Joint DTN / SOIS Meeting

© 2009 The MITRE Corporation. All rights reserved.

Joint DTN / SOIS Meeting

April 22, 2009Colorado Springs, CO


Page 2

Agenda

■ Current state of DTN– DTN Picture– RFCs– Implementations

■ DTN2■ ION

– NASA DTN-for-2010 program

■ Current State of SOIS


DTN as an Overlay Network

Page 4

Application

DTN

TCP

IPv6

Ethernet

UTP

DTN

TCP

IPv6

ATM

DS-1

IPv6

Ethernet

UTP

Onboard NetworkTerrestrial Wired Network

LTP

Encap

TC/TM

Application

DTN

Spacewire

DTNGateway

Long-HaulSpace Link

DTN

LTP

Encap

TC/TM Spacewire

DTNGatewayApplication

DTN

Transport

Network

Link

Physical

IP Router

ATM

DS-1

■ Convergence Layers: the “glue” that interfaces DTN to lower-layer protocols such as TCP, UDP, Ethernet, BlueTooth– Convergence layers just move data from DTN node to DTN node– Routing happens at the DTN layer (choosing the next DTN layer router)


■ Requests for Comments– Architecture (RFC4838)– Protocol Specification (RFC5050)

■ Review of the above by JAXA■ DTN Implementations

– DTN2 Reference Implementation– Interplanetary Overlay Network (ION) Implementation

■ DTN interfaces to the rest of the system– Applications (API)– Lower layers

■ DTN has a notion of ‘Convergence Layers’ for transporting DTN bundles across underlying technologies (TCP, UDP, LTP)

– Storage■ DTN really wants to commit data that cannot be forwarded to

persistent storage

DTN Info

Page 5


DTN Protocols


Bundles Built up out of Blocks

Page 7

Primary Bundle Block

Payload Block

Other Block (s)

Address information (source, dest, …),treatment flags, QoS marking, creation time, lifetime

Other capabilities, e.g. security, extended QoS markings, metadata describing the payload, at-most-one-of-this-kind

The application-layer payload


Primary Bundle Block

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Primary BundleBlock

Version (1 byte) Bundle Processing Control Flags (SDNV)

Block length (SDNV)

Destination Scheme Offset (SDNV)

Destination SSP Offset (SDNV)

Source Scheme Offset (SDNV)

Source SSP Offset (SDNV)

Report-To Scheme Offset (SDNV)

Report-To SSP Offset (SDNV)

Custodian Scheme Offset (SDNV)

Custodian SSP Offset (SDNV)

Creation Timestamp (SDNV) Creation Timestamp Sequence Number (SDNV)

Lifetime (SDNV) Dictionary Length (SDNV)

Dictionary (Byte Array)

Fragment Offset (SDNV, if fragment) Application data unit length (SDNV, if fragment)


2 1 0 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|Status Report| RESERVED|COS| General |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

0 -- Bundle is a fragment.1 -- Application data unit is an administrative record.2 -- Bundle must not be fragmented.3 -- Custody transfer is requested.4 -- Destination endpoint is a singleton.5 -- Acknowledgement by application is requested.6 -- Reserved for future use.The bits in positions 8 and 7 constitute a two-bit priority field :

00 = bulk01 = normal10 = expedited11 is reserved for future use.

9 -13 -- reserved for future use.14 -- Request reporting of bundle reception.15 -- Request reporting of custody acceptance.16 -- Request reporting of bundle forwarding.17 -- Request reporting of bundle delivery.18 -- Request reporting of bundle deletion.

Bundle Status Control Flags

Page 9

• Can be used to track the progress of a bundle in the network

• Signals can be generated but not forwarded (if no route exists) – pull accounting information only if there’s a network error


Primary Bundle Block: Address Information

Page 10

Primary BundleBlock


Block length (SDNV)













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Primary Bundle Block: Creation Time and Time To Live

Page 11

Primary BundleBlock


Block length (SDNV)













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■ The combination of (sending EID, Creation Timestamp, and Creation Timestamp Sequence Number) uniquely identifies a bundle

■ Loose time synchronization among nodes is required to support the time-to-live notion– Loose, like, to within 10s of seconds, e.g.

■ Some notion of using a countdown time instead of (creation, lifetime)

About Time

Page 12


+-----------+-----------+-----------+-----------+ |Block type | Block processing ctrl flags (SDNV)|+-----------+-----------+-----------+-----------+| Block length (SDNV) |+-----------+-----------+-----------+-----------+/ Block body data (variable) /+-----------+-----------+-----------+-----------+

06 5 4 3 2 1 0+-+-+-+-+-+-+-+| Flags |+-+-+-+-+-+-+-+Block Processing Control Flags Bit Layout0 - Block must be replicated in every fragment.1 - Transmit status report if block can't be processed.2 - Delete bundle if block can't be processed.3 - Last block.4 - Discard block if it can't be processed.5 - Block was forwarded without being processed.6 - Block contains an EID-reference field.

Extension Blocks

Page 13


NASA DTN-for-2010 Program

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Deep Impact Network Experiment (DINET)

Page 15


DTN Experimentation Network

GRCEVAION

JSCRoverION

GSFCW. Sands

ION

GSFCL. Relay

ION

JSCAltairION

MSFCMCC / POCC

DTN2/[TCP|UDP]JPLData ConsumerDTN2/[TCP/UDP]

APLData Consumer

ION

250ms: 128kbps [>100M

bps]

100ms : 72/k/192k

BP / UDP

20ms: 10Mbps

BP / UDP

BPLTPUDP

BPLTPUDP

JPLAthleteDTN2

BP / UDP

BP / TCP 0:0 0:0

0:020ms :

10Mbps

BPLTPUDP

BPUDP

EIDs: dtn://eva/*

EIDs: dtn://athlete/*

EIDs: dtn://rover/* EIDs: dtn://altair/* EIDs: dtn://relay/*

EIDs: dtn://whitesands/*EIDs: dtn://msfc/*

EIDs: dtn://aplsci/*

EIDs: dtn://jplsci/*


■ Network Management■ Time Synchronization■ Routing

Protocol Mechanisms

Page 17


DTN Research Group

Page 18


Naming Semantics

Page 19

Documents

Joint DTN / SOIS Meeting