The Interplanetary Internet Challenges for the Internet's Evolution

1. The Interplanetary Internet Challenges for the Internet's Evolution TERENA Networking Conference 2000 24 May 2000 Scott Burleigh, Vint Cerf Bob Durst, Adrian Hooke Keith Scott, Eric Travis, Howard Weiss

5. A Candidate Sharing of Issues and Technologies Moon Mars Earth • Generally high bandwidth-delay products • Possible data loss due to bit-errors and/or transient link outages • Potentially asymmetric data rates Surface to Orbit Relay Satellite, Wireless • Power constrained end systems • Episodic/disjoint connectivity • Networks may need to be self-organizing Mobile/ Roving applications Surface Operations • Channels often periodically unidirectional • Need for progressive/selectable reliability • Need for store-and-forward delivery Long Haul to Earth • Ultra high bandwidth-delay product • typically >> transaction size • ‘Ping-pong of bursts’ replaces streaming Internet backbone

7. Deploy standard internets in low latency remote environments (e.g., on or around remote rocks) Connect distributed internets via an interplanetary backbone that handles the high latency deep space environment. Create gateways and relays to interface between low and high latency environments The Basic IPN Concept:Construct a “Network of internets”

8. i i i I i IG i i IG i I IG i Inter-Internet Dialog and Nodes Interplanetary Gateways I i i i i Security luna.sol mars.sol Deployed Internets Stable Backbone i I IG IG i i IG i i i i IPN Technology Thrust Areas earth.sol I Wired Tetherless i

10. The Good News Is ... Much of the ongoing work in terrestrial mobile ad hoc networking is interesting, relevant, and timely We can probably apply these emerging terrestrial technologies to our in-situ space communications needs, rather than developing them from scratch But… Anything deployed on remote rocks is going to be slow to evolve

11. A set of high-capacity, high-availability links between network traffic hubs Terrestrial backbone links are between hubs like Lisbon and Paris. Interplanetary backbone links are between hubs like Europa and Mars. Availability is a matter of perspective... Inter-Internet Dialog and Nodes Interplanetary Gateways Security Deployed Internets Stable Backbone What’s a Backbone?

12. Terrestrial Backbone Interplanetary Backbone Delay (light sec) < .1 10 to 10,000 Wired Untethered, moving Connectivity Medium Copper, glass Space Deployment $ “low” Very high High (power is costly) “low” Operations $ Repair, upgrade $ “low” Very high Differences Between Terrestrial and Interplanetary Backbones

13. Communications capacity is expensive Bits count Round Trips hurt Interactive protocols don’t work Internet protocol suite doesn’t scale well with increasing latency Negotiation is impractical Reliable in-order delivery takes too long Protocols need to be connectionless Congestion control and flow control are difficult Reliance on forward coding versus retransmission for error recovery Custody, store-and-forward data transfer is fundamental “Chatty Telephony” gives way to “Bundled Mail” as the model of operations On the Interplanetary Backbone:

14. Communication in a Micro-Power Environment: It's a Full-Stack Job • Link Layer: • Effects of very low SNRs in conjunction with QOS • Multiple simultaneous coding schemes needed? • Resource reservation/interference avoidance • Signaling of link status to upper layers: • availability; capacity and congestion status; error status • Network Layer: • MANETs with both fast- and slow-moving elements • Changing resource availability • Synthesis and propagation of link status • Resource allocation: integrated services?, adaptive • Self organization

15. Communicating in a Micro-Power Environment: It's a Full-Stack Job • Transport Layer: • Power-efficiency requires careful balance between link layer • coding and transport layer retransmission • Adaptive to changing network conditions • QOS-responsive • Tolerant of link outages and mixed losses • Application Layer: • Service location in infrastructure-free environment • Efficient network management and control • Health and status of mobile nodes (not just networking aspects)

16. The IPN is really about exploring the evolutionary paths the Internet may take as the dynamic range of interconnected environments continues to increase... Autonomy - functional and/or administrative Mobility - not just nodes, but entire networks Impedance Matching - keeping the backbone fair, but allowing subnets to be aggressive While preserve the end-to-end semantics of communications While communications with distant rocks can be exciting...

17. Bundle Space Network of internets spanning dissimilar environments Application Application Bundle Bundle Bundle Bundle Transport Transport Transport Transport Network Network Network Network Bundle space supports end-to-end transfer across IPN domains and/or heterogeneous network protocol stacks

18. Names are the means of reference Routing between domains based upon names Late-Binding Separate addressing domains for each internet; names converted to local addresses in destination domain Indirection Inherent dependence on intermediate relay agents Custodial transfer “Bundles” as a common end-to-end mailing mechanism Inter-Internet Dialog and Nodes Interplanetary Gateways Security Deployed Internets Stable Backbone Inter-Internet Dialog: Design Principles

19. Traffic is inherently non-interactive A single self-contained request generates a single self-contained response Distinctly taciturn, “non-chatty” dialog Bundling Protocol lives above the local transport protocols, but below end-to-end applications Minimally, carries names end-to-end in “metadata” Potential applicability to new Internet applications Inter-Internet Dialog and Nodes Interplanetary Gateways Security Deployed Internets Stable Backbone Bundled Data Transfers

20. Single Name Space,Late Name-to-Address Binding(s) Name Space - Common Across All Internets Name-to-Address Binding Space B Name-to-Address Binding Space C Name-to-Address Binding Space A Interplanetary Backbone Internet Internet .earth.sol .ipn.sol .mars.sol http://www.bughunter.org.earth.sol 137.79.10.232 http://www.rockshop.com.mars.sol 137.79.10.232

21. Custody Transfers “Shipping Receipt and Tracking #” Interplanetary Backbone Internet Internet R G R A A G G “Return Receipt” A Bundle Agent: builder and consumer of bundles IPN Gateway: custody transfer and routing between IPN domains G R • IPN Relay: mitigation for R2 effects; no custody transfer From Telephony Back to the Pony ExpressCustody Transfers and Bundles

23. i i i I i Inter-Internet Dialog and Nodes Interplanetary Gateways i i i Security I i I Deployed Internets Stable Backbone i i i i i I i i i i i IPN Security Security of user data flowing through the IPN earth.sol IG IG IG luna.sol mars.sol Security of the IPN backbone IG IG i IG

24. access control to the IPN will be required because space-based assets will have limited available resources. authentication will be required to perform access controls. data integrity will be required to assure that what was sent is received. data privacy will be required to assure that unauthorized users cannot obtain information. IPN Security Requirements

25. IPN Security Constraints • We can only have end-to-end security where • there are end-to-end protocols, so: • - security cannot be performed in the IPN at transport or below IPSEC • In the IPN, end-to-end protocols (e.g. TCP) are • terminated at the IPN gateways • . • End-to-end like security can only be applied • to the data(e.g.,TLS/SSL, S/email) • - is TLS/SSL the right answer (many round-trip negotiations)? NO! • - is secure email model is a better fit? YES • - key management - “PKI to the Planets?”

27. Mars may need women, but... The IPN Needs Participants Help expand the gene pool: Robert Rumeau (CNES) Centre National d'Etudes Spatiales Toulouse CEDEX Rumeau@cnes.fr Eric Travis (NASA) Global Science and Technology, Inc. Greenbelt, Maryland 20770 USA travis@gst.com (Dinosaurs Welcome; Spacecraft optional)