© 2004 The MITRE Corporation. All rights reserved Cislunar WG CCSDS Toulouse November 2004

© 2004 The MITRE Corporation. All rights reserved Cislunar Goals n Create a top-level architecture and operations concept for communicating effectively over the whole range of cislunar distances. n Review current and emerging CCSDS standards and recommend any updates required to keep them current. n Examine the spectrum of new Internet development activities that are proceeding, and identify where they may be applicable to cislunar n Recommend standards for cislunar communications. n Define architecture that handles: –Voice/video (realtime and non-realtime) –Data (realtime and non-realtime) n Between Earth and Moon (RTT ~2.5s) n Extensible to Mars (RTT ~ minutes)

© 2004 The MITRE Corporation. All rights reserved Cislunar Activities n Green book describing –Architecture –Operations Concept n Interface with C3I activity n Paper describing candidate protocols n Review of applicable CCSDS Protocols –SCPS-TP Updates

© 2004 The MITRE Corporation. All rights reserved Starting from… Treat CCSDS channel access services as interfaces to IP

© 2004 The MITRE Corporation. All rights reserved And recognizing ongoing work in the IETF… n The Stream Control Transmission Protocol SCTP. n The Datagram Congestion Control Protocol (DCCP). n Voice Over IP (VOIP). n Disruption Tolerant Networking (DTN). n LEMONADE enhancements to Internet to support diverse service environments. n Internet over Digital Broadcast Video Networks.

© 2004 The MITRE Corporation. All rights reserved IP-Based Communications Architecture n Single packet-switched network carrying: –Voice (over IP) –data –HDTV n Quality of Service –Protect life-critical and mission-critical data from congestion –QoS options (not mutually exclusive) n Manually set up class-based queueing classes n Integrated Services n Differentiated Services n Standard IP TOS

© 2004 The MITRE Corporation. All rights reserved “Draft Green Book” n More a compendium of tools with some rationale for why they’re needed n Needs –Architecture –Use cases / scenarios to beat the architecture against

© 2004 The MITRE Corporation. All rights reserved Review current and emerging CCSDS standards n A number of vendors are selling SCPS-TP-based Performance Enhancing Proxies (PEPs) n SIS-SCPS-INTEREST mailing list started to get vendor inputs –All the major SCPS vendors that I know of are on the list –Active discussion of SCPS-TP n Clarifications to improve interoperability n Possible extensions to address specific needs

© 2004 The MITRE Corporation. All rights reserved QoS Option: Manually set up CBQ classes n Class-based queueing can define traffic classes and specify bandwidth allocations –Classes generally defined by source & destination IP addresses, ports, and transport protocol n If the CBQ classes are instantiated administratively in all routers, there’s no setup time –Critical traffic gets priority, period

© 2004 The MITRE Corporation. All rights reserved QoS Option: Integrated Services (intserv) n Intserv provides per-Flow resource reservations –Flow is defined by the 5-tuple (src IP, dst IP, protocol, dest port) –Token-bucket type reservations (bucket size, token rate) –Interaction between applications and network –Resource reSerVation Protocol (RSVP) for signaling n Two flavors of integrated services –Controlled load service (RFC2211): provide performance similar to that of an unloaded network –Guaranteed service (RFC2212): guarantees that packets will arrive within a certain time and will not be discarded because of queue overflows

© 2004 The MITRE Corporation. All rights reserved QoS Option: Differentiated Services (diffserv) n Uses 6 bits of the IP Type of Service (TOS) byte as diffserv code point (DSCP) –Expedited Forwarding –4 assured forwarding classes, each containing three drop precedence n All traffic with the same DSCP treated the same way n Needs other infrastructure (admission control, bandwidth brokers) to ensure that the system can meet QoS expectations of specific DSCPs

© 2004 The MITRE Corporation. All rights reserved Dealing with Latency n Latency will affect performance of Internet protocols (particularly TCP), even at cislunar distances –Transport layer proxies –Application layer proxies

© 2004 The MITRE Corporation. All rights reserved Dealing with Disconnection n Disconnection can cause problems at cislunar (unless continuous coverage) and at interplanetary distances –Application layer proxies –Delay Tolerant Networking Application Bundle Transport Network Transport Network Bundle Transport Network Bundle Application Bundle Transport Network Bundle

© 2004 The MITRE Corporation. All rights reserved To do… n The rest of the architecture –Operations concept –Scenarios & examples n Recommend Standards –Review / update CCSDS standards

© 2004 The MITRE Corporation. All rights reserved n Applications signal data requirements to the network n Network responds (yes/no) –If yes, network provisions the path  prevents congestion loss n Standardized RSVP extensions for protocol translating gateways Internet RSVP

© 2004 The MITRE Corporation. All rights reserved QoS Option: Integrated Services (intserv) n Intserv provides per-Flow resource reservations –Flow is (src IP, dst IP, protocol, dest port) –Token-bucket type reservations (bucket size, token rate) –Interaction between applications and network n Applications reserve resources (bandwidth) by making specific calls that include the destination IP address and port, e.g.: rapi_sid_t rapi_session( rapi_addr_t *Dest,[IP address and port of destination] int Protid,[Protocol, e.g. TCP/UDP] unsigned int flags, rapi_event_return_t *Event_rtn, void *Event_arg, int *errnop ); –RSVP PATH messages travel source->destination HOP by HOP and are processed at EACH ROUTER (router alert IP option) –RSVP RESV messages follow the reverse path with destination’s request n Proxies can snoop traffic and generate reservations on behalf of applications, or can preemptively set up reservations on behalf of applications –Caveat: proxies have to be in the data path of the endpoints (you can only reserve resources between you and the destination) n RSVP does NOT flow across autonomous system (AS) boundaries in the Internet

© 2004 The MITRE Corporation. All rights reserved n Guaranteed Service (RFC 2212) –For applications requiring fixed delay bound and a bandwidth guarantee –Control the maximum queuing delay –Guarantees that packets will arrive within a certain time and will not be discarded because of queue overflows –No control on minimal or average delay (what about jitter?) –No packet fragmentation is allowed. –Guaranteed service is invoked by a sender specifying a traffic descriptor (Tspec) and a service specification (Rspec) n Rspec has two parameters: Service rate ( R ) and Slack Term ( S)

© 2004 The MITRE Corporation. All rights reserved –Worst case queuing delay for guaranteed service: ((b-M)(p-R)) / (R (p-r)) + (M+Ctot)/R + Dtot if p>R>=r (M+Ctot) / R + Dtot if (R >=p >= r)

© 2004 The MITRE Corporation. All rights reserved n Controlled load service (RFC 2211) –Provides unloaded network conditions n Closely approximates traditional best-effort in a lightly loaded or unloaded network environment –Intended for adaptive applications –Priority service with admission control –No fragmentation, packets must comply to MTU

© 2004 The MITRE Corporation. All rights reserved QoS Option: Diffserv with Bandwidth Brokers n Bandwidth brokers provide admission control for diffserv –Ensure not only differentiated service, but maintain a minimum quality of service for privileged flows

© 2004 The MITRE Corporation. All rights reserved Evolution of Protocols for Cislunar Exploration n Latency will degrade the performance of, and finally prevent the use of, standard Internet protocols –One-way latencies up up to ~2s probably tolerable n Evolution of protocols to deal with high latencies –COTS Protocols (TCP/IP) n Works for ‘low-stress environments) –COTS + Mitigations n Transport layer (TCP) proxies n Application layer proxies –DTN n A different API to applications n Provides communications even when no end-to-end path exists

© 2004 The MITRE Corporation. All rights reserved