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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-12) exists of draft-irtf-nwcrg-coding-and-congestion-03 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NetWork Communications Research Group (NWCRG) N. Kuhn, Ed. 3 Internet-Draft CNES 4 Intended status: Informational E. Lochin, Ed. 5 Expires: May 3, 2021 ENAC 6 October 30, 2020 8 Network coding for satellite systems 9 draft-irtf-nwcrg-network-coding-satellites-15 11 Abstract 13 This document is one product of the Coding for Efficient Network 14 Communications Research Group (NWCRG). It conforms to the directions 15 found in the NWCRG taxonomy. 17 The objective is to contribute to a larger deployment of network 18 coding techniques in and above the network layer in satellite 19 communication systems. The document also identifies open research 20 issues related to the deployment of network coding in satellite 21 communication systems. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on May 3, 2021. 40 Copyright Notice 42 Copyright (c) 2020 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. A Note on Satellite Networks Topology . . . . . . . . . . . . 3 59 3. Use-cases for Improving SATCOM System Performance Using 60 Network Coding . . . . . . . . . . . . . . . . . . . . . . . 5 61 3.1. Two-way Relay Channel Mode . . . . . . . . . . . . . . . 5 62 3.2. Reliable Multicast . . . . . . . . . . . . . . . . . . . 5 63 3.3. Hybrid Access . . . . . . . . . . . . . . . . . . . . . . 6 64 3.4. LAN Packet Losses . . . . . . . . . . . . . . . . . . . . 7 65 3.5. Varying Channel Conditions . . . . . . . . . . . . . . . 8 66 3.6. Improving Gateway Handover . . . . . . . . . . . . . . . 8 67 4. Research Challenges . . . . . . . . . . . . . . . . . . . . . 9 68 4.1. Joint-use of Network Coding and Congestion Control in 69 SATCOM Systems . . . . . . . . . . . . . . . . . . . . . 9 70 4.2. Efficient Use of Satellite Resources . . . . . . . . . . 10 71 4.3. Interaction with Virtualized Satellite Gateways and 72 Terminals . . . . . . . . . . . . . . . . . . . . . . . . 10 73 4.4. Delay/Disruption Tolerant Networking (DTN) . . . . . . . 10 74 5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 11 75 6. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 11 76 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 77 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 78 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13 79 10. Informative References . . . . . . . . . . . . . . . . . . . 13 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 82 1. Introduction 84 This document is one product of and represents the collaborative work 85 and consensus of the Coding for Efficient Network Communications 86 Research Group (NWCRG); while it is not an IETF product and not a 87 standard it intends to inform the SATellite COMmunication (SATCOM) 88 and Internet research communities about recent developments in 89 Network Coding. A glossary is included in Section 6 to clarify the 90 terminology use throughout the document. 92 As will be shown in this document, the implementation of network 93 coding techniques above the network layer, at application or 94 transport layers (as described in [RFC1122]), offers an opportunity 95 for improving the end-to-end performance of SATCOM systems. While 96 physical- and link-layer coding error protection is usually enough to 97 provide Quasi-Error Free transmission thus minimizing packet loss, 98 when residual errors at those layers cause packet losses, 99 retransmissions add significant delays (in particular in 100 geostationary systems with over 0.7 second round-trip delays). Hence 101 the use of network coding at the upper layers can improve the quality 102 of service in SATCOM subnetworks and eventually favorably impact the 103 experience of end users. 105 While there is an active research community working on network coding 106 techniques above the network layer in general and in SATCOM in 107 particular, not much of this work has been deployed in commercial 108 systems. In this context, this document identifies opportunities for 109 further usage of network coding in commercial SATCOM networks. 111 The notation used in this document is based on the NWCRG taxonomy 112 [RFC8406]: 114 o Channel and link error correcting codes are considered part of the 115 PHYsical (PHY) layer error protection and are out of the scope of 116 this document. 118 o Forward Erasure Correction (FEC) (also called Application-Level 119 FEC) operates above the link layer and targets packet loss 120 recovery. 122 o This document considers only coding (or coding techniques or 123 coding schemes) that use a linear combination of packets and 124 excludes for example content coding (e.g., to compress a video 125 flow) or other non-linear operation. 127 2. A Note on Satellite Networks Topology 129 There are multiple SATCOM systems, for example broadcast TV, point to 130 point communication or IoT monitoring. Therefore, depending on the 131 purpose of the system, the associated ground segment architecture 132 will be different. This section focuses on a satellite system that 133 follows the European Telecommunications Standards Institute (ETSI) 134 Digital Video Broadcasting (DVB) standards to provide broadband 135 Internet access via ground-based gateways [ETSIEN2014]. One must 136 note that the overall data capacity of one satellite may be higher 137 than the capacity that one single gateway supports. Hence, there are 138 usually multiple gateways for one unique satellite platform. 140 In this context, Figure 1 shows an example of a multi-gateway 141 satellite system, where BBFRAME stands for Base-Band FRAME, PLFRAME 142 for Physical Layer FRAME and PEP for Performance Enhancing Proxy. 143 More information on a generic SATCOM ground segment architecture for 144 bidirectional Internet access can be found in [SAT2017]. 146 +--------------------------+ 147 | application servers | 148 | (data, coding, multicast)| 149 +--------------------------+ 150 | ... | 151 ----------------------------------- 152 | | | | | | 153 +--------------------+ +--------------------+ 154 | network function | | network function | 155 |(firewall, PEP, etc)| |(firewall, PEP, etc)| 156 +--------------------+ +--------------------+ 157 | ... | IP packets | ... | 158 --- 159 +------------------+ +------------------+ | 160 | access gateway | | access gateway | | 161 +------------------+ +------------------+ | 162 | BBFRAME | | gateway 163 +------------------+ +------------------+ | 164 | physical gateway | | physical gateway | | 165 +------------------+ +------------------+ | 166 --- 167 | PLFRAME | 168 +------------------+ +------------------+ 169 | outdoor unit | | outdoor unit | 170 +------------------+ +------------------+ 171 | satellite link | 172 +------------------+ +------------------+ 173 | outdoor unit | | outdoor unit | 174 +------------------+ +------------------+ 175 | | 176 +------------------+ +------------------+ 177 | sat terminals | | sat terminals | 178 +------------------+ +------------------+ 179 | | | | 180 +----------+ | +----------+ | 181 |end user 1| | |end user 3| | 182 +----------+ | +----------+ | 183 +----------+ +----------+ 184 |end user 2| |end user 4| 185 +----------+ +----------+ 187 Figure 1: Data plane functions in a generic satellite multi-gateway 188 system. More details can be found in DVB standard documents. 190 3. Use-cases for Improving SATCOM System Performance Using Network 191 Coding 193 This section details use-cases where network coding techniques could 194 improve SATCOM system performance. 196 3.1. Two-way Relay Channel Mode 198 This use-case considers two-way communication between end-users, 199 through a satellite link as seen in Figure 2. 201 Satellite terminal A sends a packet flow A and satellite terminal B 202 sends a packet flow B to a coding server. The coding server then 203 sends a combination of both flows instead of each individual flows. 204 This results in non-negligible capacity savings that has been 205 demonstrated in the past [ASMS2010]. In the example, a dedicated 206 coding server is introduced (note that its location could be 207 different based on deployment use-case). The network coding 208 operations could also be done at the satellite level, although this 209 would require a lot of computational resources on-board and may not 210 be supported by today's satellites. 212 -X}- : traffic from satellite terminal X to the server 213 ={X+Y= : traffic from X and Y combined sent from 214 the server to terminals X and Y 216 +-----------+ +-----+ 217 |Sat term A |--A}-+ | | 218 +-----------+ | | | +---------+ +------+ 219 ^^ +--| |--A}--| |--A}--|Coding| 220 || | SAT |--B}--| Gateway |--B}--|Server| 221 ===={A+B=========| |={A+B=| |={A+B=| | 222 || | | +---------+ +------+ 223 vv +--| | 224 +-----------+ | | | 225 |Sat term B |--B}-+ | | 226 +-----------+ +-----+ 228 Figure 2: Network Architecture for Two-way Relay Channel using NC 230 3.2. Reliable Multicast 232 The use of multicast servers is one way to better utilize satellite 233 broadcast capabilities. As one example satellite-based multicast is 234 proposed in the SHINE ESA project 235 [I-D.vazquez-nfvrg-netcod-function-virtualization] [SHINE]. This 236 use-case considers adding redundancy to a multicast flow depending on 237 what has been received by different end-users, resulting in non- 238 negligible savings of the scarce SATCOM resources. This scenario is 239 shown in Figure 3. 241 -Li}- : packet indicating the loss of packet i of a multicast flow M 242 ={M== : multicast flow including the missing packets 244 +-----------+ +-----+ 245 |Terminal A |-Li}-+ | | 246 +-----------+ | | | +---------+ +------+ 247 ^^ +-| |-Li}--| | |Multi | 248 || | SAT |-Lj}--| Gateway |--|Cast | 249 ===={M==========| |={M===| | |Server| 250 || | | +---------+ +------+ 251 vv +-| | 252 +-----------+ | | | 253 |Terminal B |-Lj}-+ | | 254 +-----------+ +-----+ 256 Figure 3: Network Architecture for a Reliable Multicast using NC 258 A multicast flow (M) is forwarded to both satellite terminals A and 259 B. However packet Ni (respectively Nj) gets lost at terminal A 260 (respectively B), and terminal A (respectively B) returns a negative 261 acknowledgment Li (respectively Lj), indicating that the packet is 262 missing. Using coding, either the access gateway or the multicast 263 server can include a repair packet (rather than the individual Ni and 264 Nj packets) in the multicast flow to let both terminals recover from 265 losses. 267 This could also be achieved by using other multicast or broadcast 268 systems, such as NACK-Oriented Reliable Multicast (NORM) [RFC5740] or 269 File Delivery over Unidirectional Transport (FLUTE) [RFC6726]. Both 270 NORM and FLUTE are limited to block coding; neither of them support 271 more flexible sliding window encoding schemes that allow decoding 272 before receiving the whole block an added delay benefit 273 [RFC8406][RFC8681]. 275 3.3. Hybrid Access 277 This use-case considers improving multiple path communications with 278 network coding at the transport layer (see Figure 4, where DSL stands 279 for Digital Subscriber Line, LTE for Long Term Evolution and SAT for 280 SATellite). This use-case is inspired by the Broadband Access via 281 Integrated Terrestrial Satellite Systems (BATS) project and has been 282 published as an ETSI Technical Report [ETSITR2017]. 284 To cope with packet loss (due to either end-user mobility or 285 physical-layer residual errors), network coding can be introduced. 287 Depending on the protocol, network coding could be applied at each of 288 the Customer Premises Equipment (CPE) and at the concentrator or 289 both. Apart from packet losses, other gains from this approach 290 include a better tolerance to out-of-order packet delivery which 291 occur when exploited links exhibit high asymmetry in terms of Round- 292 Trip Time (RTT). Depending on the ground architecture 293 [I-D.chin-nfvrg-cloud-5g-core-structure-yang] [SAT2017], some ground 294 equipment might be hosting both SATCOM and cellular network 295 functionality. 297 -{}- : bidirectional link 299 +---+ +--------------+ 300 +-{}-|SAT|-{}-|BACKBONE | 301 +----+ +---+ | +---+ |+------------+| 302 |End |-{}-|CPE|-{}-| ||CONCENTRATOR|| 303 |User| +---+ | +---+ |+------------+| +-----------+ 304 +----+ |-{}-|DSL|-{}-| |-{}-|Application| 305 | +---+ | | |Server | 306 | | | +-----------+ 307 | +---+ | | 308 +-{}-|LTE|-{}-+--------------+ 309 +---+ 311 Figure 4: Network Architecture for a Hybrid Access Using Network 312 Coding 314 3.4. LAN Packet Losses 316 This use-case considers using network coding in the scenario where a 317 lossy WIFI link is used to connect to the SATCOM network. When 318 encrypted end-to-end applications based on UDP are used, a 319 Performance Enhancing Proxy (PEP) cannot operate hence other 320 mechanism need to be used. The WIFI packet losses will result in an 321 end-to-end retransmission that will harm the end-user quality of 322 experience and poorly utilize SATCOM bottleneck resource for non- 323 revenue generating traffic. In this use-case, adding network coding 324 techniques will prevent the end-to-end retransmission from occurring 325 since the packet losses would probably be recovered. 327 The architecture is shown in Figure 5. 329 -{}- : bidirectional link 330 -''- : Wi-Fi link 331 C : where network coding techniques could be introduced 333 +----+ +--------+ +---+ +-------+ +-------+ +--------+ 334 |End | |Sat. | |SAT| |Phy | |Access | |Network | 335 |user|-''-|Terminal|-{}-| |-{}-|Gateway|-{}-|Gateway|-{}-|Function| 336 +----+ +--------+ +---+ +-------+ +-------+ +--------+ 337 C C C C 339 Figure 5: Network Architecture for dealing with LAN Losses 341 3.5. Varying Channel Conditions 343 This use-case considers the usage of network coding to cope with sub 344 second physical channel condition changes where the physical-layer 345 mechanisms (Adaptive Coding and Modulation (ACM)) may not adapt the 346 modulation and error-correction coding in time: the residual errors 347 lead to higher layer packet losses that can be recovered with network 348 coding. This use-case is mostly relevant when mobile users are 349 considered or when the satellite frequency band introduces quick 350 changes in channel condition (Q/V bands, Ka band, etc.). Depending 351 on the use-case (e.g., very high frequency bands, mobile users), the 352 relevance of adding 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. PEPs contribute to mitigate congestion in a SATCOM 416 systems by limiting the impact of long delays on Internet protocols. 417 A PEP mechanism could also include network coding operation and thus 418 support the use-cases that have been discussed in the Section 3 of 419 this document. 421 Deploying network coding in the PEP could be relevant and be 422 independent from the specifics of a SATCOM link. This however leads 423 to research questions dealing with the potential interaction between 424 network coding and congestion control. This is discussed in 425 [I-D.irtf-nwcrg-coding-and-congestion]. 427 4.2. Efficient Use of Satellite Resources 429 There is a recurrent trade-off in SATCOM systems: how much overhead 430 from redundant reliability packets can be introduced to guarantee a 431 better end-user QoE while optimizing capacity usage? At which layer 432 this supplementary redundancy should be added? 434 This problem has been tackled in the past by the deployment of 435 physical-layer error-correction codes, but there remains questions on 436 adapting the coding overhead and added delay for, e.g., the quickly 437 varying channel conditions use-case where ACM may not be reacting 438 quickly enough as was discussed in Section 3.5. The higher layer 439 with network coding does not react more quickly than the physical 440 layer, but may operate over a packet-based time window that is larger 441 than the physical one. 443 4.3. Interaction with Virtualized Satellite Gateways and Terminals 445 In the emerging virtualized network infrastructure, network coding 446 could be easily deployed as Virtual Network Functions (VNF). The 447 next generation of SATCOM ground segments will rely on a virtualized 448 environment to integrate to terrestrial networks. This trend towards 449 Network Function Virtualization (NFV) is also central to 5G and next 450 generation cellular networks, making this research applicable to 451 other deployment scenarios 452 [I-D.chin-nfvrg-cloud-5g-core-structure-yang]. As one example, the 453 network coding VNF deployment in a virtualized environment has been 454 presented in [I-D.vazquez-nfvrg-netcod-function-virtualization]. 456 A research challenge would be the optimization of the NFV service 457 function chaining, considering a virtualized infrastructure and other 458 SATCOM specific functions, in order to guarantee efficient radio-link 459 usage and provide easy-to-deploy SATCOM services. Moreover, another 460 challenge related to a virtualized SATCOM equipment is the management 461 of limited buffered capacities in large gateways. 463 4.4. Delay/Disruption Tolerant Networking (DTN) 465 Communications among deep-space platforms and terrestrial gateways 466 can be a challenge. Reliable end-to-end (E2E) communications over 467 such paths must cope with very long delays and frequent link 468 disruptions; indeed, E2E connectivity may only be available 469 intermittently, if at all. Delay/Disruption Tolerant Networking 470 (DTN) [RFC4838] is a solution to enable reliable internetworking 471 space communications where both standard ad-hoc routing and E2E 472 Internet protocols cannot be used. Moreover, DTN can also be seen as 473 an alternative solution to transfer data between a central PEP and a 474 remote PEP. 476 Network Coding enables E2E reliable communications over a DTN with 477 potential adaptive re-encoding, as proposed in [THAI15]. Here, the 478 use-cases proposed in Section 3.5 would encourage the usage of 479 network coding within the DTN stack to improve the physical channel 480 utilization and minimize the effects of the E2E transmission delays. 481 In this context, the use of packet erasure coding techniques inside a 482 Consultative Committee for Space Data Systems (CCSDS) architecture 483 has been specified in [CCSDS-131.5-O-1]. One research challenge 484 remains on how such network coding can be integrated in the IETF DTN 485 stack. 487 5. Conclusion 489 This document introduces some wide-scale network coding technique 490 opportunities in satellite telecommunications systems. 492 Even though this document focuses on satellite systems, it is worth 493 pointing out that some scenarios proposed here may be relevant to 494 other wireless telecommunication systems. As one example, the 495 generic architecture proposed in Figure 1 may be mapped onto cellular 496 networks as follows: the 'network function' block gathers some of the 497 functions of the Evolved Packet Core subsystem, while the 'access 498 gateway' and 'physical gateway' blocks gather the same type of 499 functions as the Universal Mobile Terrestrial Radio Access Network. 500 This mapping extends the opportunities identified in this document 501 since they may also be relevant for cellular networks. 503 6. Glossary 505 The glossary of this memo extends the glossary of the taxonomy 506 document [RFC8406] as follows: 508 o ACM : Adaptive Coding and Modulation; 510 o BBFRAME: Base-Band FRAME - satellite communication layer 2 511 encapsulation work as follows: (1) each layer 3 packet is 512 encapsulated with a Generic Stream Encapsulation (GSE) mechanism, 513 (2) GSE packets are gathered to create BBFRAMEs, (3) BBFRAMEs 514 contain information related to how they have to be modulated (4) 515 BBFRAMEs are forwarded to the physical-layer; 517 o CPE: Customer Premises Equipment; 519 o COM: COMmunication; 520 o DSL: Digital Subscriber Line; 522 o DTN: Delay/Disruption Tolerant Networking; 524 o DVB: Digital Video Broadcasting; 526 o E2E: End-to-end; 528 o ETSI: European Telecommunications Standards Institute; 530 o FEC: Forward Erasure Correction; 532 o FLUTE: File Delivery over Unidirectional Transport [RFC6726]; 534 o IntraF: Intra-Flow Coding; 536 o InterF: Inter-Flow Coding; 538 o IoT: Internet of Things; 540 o LTE: Long Term Evolution; 542 o MPC: Multi-Path Coding; 544 o NC: Network Coding; 546 o NFV: Network Function Virtualization - concept of running 547 software-defined network functions; 549 o NORM: NACK-Oriented Reliable Multicast [RFC5740]; 551 o PEP: Performance Enhancing Proxy [RFC3135] - a typical PEP for 552 satellite communications include compression, caching and TCP ACK 553 spoofing and specific congestion control tuning; 555 o PLFRAME: Physical Layer FRAME - modulated version of a BBFRAME 556 with additional information (e.g., related to synchronization); 558 o QEF: Quasi-Error-Free; 560 o QoE: Quality-of-Experience; 562 o QoS: Quality-of-Service; 564 o RTT: Round-Trip Time; 566 o SAT: SATellite; 567 o SATCOM: generic term related to all kinds of SATellite 568 COMmunication systems; 570 o SPC: Single-Path Coding; 572 o VNF: Virtual Network Function - implementation of a network 573 function using software. 575 7. Acknowledgements 577 Many thanks to John Border, Stuart Card, Tomaso de Cola, Vincent 578 Roca, Lloyd Wood and Marie-Jose Montpetit for their help in writing 579 this document. 581 8. IANA Considerations 583 This memo includes no request to IANA. 585 9. Security Considerations 587 Security considerations are inherent to any access network, and in 588 particular SATCOM systems. Such as it is done in cellular networks, 589 over-the-air data can be encrypted using e.g. [ETSITS2011]. Because 590 the operator may not enable this [SSP-2020], the applications should 591 apply cryptographic protection. The use of FEC or Network Coding in 592 SATCOM comes with risks (e.g., a single corrupted redundant packet 593 may propagate to several flows when they are protected together in an 594 Inter-Flow coding approach, see section Section 3). While this 595 document does not further elaborate on this, the security 596 considerations discussed in [RFC6363] apply. 598 10. Informative References 600 [ASMS2010] 601 De Cola, T. and et. al., "Demonstration at opening session 602 of ASMS 2010", Advanced Satellite Multimedia Systems 603 (ASMS) Conference , 2010. 605 [CCSDS-131.5-O-1] 606 "Erasure correcting codes for use in near-earth and deep- 607 space communications", CCSDS Experimental 608 specification 131.5-0-1, 2014. 610 [ETSIEN2014] 611 "Digital Video Broadcasting (DVB); Second Generation DVB 612 Interactive Satellite System (DVB-RCS2); Part 2: Lower 613 Layers for Satellite standard", ETSI EN 301 545-2, 2014. 615 [ETSITR2017] 616 "Satellite Earth Stations and Systems (SES); Multi-link 617 routing scheme in hybrid access network with heterogeneous 618 links", ETSI TR 103 351, 2017. 620 [ETSITS2011] 621 "Digital Video Broadcasting (DVB);Content Protection and 622 Copy Management (DVB-CPCM);Part 5: CPCM Security Toolbox", 623 ETSI TS 102 825-5, 2011. 625 [I-D.chin-nfvrg-cloud-5g-core-structure-yang] 626 Chen, C. and Z. Pan, "Yang Data Model for Cloud Native 5G 627 Core structure", draft-chin-nfvrg-cloud-5g-core-structure- 628 yang-00 (work in progress), December 2017. 630 [I-D.irtf-nwcrg-coding-and-congestion] 631 Kuhn, N., Lochin, E., Michel, F., and M. Welzl, "Coding 632 and congestion control in transport", draft-irtf-nwcrg- 633 coding-and-congestion-03 (work in progress), July 2020. 635 [I-D.vazquez-nfvrg-netcod-function-virtualization] 636 Vazquez-Castro, M., Do-Duy, T., Romano, S., and A. Tulino, 637 "Network Coding Function Virtualization", draft-vazquez- 638 nfvrg-netcod-function-virtualization-02 (work in 639 progress), November 2017. 641 [RFC1122] Braden, R., Ed., "Requirements for Internet Hosts - 642 Communication Layers", STD 3, RFC 1122, 643 DOI 10.17487/RFC1122, October 1989, 644 . 646 [RFC3135] Border, J., Kojo, M., Griner, J., Montenegro, G., and Z. 647 Shelby, "Performance Enhancing Proxies Intended to 648 Mitigate Link-Related Degradations", RFC 3135, 649 DOI 10.17487/RFC3135, June 2001, 650 . 652 [RFC4838] Cerf, V., Burleigh, S., Hooke, A., Torgerson, L., Durst, 653 R., Scott, K., Fall, K., and H. Weiss, "Delay-Tolerant 654 Networking Architecture", RFC 4838, DOI 10.17487/RFC4838, 655 April 2007, . 657 [RFC5740] Adamson, B., Bormann, C., Handley, M., and J. Macker, 658 "NACK-Oriented Reliable Multicast (NORM) Transport 659 Protocol", RFC 5740, DOI 10.17487/RFC5740, November 2009, 660 . 662 [RFC6363] Watson, M., Begen, A., and V. Roca, "Forward Error 663 Correction (FEC) Framework", RFC 6363, 664 DOI 10.17487/RFC6363, October 2011, 665 . 667 [RFC6726] Paila, T., Walsh, R., Luby, M., Roca, V., and R. Lehtonen, 668 "FLUTE - File Delivery over Unidirectional Transport", 669 RFC 6726, DOI 10.17487/RFC6726, November 2012, 670 . 672 [RFC8406] Adamson, B., Adjih, C., Bilbao, J., Firoiu, V., Fitzek, 673 F., Ghanem, S., Lochin, E., Masucci, A., Montpetit, M-J., 674 Pedersen, M., Peralta, G., Roca, V., Ed., Saxena, P., and 675 S. Sivakumar, "Taxonomy of Coding Techniques for Efficient 676 Network Communications", RFC 8406, DOI 10.17487/RFC8406, 677 June 2018, . 679 [RFC8681] Roca, V. and B. Teibi, "Sliding Window Random Linear Code 680 (RLC) Forward Erasure Correction (FEC) Schemes for 681 FECFRAME", RFC 8681, DOI 10.17487/RFC8681, January 2020, 682 . 684 [SAT2017] Ahmed, T., Dubois, E., Dupe, JB., Ferrus, R., Gelard, P., 685 and N. Kuhn, "Software-defined satellite cloud RAN", 686 International Journal on Satellite Communnications and 687 Networking vol. 36 - https://doi.org/10.1002/sat.1206, 688 2017. 690 [SHINE] Pietro Romano, S. and et. al., "Secure Hybrid In Network 691 caching Environment (SHINE) ESA project", ESA project , 692 2017 on-going. 694 [SSP-2020] 695 Pavur (et al.), J., "A Tale of Sea and SkyOn the Security 696 of Maritime VSAT Communications", IEEE Symposium on 697 Security and Privacy 10.1109/SP40000.2020.00056, 2020. 699 [THAI15] Thai, T., Chaganti, V., Lochin, E., Lacan, J., Dubois, E., 700 and P. Gelard, "Enabling E2E reliable communications with 701 adaptive re-encoding over delay tolerant networks", 702 Proceedings of the IEEE International Conference on 703 Communications http://dx.doi.org/10.1109/ICC.2015.7248441, 704 June 2015. 706 Authors' Addresses 708 Nicolas Kuhn (editor) 709 CNES 710 18 avenue Edouard Belin 711 Toulouse 31400 712 France 714 Email: nicolas.kuhn@cnes.fr 716 Emmanuel Lochin (editor) 717 ENAC 718 7 avenue Edouard Belin 719 Toulouse 31400 720 France 722 Email: emmanuel.lochin@enac.fr