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Lochin, Ed. 5 Expires: June 14, 2019 ISAE-SUPAERO 6 Dec 11, 2018 8 Network coding and satellites 9 draft-irtf-nwcrg-network-coding-satellites-03 11 Abstract 13 This memo details a multi-gateway satellite system to identify 14 multiple opportunities on how coding techniques could be deployed at 15 a wider scale. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at https://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on June 14, 2019. 34 Copyright Notice 36 Copyright (c) 2018 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (https://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 1.1. Glossary . . . . . . . . . . . . . . . . . . . . . . . . 3 53 1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4 54 2. A note on satellite topology . . . . . . . . . . . . . . . . 4 55 3. Actual deployment of reliability schemes in satellite systems 6 56 4. Details on the use cases . . . . . . . . . . . . . . . . . . 6 57 4.1. Two-way relay channel mode . . . . . . . . . . . . . . . 7 58 4.2. Reliable multicast . . . . . . . . . . . . . . . . . . . 7 59 4.3. Hybrid access . . . . . . . . . . . . . . . . . . . . . . 8 60 4.4. Dealing with varying capacity . . . . . . . . . . . . . . 9 61 4.5. Improving the gateway handovers . . . . . . . . . . . . . 10 62 5. Research challenges . . . . . . . . . . . . . . . . . . . . . 10 63 5.1. Towards an increased deployability in SATCOM systems . . 10 64 5.2. Interaction with virtualization . . . . . . . . . . . . . 11 65 5.3. Delay/Disruption Tolerant Networks . . . . . . . . . . . 11 66 6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 12 67 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 68 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 69 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 70 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 71 10.1. Normative References . . . . . . . . . . . . . . . . . . 12 72 10.2. Informative References . . . . . . . . . . . . . . . . . 13 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 75 1. Introduction 77 Guaranteeing both physical layer robustness and efficient usage of 78 the radio resource has been in the core design of SATellite 79 COMmunication (SATCOM) systems. The trade-off often resided in how 80 much redundancy a system adds to cope from link impairments, without 81 reducing the good-put when the channel quality is high. There is 82 usually enough redundancy to guarantee a Quasi-Error Free 83 transmission. However, physical layer reliability mechanisms may not 84 recover transmission losses (e.g. with a mobile user) and layer 2 (or 85 above) re-transmissions induce 500 ms one-way delay with a 86 geostationary satellite. Further exploiting coding schemes at higher 87 OSI-layers is an opportunity for releasing constraints on the 88 physical layer in such cases and improving the performance of SATCOM 89 systems. 91 We have noticed an active research activity on coding and SATCOM in 92 the past. That being said, not much has actually made it to 93 industrial developments. In this context, this document aims at 94 identifying opportunities for further usage of coding in these 95 systems. 97 This document follows the taxonomy of coding techniques for efficient 98 network communications [RFC8406]. 100 1.1. Glossary 102 The glossary of this memo extends the glossary of the taxonomy 103 document [RFC8406] as follows: 105 o ACM : Adaptative Coding and Modulation; 107 o BBFRAME: Base-Band FRAME - satellite communication layer 2 108 encapsulation work as follows: (1) each layer 3 packet is 109 encapsulated with a Generic Stream Encapsulation (GSE) mechanism, 110 (2) GSE packets are gathered to create BBFRAMEs, (3) BBFRAMEs 111 contain information related to how they have to be modulated (4) 112 BBFRAMEs are forwarded to the physical layer; 114 o CPE: Customer Premise Equipment; 116 o DTN: Delay/Disruption Tolerant Network; 118 o DSL: Digital Subscriber Line; 120 o LTE: Long Term Evolution; 122 o SAT: SATellite; 124 o EPC: Evolved Packet Core; 126 o ETSI: European Telecommunications Standards Institute; 128 o PEP: Performance Enhanced Proxy - a typical PEP for satellite 129 communications include compression, caching and TCP acceleration; 131 o PLFRAME: Physical Layer FRAME - modulated version of a BBFRAME 132 with additional information (e.g. related to synchronization); 134 o SATCOM: generic term related to all kind of SATellite 135 COMmunications systems; 137 o QoS: Quality-of-Service; 139 o QoE: Quality-of-Experience; 141 o VNF: Virtualized Network Function. 143 1.2. Requirements Language 145 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 146 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 147 document are to be interpreted as described in RFC 2119 [RFC2119]. 149 2. A note on satellite topology 151 This section focuses on a generic description of the components 152 composing a generic satellite system and their interaction. A high 153 level description of a multi-gateway satellites network is provided. 154 There are multiple SATCOM systems, such as those dedicated to 155 broadcasting TV or to IoT applications: depending on the purpose of 156 the SATCOM system, ground segments are specific. This memo lays on 157 SATCOM systems dedicated to broadband Internet access that follows 158 the DVB-S2/RCS2 standards. In this context, the increase of the 159 available capacity that is carried out to end users and reliability 160 requirements lead to multiple gateways for one unique satellite 161 platform. 163 In this context, Figure 1 shows an example of a multi-gateway 164 satellite system. In a multi-gateway system, some elements may be 165 centralized and/or gathered: the relevance of one approach compared 166 to another depends on the deployment scenario. More information on 167 these discussions and a generic SATCOM ground segment architecture 168 for a bi-directional Internet access can be found in [SAT2017]. 170 Some functional blocks aggregate the traffic of multiple users. 171 Coding schemes could be applied on both single and aggregated 172 traffic. 174 +---------------------+ 175 | application servers | 176 +---------------------+ 177 ^ ^ 178 | ... | 179 ----------------------------------- 180 v v v v v v 181 +------------------+ +------------------+ 182 | network function | | network function | 183 | (firewall, PEP) | | (firewall, PEP) | 184 +------------------+ +------------------+ 185 ^ ^ ^ ^ 186 | ... | IP packets | ... | 187 v v v v 188 +------------------+ +------------------+ 189 | access gateway | | access gateway | 190 +------------------+ +------------------+ 191 ^ ^ 192 | BBFRAMEs | 193 v v 194 +------------------+ +------------------+ 195 | physical gateway | | physical gateway | 196 +------------------+ +------------------+ 197 ^ ^ 198 | PLFRAMEs | 199 v v 200 +------------------+ +------------------+ 201 | outdoor unit | | outdoor unit | 202 +------------------+ +------------------+ 203 ^ ^ 204 | satellite link | 205 v v 206 +------------------+ +------------------+ 207 | sat terminals | | sat terminals | 208 +------------------+ +------------------+ 209 ^ ^ ^ ^ 210 | ... | | ... | 211 v v v v 212 +------------------+ +------------------+ 213 | end user | | end user | 214 +------------------+ +------------------+ 216 Figure 1: Data plane functions in a generic satellite multi-gateway 217 system 219 3. Actual deployment of reliability schemes in satellite systems 221 Figure 2 presents the status of the reliability schemes deployment in 222 satellite systems. The information is based on the taxonomy document 223 [RFC8406] and the notations are the following: End-to-End Coding 224 (E2E), Network Coding (NC), Intra-Flow Coding (IntraF), Inter-Flow 225 Coding (InterF), Single-Path Coding (SP) and Multi-Path Coding (MP). 227 X1 embodies the source coding that could be used at application level 228 for instance within QUIC or other video streaming applications. This 229 is not specific to SATCOM systems since such deployment can be 230 relevant for broadband Internet access discussions. 232 X2 embodies the physical layer, applied to the PLFRAME, to optimize 233 the satellite capacity usage. At the physical layer, FEC mechanisms 234 can be exploited. This aspect is not in the scope of the WG 235 according to the taxonomoy document [RFC8406]. 237 +------+-------+---------+---------------+-------+ 238 | | Upper | Middle | Communication layers | 239 | | Appl. | ware | | 240 + +-------+---------+---------------+-------+ 241 | |Source | Network | Packetization | PHY | 242 | |coding | AL-FEC | UDP/IP | layer | 243 +------+-------+---------+---------------+-------+ 244 |E2E | X1 | | | | 245 |NC | | | | | 246 |IntraF| X1 | | | | 247 |InterF| | | | X2 | 248 |SP | X1 | | | X2 | 249 |MP | | | | | 250 +------+-------+---------+---------------+-------+ 252 Figure 2: Reliability schemes in current satellite systems 254 Reliability is an inherent part of the physical layer and usually 255 achieved by using coding techniques. Based on public information, 256 coding does not seem to be widely used at higher layers. 258 4. Details on the use cases 260 This section details use-cases where coding schemes could improve the 261 overall performance of a SATCOM system (e.g. considering a more 262 efficient usage of the satellite resource, delivery delay, delivery 263 ratio). 265 It is worth noting that these use-cases mostly focus on the 266 middleware and packetization UDP/IP of Figure 2. There are already 267 lots of recovery mechanisms at the physical layer in currently 268 deployed systems while E2E source coding are done at the application 269 level. In a multi-gateway SATCOM Internet access, the deployment 270 opportunities are more relevant in specific SATCOM components such as 271 the "network function" block or the "access gateway" of Figure 1. 273 4.1. Two-way relay channel mode 275 This use-case considers a two-way communication between end users, 276 through a satellite link. Figure 3 proposes an illustration of this 277 scenario. 279 Satellite terminal A (resp. B) transmits a flow A (resp. B) to a NC 280 server, which forwards a combination of both terminal flows. This 281 results in non-negligible capacity savings and has been demonstrated 282 [ASMS2010]. Moreover, with On-Board Processing satellite payloads, 283 the coding operations could be done at the satellite level, thus 284 reducing the end-to-end delay of the communication. 286 -X}- : traffic from satellite terminal X to the server 287 ={X+Y= : traffic from X and Y combined transmitted from 288 the server to terminals X and Y 290 +-----------+ +-----+ 291 |Sat term A |--A}-+ | | 292 +-----------+ | | | +---------+ +------+ 293 ^^ +--| |--A}--| |--A}--| | 294 || | SAT |--B}--| Gateway |--B}--|Server| 295 ===={A+B=========| |={A+B=| |={A+B=| | 296 || | | +---------+ +------+ 297 vv +--| | 298 +-----------+ | | | 299 |Sat term B |--B}-+ | | 300 +-----------+ +-----+ 302 Figure 3: Network architecture for two way relay channel with NC 304 4.2. Reliable multicast 306 Using multicast servers is a way to better exploit the satellite 307 broadcast capabilities. This approach is proposed in the SHINE ESA 308 project [I-D.vazquez-nfvrg-netcod-function-virtualization] [SHINE]. 309 This use-case considers adding redundancy to a multicast flow 310 depending on what has been received by different end-users, resulting 311 in non-negligible scarce resource saving. We propose an illustration 312 for this scenario in Figure 4. 314 A multicast flow (M) is forwarded to both satellite terminals A and 315 B. However packet Ni (resp. Nj) get lost at terminal A (resp. B), 316 and terminal A (resp. B) returns a negative acknowledgement Li 317 (resp. Lj), indicating that the packet is missing. Then either the 318 access gateway or the multicast server includes a repair packet 319 (rather than the individual Ni and Nj packets) in the multicast flow 320 to let both terminals recover from losses. This could be achieved by 321 using NACK-Oriented Reliable Multicast (NORM) [RFC5740] in situations 322 where a feedback link is available, or FLUTE/ALC [RFC6726] otherwise. 323 Note that both NORM and FLUTE/ALC are limited to block coding, none 324 of them supporting sliding window encoding schemes [RFC8406]. 326 -Li}- : packet indicating the loss of packet i of a multicast flow M 327 ={M== : multicast flow including the missing packets 329 +-----------+ +-----+ 330 |Sat term A |-Li}-+ | | 331 +-----------+ | | | +---------+ +------+ 332 ^^ +-| |-Li}--| | |Multi | 333 || | SAT |-Lj}--| Gateway |--|Cast | 334 ===={M==========| |={M===| | |Server| 335 || | | +---------+ +------+ 336 vv +-| | 337 +-----------+ | | | 338 |Sat term B |-Lj}-+ | | 339 +-----------+ +-----+ 341 Figure 4: Network architecture for a reliable multicast with NC 343 4.3. Hybrid access 345 This use-case considers the use of multiple path management with 346 coding at the transport level to increase the reliability and/or the 347 total capacity (using multiple path does not guarantee an improvement 348 of both the reliability and the total capacity). We propose an 349 illustration for this scenario in Figure 5. This use-case is 350 inspired from the Broadband Access via Integrated Terrestrial 351 Satellite Systems (BATS) project and has been published as an ETSI 352 Technical Report [ETSITR2017]. This kind of architecture is also 353 discussed in the TCPM working group [I-D.ietf-tcpm-converters]. 355 To cope with packet loss (due to either end-user mobility or physical 356 layer impairments), coding could be introduced in both the CPE and at 357 the concentrator. 359 -{}- : bidirectional link 361 +-----+ +----------------+ 362 +-{}-| SAT |-{}-| BACKBONE | 363 +------+ +------+ | +-----+ | +------------+ | 364 | End |-{}-| CPE |-{}-| | |CONCENTRATOR| | 365 | User | | | | +-----+ | +------------+ | +------+ 366 +------+ +------+ |-{}-| DSL |-{}-| |-{}-|Data | 367 | +-----+ | | |Server| 368 | | | +------+ 369 | +-----+ | | 370 +-{}-| LTE |-{}-| | 371 +-----+ +----------------+ 373 Figure 5: Network architecture for an hybrid access using NC 375 4.4. Dealing with varying capacity 377 This use-case considers the usage of coding to cope with cases where 378 channel condition can change in less than a second and where the 379 physical layer codes could not guarantee a QEF transmission. 381 The architecture is recalled in Figure 6. In these cases, Adaptative 382 Coding and Modulation (ACM) may not adapt the modulation and coding 383 accordingly and remaining errors could be recovered with higher 384 layers redundancy packets. The coding schemes could be applied at 385 the access gateway or the network function block levels to increase 386 the reliability of the transmission. Coding may be applied on IP 387 packets or on layer-2 proprietary format packets. 389 This use-case is mostly relevant for when mobile users are considered 390 or when the chosen band induce a required physical layer coding that 391 may change over time (Q/V bands, Ka band, etc.). Depending on the 392 use-case (e.g. very high frequency bands, mobile users) or depending 393 on the deployment use-cases (e.g. performance of the network between 394 each individual block), the relevance of adding coding is different. 396 -{}- : bidirectional link 398 +---------+ +---+ +--------+ +-------+ +--------+ 399 |Satellite| |SAT| |Physical| |Access | |Network | 400 |Terminal |-{}-| |-{}-|Gateway |-{}-|Gateway|-{}-|Function| 401 +---------+ +---+ +--------+ +-------+ +--------+ 402 NC NC NC NC 404 Figure 6: Network architecture for dealing with varying link 405 characteristics with NC 407 4.5. Improving the gateway handovers 409 This use-case considers the recovery of packets that may be lost 410 during gateway handovers. Whether this is for off-loading one given 411 equipment or because the transmission quality is not the same on each 412 gateway, changing the transmission gateway may be relevant. However, 413 if gateways are not properly synchronized, this may result in packet 414 loss. During these critical phases, coding can be added to improve 415 the reliability of the transmission and allow a seamless gateway 416 handover. Coding could be applied at either the access gateway or 417 the network function block. The control plane manager is in charge 418 of taking the decision to change the communication gateway and the 419 consequent routes. 421 Figure 7 illustrates this use-case. Depending on the ground 422 architecture [I-D.chin-nfvrg-cloud-5g-core-structure-yang] [SAT2017], 423 some equipment might be communalised. 425 -{}- : bidirectional link 426 ! : management interface 427 NC NC 428 +--------+ +-------+ +--------+ 429 |Physical| |Access | |Network | 430 +-{}-|gateway |-{}-|gateway|-{}-|function| 431 | +--------+ +-------+ +--------+ 432 | ! ! 433 +---------+ +---+ +---------------+ 434 |Satellite| |SAT| | Control plane | 435 |Terminal |-{}-| | | manager | 436 +---------+ +---+ +---------------+ 437 | ! ! 438 | +--------+ +-------+ +--------+ 439 +-{}-|Physical|-{}-|Access |-{}-|Network | 440 |gateway | |gateway| |function| 441 +--------+ +-------+ +--------+ 442 NC NC 444 Figure 7: Network architecture for dealing with gateway handover 445 schemes with NC 447 5. Research challenges 449 5.1. Towards an increased deployability in SATCOM systems 451 SATCOM systems typically feature Performance Enhancement Proxy (PEP) 452 RFC 3135 [RFC3135]. PEP usually split TCP end-to-end connections and 453 forward TCP packets to the satellite baseband gateway that deals with 454 layer 2 and layer 1 encapsulations. PEP could host coding mechanisms 455 and thus support the use-cases that have been discussed in this 456 document. 458 Deploying coding schemes at the TCP level in these equipments could 459 be relevant and independent from the specificities of a SATCOM link. 460 However, there is a research issue in the recurrent trade-off in 461 SATCOM systems: how much reliability packets can be introduced to 462 guarantee a better end-user QoE while optimizing capacity usage ? 464 5.2. Interaction with virtualization 466 Related to the foreseen virtualized network infrastructure, coding 467 schemes could be easily deployed as Virtual Network Function (VNF). 468 Next generation of SATCOM ground segments could rely on a virtualized 469 environment. This trend can also be seen in cellular networks, 470 making these discussions extendable to other deployment scenarios 471 [I-D.chin-nfvrg-cloud-5g-core-structure-yang]. As one example, the 472 coding VNF functions deployment in a virtualized environment is 473 presented in [I-D.vazquez-nfvrg-netcod-function-virtualization]. 475 A research challenge would be the optimization of the NFV service 476 function chaining, considering a virtualized infrastructure and other 477 SATCOM specific functions, to guarantee an efficient radio usage and 478 easy-to-deploy SATCOM services. 480 5.3. Delay/Disruption Tolerant Networks 482 In the context of the deep-space communications, establishing 483 communications from terrestrial gateways to satellite platforms can 484 be a challenge. Reliable end-to-end (E2E) communications over such 485 links must cope with long delay and frequent link disruptions. 486 Delay/Disruption Tolerant Networking [RFC4838] is a solution to 487 enable reliable internetworking space communications where both 488 standard ad-hoc routing and E2E Internet protocols cannot be used. 489 Moreover, DTN can also be seen as an alternative solution to transfer 490 the data between a central PEP and a remote PEP. 492 Coding enables E2E reliable communication over DTN with adaptive re- 493 encoding, as proposed in [THAI15]. In this case, the use-cases 494 proposed in Section 4.4 would legitimate the usage of coding within 495 the DTN stack to improve the channel utilization and the E2E 496 transmission delay. In this context, the use of erasure coding 497 inside a Consultative Committee for Space Data Systems (CCSDS) 498 architecture has been specified in [CCSDS-131.5-O-1]. A research 499 challenge would be on how such coding can be integrated in the IETF 500 DTN stack. 502 6. Conclusion 504 This document presents the current deployment of coding in some 505 satellite telecommunications systems along with a discussion on the 506 multiple opportunities to introduce these techniques at a wider 507 scale. 509 Even if this document focuses on satellite systems, it is worth 510 pointing out that the some scenarios proposed may be relevant to 511 other wireless telecommunication systems. As one example, the 512 generic architecture proposed in Figure 1 may be mapped to cellular 513 networks as follows: the 'network function' block gather some of the 514 functions of the Evolved Packet Core subsystem, while the 'access 515 gateway' and 'physical gateway' blocks gather the same type of 516 functions as the Universal Mobile Terrestrial Radio Access Network. 517 This mapping extends the opportunities identified in this draft since 518 they may be also relevant for cellular networks. 520 7. Acknowledgements 522 Many thanks to Tomaso de Cola, Vincent Roca, Lloyd Wood and Marie- 523 Jose Montpetit for their help in writting this document. 525 8. IANA Considerations 527 This memo includes no request to IANA. 529 9. Security Considerations 531 Security considerations are inherent to any access network. SATCOM 532 systems introduce standard security mechanisms. In particular, there 533 are some specificities related to the fact that all users under the 534 coverage can record all the packets that are being transmitted, such 535 as in LTE networks. On the specific scenario of NC in SATCOM 536 systems, there are no specific security considerations. 538 10. References 540 10.1. Normative References 542 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 543 Requirement Levels", BCP 14, RFC 2119, 544 DOI 10.17487/RFC2119, March 1997, 545 . 547 10.2. Informative References 549 [ASMS2010] 550 De Cola, T. and et. al., "Demonstration at opening session 551 of ASMS 2010", ASMS , 2010. 553 [CCSDS-131.5-O-1] 554 CCSDS, "Erasure correcting codes for use in near-earth and 555 deep-space communications", CCSDS Experimental 556 specification 131.5-0-1, 2014. 558 [ETSITR2017] 559 "Satellite Earth Stations and Systems (SES); Multi-link 560 routing scheme in hybrid access network with heterogeneous 561 links", ETSI TR 103 351, 2017. 563 [I-D.chin-nfvrg-cloud-5g-core-structure-yang] 564 Chen, C. and Z. Pan, "Yang Data Model for Cloud Native 5G 565 Core structure", draft-chin-nfvrg-cloud-5g-core-structure- 566 yang-00 (work in progress), December 2017. 568 [I-D.ietf-tcpm-converters] 569 Bonaventure, O., Boucadair, M., Gundavelli, S., and S. 570 Seo, "0-RTT TCP Convert Protocol", draft-ietf-tcpm- 571 converters-04 (work in progress), October 2018. 573 [I-D.vazquez-nfvrg-netcod-function-virtualization] 574 Vazquez-Castro, M., Do-Duy, T., Romano, S., and A. Tulino, 575 "Network Coding Function Virtualization", draft-vazquez- 576 nfvrg-netcod-function-virtualization-02 (work in 577 progress), November 2017. 579 [RFC3135] Border, J., Kojo, M., Griner, J., Montenegro, G., and Z. 580 Shelby, "Performance Enhancing Proxies Intended to 581 Mitigate Link-Related Degradations", RFC 3135, 582 DOI 10.17487/RFC3135, June 2001, 583 . 585 [RFC4838] Cerf, V., Burleigh, S., Hooke, A., Torgerson, L., Durst, 586 R., Scott, K., Fall, K., and H. Weiss, "Delay-Tolerant 587 Networking Architecture", RFC 4838, DOI 10.17487/RFC4838, 588 April 2007, . 590 [RFC5326] Ramadas, M., Burleigh, S., and S. Farrell, "Licklider 591 Transmission Protocol - Specification", RFC 5326, 592 DOI 10.17487/RFC5326, September 2008, 593 . 595 [RFC5740] Adamson, B., Bormann, C., Handley, M., and J. Macker, 596 "NACK-Oriented Reliable Multicast (NORM) Transport 597 Protocol", RFC 5740, DOI 10.17487/RFC5740, November 2009, 598 . 600 [RFC6726] Paila, T., Walsh, R., Luby, M., Roca, V., and R. Lehtonen, 601 "FLUTE - File Delivery over Unidirectional Transport", 602 RFC 6726, DOI 10.17487/RFC6726, November 2012, 603 . 605 [RFC8406] Adamson, B., Adjih, C., Bilbao, J., Firoiu, V., Fitzek, 606 F., Ghanem, S., Lochin, E., Masucci, A., Montpetit, M-J., 607 Pedersen, M., Peralta, G., Roca, V., Ed., Saxena, P., and 608 S. Sivakumar, "Taxonomy of Coding Techniques for Efficient 609 Network Communications", RFC 8406, DOI 10.17487/RFC8406, 610 June 2018, . 612 [SAT2017] Ahmed, T., Dubois, E., Dupe, JB., Ferrus, R., Gelard, P., 613 and N. Kuhn, "Software-defined satellite cloud RAN", Int. 614 J. Satell. Commun. Network. vol. 36, 2017. 616 [SHINE] Pietro Romano, S. and et. al., "Secure Hybrid In Network 617 caching Environment (SHINE) ESA project", ESA project , 618 2017 on-going. 620 [THAI15] Thai, T., Chaganti, V., Lochin, E., Lacan, J., Dubois, E., 621 and P. Gelard, "Enabling E2E reliable communications with 622 adaptive re-encoding over delay tolerant networks", 623 Proceedings of the IEEE International Conference on 624 Communications , June 2015. 626 Authors' Addresses 628 Nicolas Kuhn (editor) 629 CNES 630 18 Avenue Edouard Belin 631 Toulouse 31400 632 France 634 Email: nicolas.kuhn@cnes.fr 635 Emmanuel Lochin (editor) 636 ISAE-SUPAERO 637 10 Avenue Edouard Belin 638 Toulouse 31400 639 France 641 Email: emmanuel.lochin@isae-supaero.fr