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Lochin, Ed. 5 Expires: August 31, 2020 ISAE-SUPAERO 6 February 28, 2020 8 Network coding for satellite systems 9 draft-irtf-nwcrg-network-coding-satellites-11 11 Abstract 13 This document is the product of the Coding for Efficient Network 14 Communications Research Group (NWCRG). It conforms to the directions 15 found in the NWCRG taxonomy [RFC8406]. Thus, the scope of the 16 document is network coding as a linear combination of packets in and 17 above the network layer. Physical and MAC layer coding are beyond 18 the scope of the document. The document focuses on a multi-gateway 19 satellite system and identifies the use-cases where network coding 20 provides significant performance improvements. The objective is to 21 contribute to a larger deployment of network coding techniques in and 22 above the network layer in satellite communication systems. These 23 systems generally exploit PHY layer loss recovery mechanisms. The 24 document also identifies open research issues related to the 25 deployment of network coding in satellite communication systems. 27 Status of This Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at https://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on August 31, 2020. 44 Copyright Notice 46 Copyright (c) 2020 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (https://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 62 2. A Note on Satellite Networks Topology . . . . . . . . . . . . 3 63 3. Use-cases for Improving SATCOM System Performance Using 64 Network Coding . . . . . . . . . . . . . . . . . . . . . . . 5 65 3.1. Two-way Relay Channel Mode . . . . . . . . . . . . . . . 5 66 3.2. Reliable Multicast . . . . . . . . . . . . . . . . . . . 5 67 3.3. Hybrid Access . . . . . . . . . . . . . . . . . . . . . . 6 68 3.4. LAN Packet Losses . . . . . . . . . . . . . . . . . . . . 7 69 3.5. Varying Channel Conditions . . . . . . . . . . . . . . . 8 70 3.6. Improving Gateway Handover . . . . . . . . . . . . . . . 8 71 4. Research Challenges . . . . . . . . . . . . . . . . . . . . . 9 72 4.1. Joint-use of Network Coding and Congestion Control in 73 SATCOM Systems . . . . . . . . . . . . . . . . . . . . . 9 74 4.2. Efficient Use of Satellite Resources . . . . . . . . . . 10 75 4.3. Interaction with Virtualized Satellite Gateways and 76 Terminals . . . . . . . . . . . . . . . . . . . . . . . . 10 77 4.4. Delay/Disruption Tolerant Networks . . . . . . . . . . . 10 78 5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 11 79 6. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 11 80 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 81 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 82 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13 83 10. Informative References . . . . . . . . . . . . . . . . . . . 13 84 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 86 1. Introduction 88 This document is the product of and represents the collaborative work 89 and consensus of the Coding for Efficient Network Communications 90 Research Group (NWCRG); while it is not an IETF product and not a 91 standard it intends to inform the SATCOM and Internet research 92 communities about recent developments in Network Coding. A glossary 93 is proposed in Section 6 to clarify the terminology use throughout 94 the document. 96 As will be shown in this document, the implementation of network 97 coding techniques above the network layer of the ISO model, at 98 application or transport layers, offers an opportunity for improving 99 the end-to-end performance of SATCOM systems. While physical- and 100 link-layer coding error protection is usually enough to provide 101 Quasi-Error Free transmission thus minimizing packet loss, when the 102 physical and link layers coding fail or that residual errors create 103 packet losses that greatly interfere with Internet protocols, 104 retransmissions add significant delays, in particular in 105 geostationary system with over 0.7 second round-trip delays. Hence 106 the use of network coding at the upper layers can improve the quality 107 of service in SATCOM subnetworks and eventually favorably impact the 108 experience of end users. 110 While there is an active research Community working on network coding 111 techniques above the network layer in general and in SATCOM in 112 particular, not much of this work made it to commercial systems in 113 the satellite industry. In this context, this document aims at 114 identifying opportunities for further usage of network coding in 115 commercial SATCOM networks. 117 The notation used in this document is based on the NWCRG taxonomy 118 [RFC8406]: 120 o Channel and link error correcting codes are considered part of the 121 PHY layer error protection and are out of the scope of this 122 document. 124 o FEC (also called Application-Level FEC) operates in and above the 125 network layer and targets packet loss recovery. 127 o This document considers only coding (or coding techniques or 128 coding schemes) that use a linear combination of packets and 129 excludes for example content coding (e.g., to compress a video 130 flow) or other non-linear operation. 132 2. A Note on Satellite Networks Topology 134 There are multiple SATCOM systems, for example broadcast TV, point to 135 point communication or IoT and monitoring. Therefore, depending on 136 the purpose of the system, the associated ground segments 137 architecture will be different. This section focuses on a satellite 138 system that follows the ETSI DVB standards to provide broadband 139 Internet access via ground-based gateways. One must note that the 140 overall data capacity of one satellite may be higher than the 141 capacity that one single gateway supports. Hence, there are usually 142 multiple gateways for one unique satellite platform. 144 In this context, Figure 1 shows an example of a multi-gateway 145 satellite system. More information on a generic SATCOM ground 146 segment architecture for bidirectional Internet access can be found 147 in [SAT2017]. 149 +--------------------------+ 150 | application servers | 151 | (data, coding, multicast)| 152 +--------------------------+ 153 | ... | 154 ----------------------------------- 155 | | | | | | 156 +--------------------+ +--------------------+ 157 | network function | | network function | 158 |(firewall, PEP, etc)| |(firewall, PEP, etc)| 159 +--------------------+ +--------------------+ 160 | ... | IP packets | ... | 161 --- 162 +------------------+ +------------------+ | 163 | access gateway | | access gateway | | 164 +------------------+ +------------------+ | 165 | BBFRAME | | gateway 166 +------------------+ +------------------+ | 167 | physical gateway | | physical gateway | | 168 +------------------+ +------------------+ | 169 --- 170 | PLFRAME | 171 +------------------+ +------------------+ 172 | outdoor unit | | outdoor unit | 173 +------------------+ +------------------+ 174 | satellite link | 175 +------------------+ +------------------+ 176 | outdoor unit | | outdoor unit | 177 +------------------+ +------------------+ 178 | | 179 +------------------+ +------------------+ 180 | sat terminals | | sat terminals | 181 +------------------+ +------------------+ 182 | | | | 183 +----------+ | +----------+ | 184 |end user 1| | |end user 3| | 185 +----------+ | +----------+ | 186 +----------+ +----------+ 187 |end user 2| |end user 4| 188 +----------+ +----------+ 190 Figure 1: Data plane functions in a generic satellite multi-gateway 191 system. More details can be found in DVB standard documents. 193 3. Use-cases for Improving SATCOM System Performance Using Network 194 Coding 196 This section details use-cases where network coding techniques could 197 improve SATCOM system performance. 199 3.1. Two-way Relay Channel Mode 201 This use-case considers two-way communication between end-users, 202 through a satellite link as seen in Figure 2. 204 Satellite terminal A sends a packet flow A and satellite terminal B 205 sends a packet flow B to a coding server. The coding server then 206 sends a combination of both flows instead of each individual flows. 207 This results in non-negligible capacity savings that has been 208 demonstrated in the past [ASMS2010]. In the example, a dedicated 209 coding server is introduced (note that its location could be 210 different based on deployment use-case). The network coding 211 operations could also be done at the satellite level, although this 212 would require a lot of computational resource on-board and may not be 213 supported by today's satellites. 215 -X}- : traffic from satellite terminal X to the server 216 ={X+Y= : traffic from X and Y combined sent from 217 the server to terminals X and Y 219 +-----------+ +-----+ 220 |Sat term A |--A}-+ | | 221 +-----------+ | | | +---------+ +------+ 222 ^^ +--| |--A}--| |--A}--|Coding| 223 || | SAT |--B}--| Gateway |--B}--|Server| 224 ===={A+B=========| |={A+B=| |={A+B=| | 225 || | | +---------+ +------+ 226 vv +--| | 227 +-----------+ | | | 228 |Sat term B |--B}-+ | | 229 +-----------+ +-----+ 231 Figure 2: Network Architecture for Two-way Relay Channel using NC 233 3.2. Reliable Multicast 235 The use of multicast servers is one way to better utilize satellite 236 broadcast capabilities. Multicast is proposed in the SHINE ESA 237 project [I-D.vazquez-nfvrg-netcod-function-virtualization] [SHINE]. 238 This use-case considers adding redundancy to a multicast flow 239 depending on what has been received by different end-users, resulting 240 in non-negligible savings of the scarce SATCOM resources. This 241 scenario is shown in Figure 3. 243 -Li}- : packet indicating the loss of packet i of a multicast flow M 244 ={M== : multicast flow including the missing packets 246 +-----------+ +-----+ 247 |Sat term A |-Li}-+ | | 248 +-----------+ | | | +---------+ +------+ 249 ^^ +-| |-Li}--| | |Multi | 250 || | SAT |-Lj}--| Gateway |--|Cast | 251 ===={M==========| |={M===| | |Server| 252 || | | +---------+ +------+ 253 vv +-| | 254 +-----------+ | | | 255 |Sat term B |-Lj}-+ | | 256 +-----------+ +-----+ 258 Figure 3: Network Architecture for a Reliable Multicast using NC 260 A multicast flow (M) is forwarded to both satellite terminals A and 261 B. However packet Ni (respectively Nj) gets lost at terminal A 262 (respectively B), and terminal A (respectively B) returns a negative 263 acknowledgment Li (respectively Lj), indicating that the packet is 264 missing. Using NC, either the access gateway or the multicast server 265 can include a repair packet (rather than the individual Ni and Nj 266 packets) in the multicast flow to let both terminals recover from 267 losses. 269 This could also be achieved by using other multicast or broadcast 270 systems, such as NACK-Oriented Reliable Multicast (NORM) [RFC5740] or 271 File Delivery over Unidirectional Transport (FLUTE) [RFC6726]. Both 272 NORM and FLUTE are limited to block coding, none of them supporting 273 more flexible sliding window encoding schemes that allow decoding 274 before receiving the whole block an added delay benefit 275 [RFC8406][RFC8681]. 277 3.3. Hybrid Access 279 This use-case considers improving multiple path communications with 280 network coding at the transport layer (see Figure 4). This use-case 281 is inspired by the Broadband Access via Integrated Terrestrial 282 Satellite Systems (BATS) project and has been published as an ETSI 283 Technical Report [ETSITR2017]. 285 To cope with packet loss (due to either end-user mobility or 286 physical-layer residual errors), network coding can be introduced 287 both at the CPE and at the concentrator. Apart from packet losses, 288 other gains from this approach include a better tolerance to out-of- 289 order packet delivery which occur when exploited links exhibit high 290 asymmetry in terms of RTT. Depending on the ground architecture 291 [I-D.chin-nfvrg-cloud-5g-core-structure-yang] [SAT2017], some ground 292 equipment might be hosting both SATCOM and cellular network 293 functionality. 295 -{}- : bidirectional link 297 +---+ +--------------+ 298 +-{}-|SAT|-{}-|BACKBONE | 299 +----+ +---+ | +---+ |+------------+| 300 |End |-{}-|CPE|-{}-| ||CONCENTRATOR|| 301 |User| +---+ | +---+ |+------------+| +-----------+ 302 +----+ |-{}-|DSL|-{}-| |-{}-|Application| 303 | +---+ | | |Server | 304 | | | +-----------+ 305 | +---+ | | 306 +-{}-|LTE|-{}-+--------------+ 307 +---+ 309 Figure 4: Network Architecture for a Hybrid Access Using Network 310 Coding 312 3.4. LAN Packet Losses 314 This use-case considers using network coding in the scenario where a 315 lossy WIFI link is used to connect to the SATCOM network. When 316 encrypted end-to-end applications based on UDP are used, a PEP cannot 317 operate hence other mechanism need to be used. The WIFI packet 318 losses will result in an end-to-end retransmission that will harm the 319 end-user quality of experience and poorly utilize SATCOM bottleneck 320 resource for non-revenue generating traffic. In this use-case, 321 adding network coding techniques will prevent the end-to-end 322 retransmission from occurring since the packet losses would probably 323 recovered. 325 The architecture is shown in Figure 5. 327 -{}- : bidirectional link 328 -''- : Wi-Fi link 329 C : where network coding techniques could be introduced 331 +----+ +--------+ +---+ +-------+ +-------+ +--------+ 332 |End | |Sat. | |SAT| |Phy | |Access | |Network | 333 |user|-''-|Terminal|-{}-| |-{}-|Gateway|-{}-|Gateway|-{}-|Function| 334 +----+ +--------+ +---+ +-------+ +-------+ +--------+ 335 C C C C 337 Figure 5: Network Architecture for dealing with LAN Losses 339 3.5. Varying Channel Conditions 341 This use-case considers the usage of network coding to cope with sub 342 second physical channel condition changes where the physical-layer 343 mechanisms (Adaptive Coding and Modulation (ACM)) may not adapt the 344 modulation and error-correction coding in time: the residual errors 345 lead to higher layer packet losses that can be recovered with network 346 coding. This use-case is mostly relevant when mobile users are 347 considered or when the satellite frequency band introduces quick 348 changes in channel condition (Q/V bands, Ka band, etc.). Depending 349 on the use-case (e.g., very high frequency bands, mobile users) or 350 depending on the deployment use-cases (e.g., performance of the 351 network between each individual data block), the relevance of adding 352 network coding is different. 354 The system architecture is shown in Figure 6. 356 -{}- : bidirectional link 357 C : where network coding techniques could be introduced 359 +---------+ +---+ +--------+ +-------+ +--------+ 360 |Satellite| |SAT| |Physical| |Access | |Network | 361 |Terminal |-{}-| |-{}-|Gateway |-{}-|Gateway|-{}-|Function| 362 +---------+ +---+ +--------+ +-------+ +--------+ 363 C C C C 365 Figure 6: Network Architecture for dealing with Varying Link 366 Characteristics 368 3.6. Improving Gateway Handover 370 This use-case considers the recovery of packets that may be lost 371 during gateway handover. Whether for off-loading a given equipment 372 or because the transmission quality differs from gateway to gateway, 373 switching the transmission gateway may be beneficial. However, 374 packet losses can occur if the gateways are not properly synchronized 375 or if the algorithm used to trigger gateway handover is not properly 376 tuned. During these critical phases, network coding can be added to 377 improve the reliability of the transmission and allow a seamless 378 gateway handover. 380 Figure 7 illustrates this use-case. 382 -{}- : bidirectional link 383 ! : management interface 384 C : where network coding techniques could be introduced 385 C C 386 +--------+ +-------+ +--------+ 387 |Physical| |Access | |Network | 388 +-{}-|gateway |-{}-|gateway|-{}-|function| 389 | +--------+ +-------+ +--------+ 390 | ! ! 391 +---------+ +---+ +---------------+ 392 |Satellite| |SAT| | Control plane | 393 |Terminal |-{}-| | | manager | 394 +---------+ +---+ +---------------+ 395 | ! ! 396 | +--------+ +-------+ +--------+ 397 +-{}-|Physical|-{}-|Access |-{}-|Network | 398 |gateway | |gateway| |function| 399 +--------+ +-------+ +--------+ 400 C C 402 Figure 7: Network Architecture for dealing with Gateway Handover 404 4. Research Challenges 406 This section proposes a few potential approaches to introduce and use 407 network coding in SATCOM systems. 409 4.1. Joint-use of Network Coding and Congestion Control in SATCOM 410 Systems 412 Many SATCOM systems typically use Performance Enhancing Proxy (PEP) 413 RFC 3135 [RFC3135]. PEPs usually split end-to-end connections and 414 forward transport or application layer packets to the satellite 415 baseband gateway that deals with layer-2 and layer-1 encapsulation. 416 PEPs contribute to mitigate congestion in a SATCOM systems by 417 limiting the impact of long delays on Internet protocols. A PEP 418 mechanism could also include network coding operation and thus 419 support the use-cases that have been discussed in the Section 3 of 420 this document. 422 Deploying network coding in the PEP could be relevant and be 423 independent from the specifics of a SATCOM link. This however leads 424 to research questions dealing with the potential interaction between 425 network coding and congestion control. This is discussed in 426 [I-D.irtf-nwcrg-coding-and-congestion] 428 4.2. Efficient Use of Satellite Resources 430 There is a recurrent trade-off in SATCOM systems: how much overhead 431 from redundant reliability packets can be introduced to guarantee a 432 better end-user QoE while optimizing capacity usage ? At which layer 433 this supplementary redundancy should be added ? 435 This problem has been tackled in the past by the deployment of 436 physical-layer error-correction codes, but there remains questions on 437 adapting the coding overhead and added delay for, e.g., the quickly 438 varying channel conditions use-case where ACM may not be reacting 439 quickly enough as was discussed in Section 3.5. 441 4.3. Interaction with Virtualized Satellite Gateways and Terminals 443 In the emerging virtualized network infrastructure, network coding 444 could be easily deployed as a Virtual Network Functions (VNF). The 445 next generation of SATCOM ground segments will rely on a virtualized 446 environment to integrate to terrestrial networks. This trend towards 447 Network Function Virtualization (NFV) is also central to 5G and next 448 generation cellular networks, making this research applicable to 449 other deployment scenarios 450 [I-D.chin-nfvrg-cloud-5g-core-structure-yang]. As one example, the 451 network coding VNF deployment in a virtualized environment has been 452 presented in [I-D.vazquez-nfvrg-netcod-function-virtualization]. 454 A research challenge would be the optimization of the NFV service 455 function chaining, considering a virtualized infrastructure and other 456 SATCOM specific functions, in order to guarantee efficient radio-link 457 usage and provide easy-to-deploy SATCOM services. Moreover, another 458 challenge related to a virtualized SATCOM equipment is the management 459 of limited buffered capacities in large gateways. 461 4.4. Delay/Disruption Tolerant Networks 463 Communications among deep-space platforms and terrestrial gateways 464 can be a challenge. Reliable end-to-end (E2E) communications over 465 such paths must cope with very long delays and frequent link 466 disruptions; indeed, E2E connectivity may be available only 467 intermittently. Delay/Disruption Tolerant Networking [RFC4838] is a 468 solution to enable reliable internetworking space communications 469 where both standard ad-hoc routing and E2E Internet protocols cannot 470 be used. Moreover, DTN can also be seen as an alternative solution 471 to transfer data between a central PEP and a remote PEP. 473 Network Coding enables E2E reliable communications over a DTN with 474 potential adaptive re-encoding, as proposed in [THAI15]. Here, the 475 use-cases proposed in Section 3.5 would legitimize the usage of 476 network coding within the DTN stack to improve the physical channel 477 utilization and minimize the effects of the E2E transmission delays. 478 In this context, the use of packet erasure coding techniques inside a 479 Consultative Committee for Space Data Systems (CCSDS) architecture 480 has been specified in [CCSDS-131.5-O-1]. One research challenge 481 remains on how such network coding can be integrated in the IETF DTN 482 stack. 484 5. Conclusion 486 This document introduces some wide-scale network coding techniques 487 opportunities in satellite telecommunications systems. 489 Even though this document focuses on satellite systems, it is worth 490 pointing out that some scenarios proposed here may be relevant to 491 other wireless telecommunication systems. As one example, the 492 generic architecture proposed in Figure 1 may be mapped onto cellular 493 networks as follows: the 'network function' block gathers some of the 494 functions of the Evolved Packet Core subsystem, while the 'access 495 gateway' and 'physical gateway' blocks gather the same type of 496 functions as the Universal Mobile Terrestrial Radio Access Network. 497 This mapping extends the opportunities identified in this document 498 since they may also be relevant for cellular networks. 500 6. Glossary 502 The glossary of this memo extends the glossary of the taxonomy 503 document [RFC8406] as follows: 505 o ACM : Adaptive Coding and Modulation; 507 o BBFRAME: Base-Band FRAME - satellite communication layer 2 508 encapsulation work as follows: (1) each layer 3 packet is 509 encapsulated with a Generic Stream Encapsulation (GSE) mechanism, 510 (2) GSE packets are gathered to create BBFRAMEs, (3) BBFRAMEs 511 contain information related to how they have to be modulated (4) 512 BBFRAMEs are forwarded to the physical-layer; 514 o CPE: Customer Premises Equipment; 516 o COM: COMmunication; 517 o DSL: Digital Subscriber Line; 519 o DTN: Delay/Disruption Tolerant Network; 521 o DVB: Digital Video Broadcasting; 523 o E2E: End-to-end; 525 o ETSI: European Telecommunications Standards Institute; 527 o FEC: Forward Erasure Correction; 529 o FLUTE: File Delivery over Unidirectional Transport; 531 o IntraF: Intra-Flow Coding; 533 o InterF: Inter-Flow Coding; 535 o IoT: Internet of Things; 537 o LTE: Long Term Evolution; 539 o MPC: Multi-Path Coding; 541 o NC: Network Coding; 543 o NFV: Network Function Virtualization - concept of running 544 software-defined network functions; 546 o NORM: NACK-Oriented Reliable Multicast; 548 o PEP: Performance Enhancing Proxy [RFC3135] - a typical PEP for 549 satellite communications include compression, caching and TCP 550 acceleration; 552 o PLFRAME: Physical Layer FRAME - modulated version of a BBFRAME 553 with additional information (e.g., related to synchronization); 555 o QEF: Quasi-Error-Free; 557 o QoE: Quality-of-Experience; 559 o QoS: Quality-of-Service; 561 o SAT: SATellite; 563 o SATCOM: generic term related to all kinds of SATellite 564 COMmunication systems; 566 o SPC: Single-Path Coding; 568 o VNF: Virtual Network Function - implementation of a network 569 function using software. 571 7. Acknowledgements 573 Many thanks to John Border, Stuart Card, Tomaso de Cola, Vincent 574 Roca, Lloyd Wood and Marie-Jose Montpetit for their help in writing 575 this document. 577 8. IANA Considerations 579 This memo includes no request to IANA. 581 9. Security Considerations 583 Security considerations are inherent to any access network, and in 584 particular SATCOM systems. The use of FEC or Network Coding in 585 SATCOM also comes with risks (e.g., a single corrupted redundant 586 packet may propagate to several flows when they are protected 587 together in an Inter-Flow coding approach, see section Section 3). 588 However, this is not specific to the SATCOM use-case and this 589 document does not further elaborate on it. 591 10. Informative References 593 [ASMS2010] 594 De Cola, T. and et. al., "Demonstration at opening session 595 of ASMS 2010", Advanced Satellite Multimedia Systems 596 (ASMS) Conference , 2010. 598 [CCSDS-131.5-O-1] 599 "Erasure correcting codes for use in near-earth and deep- 600 space communications", CCSDS Experimental 601 specification 131.5-0-1, 2014. 603 [ETSITR2017] 604 "Satellite Earth Stations and Systems (SES); Multi-link 605 routing scheme in hybrid access network with heterogeneous 606 links", ETSI TR 103 351, 2017. 608 [I-D.chin-nfvrg-cloud-5g-core-structure-yang] 609 Chen, C. and Z. Pan, "Yang Data Model for Cloud Native 5G 610 Core structure", draft-chin-nfvrg-cloud-5g-core-structure- 611 yang-00 (work in progress), December 2017. 613 [I-D.irtf-nwcrg-coding-and-congestion] 614 Kuhn, N., Lochin, E., Michel, F., and M. Welzl, "Coding 615 and congestion control in transport", draft-irtf-nwcrg- 616 coding-and-congestion-01 (work in progress), February 617 2020. 619 [I-D.vazquez-nfvrg-netcod-function-virtualization] 620 Vazquez-Castro, M., Do-Duy, T., Romano, S., and A. Tulino, 621 "Network Coding Function Virtualization", draft-vazquez- 622 nfvrg-netcod-function-virtualization-02 (work in 623 progress), November 2017. 625 [RFC3135] Border, J., Kojo, M., Griner, J., Montenegro, G., and Z. 626 Shelby, "Performance Enhancing Proxies Intended to 627 Mitigate Link-Related Degradations", RFC 3135, 628 DOI 10.17487/RFC3135, June 2001, 629 . 631 [RFC4838] Cerf, V., Burleigh, S., Hooke, A., Torgerson, L., Durst, 632 R., Scott, K., Fall, K., and H. Weiss, "Delay-Tolerant 633 Networking Architecture", RFC 4838, DOI 10.17487/RFC4838, 634 April 2007, . 636 [RFC5740] Adamson, B., Bormann, C., Handley, M., and J. Macker, 637 "NACK-Oriented Reliable Multicast (NORM) Transport 638 Protocol", RFC 5740, DOI 10.17487/RFC5740, November 2009, 639 . 641 [RFC6726] Paila, T., Walsh, R., Luby, M., Roca, V., and R. Lehtonen, 642 "FLUTE - File Delivery over Unidirectional Transport", 643 RFC 6726, DOI 10.17487/RFC6726, November 2012, 644 . 646 [RFC8406] Adamson, B., Adjih, C., Bilbao, J., Firoiu, V., Fitzek, 647 F., Ghanem, S., Lochin, E., Masucci, A., Montpetit, M-J., 648 Pedersen, M., Peralta, G., Roca, V., Ed., Saxena, P., and 649 S. Sivakumar, "Taxonomy of Coding Techniques for Efficient 650 Network Communications", RFC 8406, DOI 10.17487/RFC8406, 651 June 2018, . 653 [RFC8681] Roca, V. and B. Teibi, "Sliding Window Random Linear Code 654 (RLC) Forward Erasure Correction (FEC) Schemes for 655 FECFRAME", RFC 8681, DOI 10.17487/RFC8681, January 2020, 656 . 658 [SAT2017] Ahmed, T., Dubois, E., Dupe, JB., Ferrus, R., Gelard, P., 659 and N. Kuhn, "Software-defined satellite cloud RAN", 660 International Journal on Satellite Communnications and 661 Networking vol. 36 - https://doi.org/10.1002/sat.1206, 662 2017. 664 [SHINE] Pietro Romano, S. and et. al., "Secure Hybrid In Network 665 caching Environment (SHINE) ESA project", ESA project , 666 2017 on-going. 668 [THAI15] Thai, T., Chaganti, V., Lochin, E., Lacan, J., Dubois, E., 669 and P. Gelard, "Enabling E2E reliable communications with 670 adaptive re-encoding over delay tolerant networks", 671 Proceedings of the IEEE International Conference on 672 Communications http://dx.doi.org/10.1109/ICC.2015.7248441, 673 June 2015. 675 Authors' Addresses 677 Nicolas Kuhn (editor) 678 CNES 679 18 Avenue Edouard Belin 680 Toulouse 31400 681 France 683 Email: nicolas.kuhn@cnes.fr 685 Emmanuel Lochin (editor) 686 ISAE-SUPAERO 687 10 Avenue Edouard Belin 688 Toulouse 31400 689 France 691 Email: emmanuel.lochin@isae-supaero.fr