Delay Tolerant Networking Birds of a Feather , 4 October 2007 Heppenheim, Germany

4 October, 2007CCSDS DTN BoF -- Heppenheim2 Original Agenda TimeTopicPresenter Possible space mission drivers for DTN technology: MERs ESA Others? Current state of the IRTF DTN Protocol. How good a fit is it for CCSDS? Documents (Arch, Protocol Spec) DTN2 ION Protocol overhead Documents Security Keith Scott, Scott Burleigh Solicitation of interest: do we think CCSDS should invest in standardizing DTN technology and protocol(s)? Poll for agency support Assuming interest, how to incorporate DTN into CCSDS (adopt, adapt [issues?], …)? Discussion Draft DTN WG Charter Discussions Agency support (resources) Schedule (1 year?) How to specify? 2 implementation req’t?s Discussion

4 October, 2007CCSDS DTN BoF -- Heppenheim3 Proposed Agenda Partial Order Topic FirstDTN Overview –DTN as a formalization of long-term store-and-forward relay technologies –Overlay network on top of [transport | network | link] –DTN as a refactorization and generalization of CFDP with additional capabilities –Relationship to Mars Interoperability WG SecondCurrent state of DTN Protocol and Implementations –Specifications (Architecture, Protocol, Security) –DTN2 Reference Implementation –Interplanetary Overlay Network (ION) Architectures and interoperability points DTN activities LastDTN WG Charter Discussions (assumes interest in WG formation) –Agency support (resources) –How to incorporate DTN into CCSDS (adopt, adapt [issues?], …)? –Schedule?

4 October, 2007CCSDS DTN BoF -- Heppenheim4 Why IP Doesn’t Make Sense In Disconnected Environments End-to-end (IP): Must wait for complete path DTN: Incremental progress w/o end-to-end path source destination source destination S D S D S D TCP/UDP Throughput DTN Latency TCP/UDP Latency Link 1 Link 2 Link 3 Link 4 Link 1 Link 2 Link 3 Link 4 DTN Throughput Time

4 October, 2007CCSDS DTN BoF -- Heppenheim5 DTN in a Nutshell “Postal model” of Communications Store and Forward, minimal interactivity source destination Persistent Storage Routing Disrupted Region DTN provides network services across disruption and massive differences in delay and bandwidth Link Decoupling

4 October, 2007CCSDS DTN BoF -- Heppenheim6 DTN Overlay Network DTN interconnects disparate networking regions –Operates above regional transport layer stacks –Allows flexibility to adapt to specific environments Application DTN Transport Network Link Phy DTN Transport Network Link Phy Network Link Phy Terrestrial NetworkPlanetary-local Network Transport Network Link Phy Application DTN Transport Network Link Phy DTN Gateway Deep Space DTN Transport Network Link Phy Transport Network Link Phy DTN Gateway persistent storage

4 October, 2007CCSDS DTN BoF -- Heppenheim7 DTN Overlay Network for Deep Space (No Relays Yet) For space, DTN can run over CCSDS protocols –Could also run directly over space packets, e.g. CFDP / AMS DTN Transport Network Link Phy DTN Transport Network Link Phy Network Link Phy Terrestrial NetworkPlanetary-local Network LTP Pkts AOS CFDP / AMS DTN TCP IP Link Phy DTN Gateway Deep Space DTN LTP Pkts AOS TCP IP Link Phy DTN Gateway persistent storage

4 October, 2007CCSDS DTN BoF -- Heppenheim8 LTP Pkts AOS LTP Pkts AOS DTN Accounting: Custody Transfer DTN reliability is via custody transfer –Once custody has been accepted by a downstream bundle, the current custodian is safe to remove it CFDP / AMS DTN Transport Network Link Phy DTN Transport Network Link Phy Network Link Phy Terrestrial NetworkPlanetary-local Network CFDP / AMS DTN TCP IP Link Phy DTN Gateway Deep Space DTN TCP IP Link Phy DTN Gateway persistent storage Custody Transfers

4 October, 2007CCSDS DTN BoF -- Heppenheim9 LTP Pkts AOS LTP Pkts AOS DTN Accounting: Status Reports DTN provides a number of status reports for accountability from intermediate nodes –Time of (receipt, custody, forwarding, deletion) –Settable on a per-bundle basis CFDP / AMS DTN Transport Network Link Phy DTN Transport Network Link Phy Network Link Phy Terrestrial NetworkPlanetary-local Network CFDP / AMS DTN TCP IP Link Phy DTN Gateway Deep Space DTN TCP IP Link Phy DTN Gateway persistent storage Bundle status reports from intermediate nodes

4 October, 2007CCSDS DTN BoF -- Heppenheim10 LTP Pkts AOS LTP Pkts AOS DTN Accounting: Delivery Report One of the status reports is a delivery receipt, indicating the the bundle has been delivered to the destination application CFDP / AMS DTN Transport Network Link Phy DTN Transport Network Link Phy Network Link Phy Terrestrial NetworkPlanetary-local Network CFDP / AMS DTN TCP IP Link Phy DTN Gateway Deep Space DTN TCP IP Link Phy DTN Gateway persistent storage End-to-End Delivery Receipt

4 October, 2007CCSDS DTN BoF -- Heppenheim11 DTN’s Derived Design Rules Don’t plow the same ground twice – hold the gains you’ve achieved Don’t engage in unnecessary chit-chat – build complete transactions and make network accesses count Don’t depend on information from inaccessible / remote places if you can avoid it – build a sequence of local control operations and use late binding Don’t force homogeneity – allow different network components to use environmentally-relevant optimizations

4 October, 2007CCSDS DTN BoF -- Heppenheim12 Circa 2002 Demonstration

4 October, 2007CCSDS DTN BoF -- Heppenheim13 Relationship to Mars Interoperability Working Group Mars Interop. WG standardizes the parameters and options for the various data links, concentrating on the relay orbiter-to-remote surface interface –Reliability, accounting, file transfer left to upper layers –DTN can provide these

4 October, 2007CCSDS DTN BoF -- Heppenheim14 Space Relay Requirements Support for automated multi-hop data relay between remote elements and Earth –Short local control loops enable finer-grained decision making and better performance –Cross-support between different agencies’ assets CCSDS-wide naming / addressing scheme to allow unified and unambiguous identification of communications endpoints –Supports cross-support between different agencies’ assets –Something for SANA to manage

4 October, 2007CCSDS DTN BoF -- Heppenheim15 Why DTN? Capabilities: –Reliable delivery via custody transfer –Built-in accounting mechanisms (time of receipt, time of forward, …) –Precedence –Extensibility –Security that protects the infrastructure DTN Provides more than CFDP alone –Additional per-hop accounting plus end-to-end delivery notifications –DTN supports fragmentation and delivery over multiple parallel paths –Security Cleanly extend terrestrial endpoint past end of space data link (cross-support of IP on the ground would make this cross- supportable) Generalization (refactoring) of CFDP capabilities to provide both message and file paradigms

Current Status of DTN

4 October, 2007CCSDS DTN BoF -- Heppenheim17 Current State of DTN Delay Tolerant Networking is being developed under the Internet Research Task Force –Architecture document: RFC4838 –Bundle Protocol Specification: In process to be published as an informational RFC Optional reliability via custody transfer End-to-end and hop-by-hop security mechanisms –Security Draft-irtf-dtnrg-sec-overview-03 Draft-irtf-dtnrg-bundle-security-04 –Bundle Authentication –Payload Security –Payload Encryption Implementations –DTN2 reference implementation (available from dtnrg.org) –JPL Interplanetary Overlay Network (ION) implementation –TKK implementation for Symbian cellphone –Georgia Tech.Net implementation

4 October, 2007CCSDS DTN BoF -- Heppenheim18 Interoperability at IETF67 TKKDTN2MITRE*BBN*GA TechION Language C++ C++, JavaC#C Platform Symbian cellphone MacOs and Linux on PC and Nokia 770 Linux on PC; external router Linux on PC; external CL adapter.NET on Win32 & Linux on PC & PDA Linux on PC Custody Transfer Status Reports TCP CL UDP CL * Derived from DTN2 RI November 5-10, 2006

4 October, 2007CCSDS DTN BoF -- Heppenheim19 Topology for IETF67 Interoperability Tests Demmer-mac.11, RI BBN, java.31, RI ext CL Demmer-pc.12 Pocket, C#.63 jpl1.23, ION mitre2.52, RI War, C# , RI on Nokia770 mitre.51, RI ext Rtr 9300, C++.41, Symbian tcp udp tcp Status reports direct to demmer-mac Destination dtn://9300.dtn/send udp Charon, C#.62, GA Tech “Hey, these status reports are kinda useful.” udp

4 October, 2007CCSDS DTN BoF -- Heppenheim20 Features Tested at IETF67 End-to-end transmission –With and without custody transfer –Moving between convergence layers Payload sizes varying from 6 to 1545 bytes –Raw text messages – -format messages destined for Symbian phone All status reports generated and parsed –Report-to different from source endpoint Partial test of TTL expiration

4 October, 2007CCSDS DTN BoF -- Heppenheim21 DTN Convergence Layers TCP/UDP –DTN2 Reference Implementation LTP –draft-irtf-dtnrg-ltp-06 –draft-irtf-dtnrg-ltp-extensions-05 –draft-irtf-dtnrg-ltp-motivation-05

4 October, 2007CCSDS DTN BoF -- Heppenheim22 Bundle Protocol Headers (Blocks) Creation Stamp1 VersionFlags Block length Destination Scheme Destination SSP Source Scheme Source SSP Report-to Scheme Report-to SSP Custodian scheme Custodian SSP Creation Stamp2 Lifetime Dictionary Length Dictionary (Variable) Fragment Offset Total ADU length Bundle Protocol Headers Block Type Primary Bundle Block Control Flags Block Length Payload Bundle Payload Block 32 bits CBHE Compressed Bundle Header Encoding Creation Stamp1 VersionFlags Block length Scheme Number Destination Element # Destination Service # Source Element # Source Service # Report-to Element # Report-to Service # Custodian Element # Creation Stamp2 Lifetime Fragment Offset Total ADU length Block Type Primary Bundle Block Control Flags Block Length Payload Bundle Payload Block Dictionary Length=0 32 bits Dictionary allows references to address information that may occur multiple times (e.g. src. and dst. schemes the same; src and report-to endpoints the same). Dashed boxes are SDNVs.

4 October, 2007CCSDS DTN BoF -- Heppenheim23 DTN Activities NASA effort to demonstrate flight-ready DTN by 2010 –Target of TRL 8 by 2010 Active research community –Testing the protocol –Maintaining multiple interoperable implementations –Developing additional capabilities ‘Space-Oriented’ Implementation and Applications –ION Implementation –Remote AMS over DTN

4 October, 2007CCSDS DTN BoF -- Heppenheim24 How DTN Might Fit Within CCSDS: Architectures and Interoperability Slides with strawman architectures and interoperability points

Downlink Set

4 October, 2007CCSDS DTN BoF -- Heppenheim26 Strawman DTN Architecture Downlink Remote Element Prox-1 DTN Remote Relay Prox-1 Ground Station Control Center DTN AOS X-Support Xfer Svcs AOSEther IP TCP Application Terrestrial X-Support 1 Deep-Space X-Support Relay X-Support Agency AAgency BAgency CAgency A Space Packets Space Pkts Space Pkts Minimal DTN deployment No additional interoperability requirements beyond current plans

4 October, 2007CCSDS DTN BoF -- Heppenheim27 Strawman DTN Architecture Downlink Remote Element Prox-1 DTN Remote Relay Prox-1 DTN Ground Station Control Center DTN AOS X-Support Xfer Svcs AOSEther IP TCP Application Terrestrial X-Support 1 Deep-Space X-Support Relay X-Support Agency AAgency BAgency CAgency A Space Packets Space Pkts Space Pkts DTN in relay orbiter Significant performance increase

4 October, 2007CCSDS DTN BoF -- Heppenheim28 DTN Strawman DTN Architecture Downlink Remote Element Prox-1 DTN Remote Relay Prox-1 DTN Ground Station DTN Control Center DTN Terr. User AOS X-Support Xfer Svcs AOSEther IP TCP Ether IP TCP Application Terrestrial X-Support 1 Deep-Space X-Support Relay X-Support Agency AAgency BAgency CAgency DAgency A Space Packets Space Pkts Space Pkts Space Pkts Terrestrial X-Support 2 Fully deployed DTN Additional terrestrial interoperability shown

Uplink Set

4 October, 2007CCSDS DTN BoF -- Heppenheim30 Strawman DTN Architecture Uplink Remote Element Prox-1 DTN Remote Relay Prox-1 Ground Station Control Center DTN TC X-Support Xfer Svcs TC CLTUs Ether IP TCP Application Terrestrial X-Support 1 Deep-Space X-Support Relay X-Support Agency AAgency BAgency CAgency A Space Packets Space Pkts Space Pkts Minimal DTN over TC deployment No additional interoperability requirements beyond current plans

4 October, 2007CCSDS DTN BoF -- Heppenheim31 Strawman DTN Architecture Uplink Remote Element Prox-1 DTN Remote Relay Prox-1 DTN Ground Station Control Center DTN TC X-Support Xfer Svcs TC CLTUs Ether IP TCP Application Terrestrial X-Support 1 Deep-Space X-Support Relay X-Support Agency AAgency BAgency CAgency A Space Packets Space Pkts Space Pkts DTN at remote relay

4 October, 2007CCSDS DTN BoF -- Heppenheim32 DTN Strawman DTN Architecture Uplink Remote Element Prox-1 DTN Remote Relay Prox-1 DTN Ground Station DTN Control Center DTN Terr. User TC X-Support Xfer Svcs TC CLTUs Ether IP TCP Ether IP TCP Application Terrestrial X-Support 1 Deep-Space X-Support Relay X-Support Agency AAgency BAgency CAgency DAgency A Space Packets Space Pkts Space Pkts Space Pkts Terrestrial X-Support 2 Fully deployed DTN Additional terrestrial interoperability shown DTN boundaries can be security boundaries; control center checking

4 October, 2007CCSDS DTN BoF -- Heppenheim33 Conclusions Orbiter-Landed element interoperability is necessary but additional features are needed –Packets by themselves don’t provide reliability, mutli-packet ADU, or accountability –CFDP provides many but not all of these features under a ‘file- specific’ model DTN generalizes CFDP functionality by refactoring it into its constituent parts (LTP, DTN, Application) and adds additional capabilities –More useful for SMC? CCSDS can leverage work done by the DTN community –Demonstrated interoperability –Protocol extensions

Backup

4 October, 2007CCSDS DTN BoF -- Heppenheim35 Registered Participants Last NameFirst NameAgency BlanchetMarcViagenie / BurleighScottNASA / DurstRobertNASA / The MITRE EdwardGreenbergNASA / GannettThomasNASA / HellWolfgangESA / IsraelDavidNASA / KearneyMikeNASA MarquartJaneNASA / OttJörgHelsinki University of PittsR. LeeNASA / ScottKeithNASA / The MITRE StantonDaiKeltik / TsaoussidisVassilisDemokritus University of

4 October, 2007CCSDS DTN BoF -- Heppenheim36

4 October, 2007CCSDS DTN BoF -- Heppenheim37

4 October, 2007CCSDS DTN BoF -- Heppenheim38 Initial DTN Performance Tests

4 October, 2007CCSDS DTN BoF -- Heppenheim39 Draft WG Deliverables (From Group Discussion) DTN Green Book –Architecture Compatibility w/ existing systems –Relationship between DTN and CFDP –Ops concepts JAXA conops (source apps and time) – data recorder design –Mission Scenarios –Section on routing requirements / ideas or separate document on routing requirement s / ideas (no protocol book) DTN bundle protocol (Blue Book) LTP protocol (Blue Book)