Cislunar BOF 5/14/2004 Montreal

Goals for Today ● Problem Definition ● Gauge Interest ● Outline Working Group Charter ● Assess Resources

0800 –Description of BOF / Agenda Bashing 0810 –Cislunar and In-situ Communications Overview 0820 –Goals of a Cislunar Working Group Issues / Presentations 0830 – Requirements 0845 – SCPS-TP 0915 – CFDP 0945 – Delay Tolerant Networking 1015 – Brief survey of other technologies 1030 –Open mike for other issues 1100 –Interest Straw Poll 1110 –Discussions of the way forward: Draft Charter Possible work items Schedule 1200 –Adjourn

Definitions ● Cislunar – adj: situated between the Earth and the Moon ● In-Situ – adj: being in the original position; not having been moved; "the archeologists could date the vase because it was in situ"; "an in-situ investigator" [syn: unmoved] – In-situ communications: communications between physically proximate endpoints

Motivation ● Increased interest in human and robotic exploration of the Moon and Mars ● Near-Earth comms: can be “Internet-like” ● Deep-Space: TC / TM, CFDP, DTN ● What about lunar distances? (~2.5 sec RTT) – End-to-End TCP falls over – SCPS-TP works OK, gateways improve performance ● Application performance will vary – Human exploration adds new requirements – Very high rate, voice/video (HDTV), reliability, availability

Goals of a Cislunar Working Group (1/2) ● Determine requirements of possible new Lunar exploration programs and their mapping into similar capabilities that will be needed on and around Mars – Products: Yellow Book on cislunar / Mars comm. requirements ● Create a top-level operations concept for communicating effectively over the whole range of cislunar distances – Products: Green Book for Cislunar Communication

Goals of a Cislunar Working Group (2/2) ● Review existing capabilities (CCSDS space internetworking standards, other standardization groups (such as the IETF)) – Products: Yellow Book on existing communications capabilities Updates to existing standards (pink sheets) ● Protocol development if needed – Products: Blue Book(s) describing protocols for cislunar communications

Requirements? ● Voice ● Videoconference ● HDTV downlink ● Operation in intermittently-connected environments? ● Tele-operation of robots WASHINGTON (CNN) -- Saying "the desire to explore and understand is part of our character," President Bush Wednesday unveiled an ambitious plan to return Americans to the moon by 2020 and use the mission as a steppingstone for future manned trips to Mars and beyond.

Existing Capabilities DTN CFDP SCPS-TP

Brief Survey of Related Technologies

IETF LEMONADE Lemonade is tasked to provide a set of enhancements and profiles of Internet submission, transport, and retrieval protocols to facilitate operation on platforms with constrained resources, or communications links with high latency or limited bandwidth. A primary goal of this work is to ensure that those profiles and enhancements continue to interoperate with the existing Internet protocols in use on the Internet, so that these environments and more traditional Internet users have access to a seamless service.

IETF IP-over-DVB The WG will develop new protocols and architectures to enable better deployment of IP over MPEG-2 transport and provide easier interworking with IP networks. Specific properties of this subnetwork technology include link-layer support for unicast and multicast, large numbers of down-stream receivers, and efficiency of transmission.

DVB-S ● Possibility of signaling link changes (coding, data rate,...)

IETF Datagram Congestion Control Protocol (dccp) The Datagram Control Protocol working group is chartered to develop and standardize the Datagram Congestion Control Protocol (DCCP). DCCP is a minimal general purpose transport-layer protocol providing only two core functions: – the establishment, maintenance and teardown of an unreliable packet flow. – congestion control of that packet flow.

IETF SCTP (RFC2960) ● SCTP is a reliable transport protocol operating on top of a connectionless packet network such as IP. It offers the following services to its users: – acknowledged error-free non-duplicated transfer of user data, – data fragmentation to conform to discovered path MTU size – sequenced delivery of user messages within multiple streams, with an option for order-of-arrival delivery of individual user messages – optional bundling of multiple user messages into a single SCTP packet – network-level fault tolerance through supporting of multi-homing at either or both ends of an association. ● The design of SCTP includes appropriate congestion avoidance behavior and resistance to flooding and masquerade attacks.

Middlebox Architectures ● IETF midcom working group – As trusted third parties are increasingly being asked to make policy decisions on behalf of the various entities participating in an application's operation, a need has developed for applications to be able to communicate their needs to the devices in the network that provide transport policy enforcement. Examples of these devices include firewalls, network address translators (both within and between address families), signature management for intrusion detection systems, and multimedia buffer management. These devices are a subset of what can be referred to as 'middleboxes.' ● SCPS-TP Gateways

Interest Straw Poll

Possible Work Items ● Green book describing operations concept ● Yellow book describing requirements for cislunar and Mars in-situ environments ● Yellow book assessing existing capabilities ● Pink sheets updating existing CCSDS protocols ● Blue / Orange books for any new protocols identified / developed

Cislunar Mailing List MAILING (sign up through bin/mailman/listinfo/sis-csi) bin/mailman/listinfo/sis-csi Will put draft charter on docushare.

Draft Charter

End of presentation.

BACKUP

Some Data Points ● Earth-Moon distance is 384,748 km (~1.28s one-way) ● Earth-Mars distance varies between ~4 minutes and ~20 minutes (one-way)

SCPS-TP ● Extensions to TCP that provide – Record boundaries – Selective Negative Acknowledgements (SNACKs) ● Specification of alternate congestion control mechanisms – Vegas congestion control, rate control ● Needed Additions – SACK, ECN, Ipv6, DVB-RCS (coordination/session) – Signaled payload compression?