyssey Relay Operations

Long DelayShort Delay

DTN Bundle Agent

DTN Bundle Agent

DTN Bundle Agent

UAV via GEO Satellite

DTNBundle Agent

DTNBundle Agent

DTNBundle Agent

RF RelayDTN

Bundle Agent

.-------. |Bundle | .-------. |Agent 1| |Bundle | .--o `-------' /''\. |Agent 5| / `. `. .' '._ .-----.,--. `-------' / | \ | `.._|Data | ``. \ / `. / |Mule | `-. \ ' |_ | `-----' `. ,/ | | Movement \.,.--- | ' <<======= | / | / | | Path Well .-------. | | Traveled |Bundle | | | |Agent 3| | / ...._ `-------' \ | | `. / `\ \ _.. | `./ .' `' `---`... `.._ `-. ,' .-------. _, ". ``. \ _,,' |Bundle |,' `. \ `--...,-'. |Agent 2| `. `. | `-------' `. _ \ .-------. ' `'-...._ | |Bundle | `"--------' |Agent 4|

Data Mule

LEO Sensor Satellite +-------+ _ +-------+ | |:_:| | +-------+ +-------+ ,' `. Space/Ground ,' `-. Space/Ground Link 1 ,-' `. Link 2 ,' `._ ,' `. ,' Connect Connect `._ _,' T1 T2 `. . ' ` / Ground `. ..,' Ground Station /\'' ___...------'''''''------....__ /\ Station 1 /__\.,--' `'--./__\ 2 _,,-' ._ _, `--.._ ' `. Ground/Ground Ground/Ground ,' ' `-. Link 1 Link 2 ,-' `._ ,-' `. _,' ' .-----------. | Data | |Collection | | Center | `-----------'

Low Earth Orbiting Satellite

Network Management  Monitoring and Measurement

Debugging and Troubleshooting Performance profiles -- delay and throughput; disruption

and connectivity  Configuration

Routing Security configurations (and policy) DTN-Tables ? (long term)

Applications (related to traffic generation for testing and monitoring purposes) General User Applications that can be use to test, stress

and exercise the network (i.e. DTNtraceroute, DTNsend/receive, DTNperf, etc...)

DTN useful applications (i.e DTNdatabase synchronization (DTNrsync), DTNmail, DTNchat ?, etc...)

Network ManagementMonitoring and Configuration General Requirements

Local Network Management Remote Network Management

Monitoring Bundle Processing System Characteristics

Convergence Layers Multi-Homing Radios Processing Power Onboard Storage

Configuration Routing Name Resolution Local and Network Time Security

Definitions Local Management ≡ Logged into the device

locally or via Real-time access such as via a connected IP network Assume high bandwidth, no disruption and

insignificant delay Remote Management ≡ Managed over a

DTN network Handles Long Delays, Long Periods of Disruption,

and Low Bandwidths

General Requirements Management and Configuration should work for all DTN

environments High delay, long periods of disconnection, low bandwidth System may be multiple hops away and never reachable in a

single hop System may not be synchronized

(although current bundling RFC 5050 assumes synchronization) Multiple security levels

Secure Login and encrypted data transfer (i.e. SSH or TLS for local management, something yet to be defined for remote management)

Monitoring - Modest Security Configuration - High Security

Remote Management uses bundling Remote Configuration

Incremental Test, Validation, restore/recovery

Utilities – beginnings of NetMgt(Make utilities interoperable between ION and DTN-2) DTN-ping DTN-send/receive DTN-traceroute DTN-perf DTN-heartbeat DTN-email DTN-chat Bundle Count / Traffic Measurement (NEW Request)

NASA DEN Phase-0 Scenario

Phase-0Continuous ConnectivityStatic routingNo BP Security

Delay: Lunar 3 secBW: 128kbps [>100Mbps]BP/LTP/Encap orBP/LTP/IP/Encap

Delay: 100s msec?BW: 72/k/192k

StoryEVA sending some sort of telemetry (different kinds to APL and JPL)Understand that EVA data wouldn’t really go to APL/JPL

BP/LTP/Encap or BP/LTP/IP/Encap?OhioU has TCPCL for ION?

BW: 10Mbps

Limit the amount of available storage (later)

DTNBone We invite you to participate in the DTNbone

Web Page http://www.dtnrg.org/wiki/DtnBone Mail list http://korgano.eecs.ohiou.edu/mailman/listinfo/dtnbone

Establish a worldwide collection of nodes running DTN bundle agents and applications. Remote management and control of nodes, Interoperability, Application deployment and testing, Operations across administrative boundaries.

DTNGW

Rover

Habitat

ScienceSensor

1 Mbps

256 kbps

128 kbpsEARTH

MOON

L2Relay

LunarRelay

Always ON ?

Intermittent

Multiple Switched Ground Stations emulated as one single DTN GW

InternationalPartner #2

InternationalPartner #1

Switched

DTNGW

L2Relay

Habitat

LunarRelay

Rover

Sensor

SW

SW

CS

CS

CS

CS

Real-time Control PlanDefined as part of Local Management

CS Channel Simulator(Rate, BER and Connectivity)

DTN Data Flow