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Versions: (draft-kuhn-nwcrg-network-coding-satellites) 00 01 02 03 04 05 06 07 08

Internet Engineering Task Force                             N. Kuhn, Ed.
Internet-Draft                                                      CNES
Intended status: Informational                            E. Lochin, Ed.
Expires: May 21, 2020                                       ISAE-SUPAERO
                                                       November 18, 2019


                  Network coding for satellite systems
             draft-irtf-nwcrg-network-coding-satellites-08

Abstract

   This document is the product of the Coding for Efficient Network
   Communications Research Group (NWCRG).  This document follows the
   taxonomy document [RFC8406] and considers coding as a linear
   combination of packets that operate in and above the network layer.
   In this context, this memo details a multi-gateway satellite system
   to identify use-cases where network coding is relevant.  As example,
   network coding operating in and above the network layer can be
   exploited to cope with residual losses or provide reliable multicast
   services.  The objective is to contribute to a larger deployment of
   such techniques in SATCOM systems.  This memo also identifies open
   research issues related to the deployment of network coding in SATCOM
   systems, such as the interaction between congestion control and
   network coding techniques.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 21, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  A note on satellite topology  . . . . . . . . . . . . . . . .   3
   3.  Use-cases for improving the SATCOM system performance with
       network coding  . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Two-way relay channel mode  . . . . . . . . . . . . . . .   5
     3.2.  Reliable multicast  . . . . . . . . . . . . . . . . . . .   5
     3.3.  Hybrid access . . . . . . . . . . . . . . . . . . . . . .   6
     3.4.  Dealing with LAN losses . . . . . . . . . . . . . . . . .   7
     3.5.  Dealing with varying channel conditions . . . . . . . . .   8
     3.6.  Improving the gateway handovers . . . . . . . . . . . . .   8
   4.  Research challenges . . . . . . . . . . . . . . . . . . . . .   9
     4.1.  On the joint-use of network coding and congestion control
           in SATCOM systems . . . . . . . . . . . . . . . . . . . .   9
     4.2.  On the efficient usage of satellite resource  . . . . . .  10
     4.3.  Interaction with virtualized satellite gateways and
           terminals . . . . . . . . . . . . . . . . . . . . . . . .  10
     4.4.  Delay/Disruption Tolerant Networks  . . . . . . . . . . .  10
   5.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .  11
   6.  Glossary  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   10. Informative References  . . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   This document is the product of and represents the collaborative work
   and consensus of the Coding for Efficient Network Communications
   Research Group (NWCRG); it is not an IETF product and is not a
   standard.  A glossary is proposed in Section 6.

   Exploiting network coding techniques at application or transport
   layers is an opportunity for improving the end-to-end performance of
   SATCOM systems.  Physical and link layers coding protection is
   usually sufficient to guarranty Quasi-Error Free, with a negligeable



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   delay compared to the propagation time (e.g., with a GEO sat).  When
   the physical and link layers coding fails, retransmissions add
   significant delays.  Hence the use of network coding in upper layers
   can improve the quality of experience of end users.

   We notice an active research activity on network coding techniques
   above the network layer and SATCOM.  That being said, not much has
   actually made it to industrial developments.  In this context, this
   document aims at identifying opportunities for further usage of
   network coding in these systems.

   The notations used in this document are based on the taxonomy
   document [RFC8406]:

   o  Channel and link codings are gathered in the PHY layer coding and
      are out of the scope of this document.

   o  FEC (also called Application-Level FEC) operates in and above the
      network layer.

   o  This document considers coding (or coding techniques or coding
      schemes) as a linear combination and not as a content coding
      (e.g., to compress a video flow).

2.  A note on satellite topology

   There are multiple SATCOM systems, such as those dedicated to
   broadcasting TV or to IoT applications: depending on the purpose of
   the SATCOM system, the ground segments are different.  This section
   focuses on a satellite system that follows the ETSI DVB standards to
   provide broadband Internet access.  The capacity that is carried out
   by one satellite may be higher than the capacity that one single
   gateway can carry out: there are usually multiple gateways for one
   unique satellite platform.

   In this context, Figure 1 shows an example of a multi-gateway
   satellite system.  More information on a generic SATCOM ground
   segment architecture for bidirectional Internet access can be found
   in [SAT2017].












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   +--------------------------+
   | application servers      |
   | (data, coding, multicast)|
   +--------------------------+
          | ... |
          -----------------------------------
          |     |   |             |   |     |
   +--------------------+     +--------------------+
   | network function   |     | network function   |
   |(firewall, PEP, etc)|     |(firewall, PEP, etc)|
   +--------------------+     +--------------------+
       | ... | IP packets             |  ...   |
                                                   ---
   +------------------+         +------------------+ |
   | access gateway   |         | access gateway   | |
   +------------------+         +------------------+ |
          | BBFRAME                         |        | gateway
   +------------------+         +------------------+ |
   | physical gateway |         | physical gateway | |
   +------------------+         +------------------+ |
                                                   ---
          | PLFRAME                         |
   +------------------+         +------------------+
   | outdoor unit     |         | outdoor unit     |
   +------------------+         +------------------+
          | satellite link                  |
   +------------------+         +------------------+
   | outdoor unit     |         | outdoor unit     |
   +------------------+         +------------------+
          |                                 |
   +------------------+         +------------------+
   | sat terminals    |         | sat terminals    |
   +------------------+         +------------------+
          |        |                  |        |
   +----------+    |            +----------+   |
   |end user 1|    |            |end user 3|   |
   +----------+    |            +----------+   |
             +----------+               +----------+
             |end user 2|               |end user 4|
             +----------+               +----------+

    Figure 1: Data plane functions in a generic satellite multi-gateway
       system.  More details can be found in DVB standard documents.








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3.  Use-cases for improving the SATCOM system performance with network
    coding

   This section details use-cases where network coding techniques could
   improve SATCOM systems.

3.1.  Two-way relay channel mode

   This use-case considers a two-way communication between end users,
   through a satellite link.  Figure 2 proposes an illustration of this
   scenario.

   Satellite terminal A sends a flow A and satellite terminal B sends a
   flow B to a coding server.  The coding server sends a combination of
   both terminal flows.  This results in non-negligible capacity savings
   and has been demonstrated [ASMS2010].  In the proposed example, a
   dedicated coding server is introduced (note that its location could
   be different for another deployment use-case).  The network coding
   operations could also be done at the satellite level, although this
   would require lots of computational ressource on-board and may not be
   relevant with today's satellites.

   -X}-   : traffic from satellite terminal X to the server
   ={X+Y= : traffic from X and Y combined sent from
               the server to terminals X and Y

   +-----------+        +-----+
   |Sat term A |--A}-+  |     |
   +-----------+     |  |     |      +---------+      +------+
       ^^            +--|     |--A}--|         |--A}--|Coding|
       ||               | SAT |--B}--| Gateway |--B}--|Server|
       ===={A+B=========|     |={A+B=|         |={A+B=|      |
       ||               |     |      +---------+      +------+
       vv            +--|     |
   +-----------+     |  |     |
   |Sat term B |--B}-+  |     |
   +-----------+        +-----+

     Figure 2: Network architecture for two way relay channel with NC

3.2.  Reliable multicast

   Using multicast servers is a way to better exploit the satellite
   broadcast capabilities.  This approach is proposed in the SHINE ESA
   project [I-D.vazquez-nfvrg-netcod-function-virtualization] [SHINE].
   This use-case considers adding redundancy to a multicast flow
   depending on what has been received by different end-users, resulting




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   in non-negligible scarce resource saving.  We propose an illustration
   for this scenario in Figure 3.

   -Li}- : packet indicating the loss of packet i of a multicast flow M
   ={M== : multicast flow including the missing packets

   +-----------+       +-----+
   |Sat term A |-Li}-+ |     |
   +-----------+     | |     |      +---------+  +------+
       ^^            +-|     |-Li}--|         |  |Multi |
       ||              | SAT |-Lj}--| Gateway |--|Cast  |
       ===={M==========|     |={M===|         |  |Server|
       ||              |     |      +---------+  +------+
       vv            +-|     |
   +-----------+     | |     |
   |Sat term B |-Lj}-+ |     |
   +-----------+       +-----+

      Figure 3: Network architecture for a reliable multicast with NC

   A multicast flow (M) is forwarded to both satellite terminals A and
   B.  However packet Ni (resp.  Nj) gets lost at terminal A (resp.  B),
   and terminal A (resp.  B) returns a negative acknowledgment Li (resp.
   Lj), indicating that the packet is missing.  Then either the access
   gateway or the multicast server includes a repair packet (rather than
   the individual Ni and Nj packets) in the multicast flow to let both
   terminals recover from losses.

   This could be achieved by using other multicast or broadcast systems,
   such as NACK-Oriented Reliable Multicast (NORM) [RFC5740] or File
   Delivery over Unidirectional Transport (FLUTE) [RFC6726].  Note that
   both NORM and FLUTE are limited to block coding, none of them
   supporting sliding window encoding schemes [RFC8406].

3.3.  Hybrid access

   This use-case considers improving multiple path communications with
   network coding at the transport layer.  We propose an illustration
   for this scenario in Figure 4.  This use-case is inspired from the
   Broadband Access via Integrated Terrestrial Satellite Systems (BATS)
   project and has been published as an ETSI Technical Report
   [ETSITR2017].

   To cope with packet loss (due to either end-user mobility or
   physical-layer impairments), network coding could be introduced both
   at the CPE and at the concentrator.  Apart from packet losses, other
   gains could be envisioned, such as a better tolerance to out-of-order
   packets which occur when exploited links exhibit high asymetry in



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   terms of RTT.  Depending on the ground architecture
   [I-D.chin-nfvrg-cloud-5g-core-structure-yang] [SAT2017], some
   equipments might be hosting both SATCOM and cellular functions.

   -{}- : bidirectional link

                           +---+    +--------------+
                      +-{}-|SAT|-{}-|BACKBONE      |
   +----+    +---+    |    +---+    |+------------+|
   |End |-{}-|CPE|-{}-|             ||CONCENTRATOR||
   |User|    +---+    |    +---+    |+------------+|    +-----------+
   +----+             |-{}-|DSL|-{}-|              |-{}-|Application|
                      |    +---+    |              |    |Server     |
                      |             |              |    +-----------+
                      |    +---+    |              |
                      +-{}-|LTE|-{}-+--------------+
                           +---+

     Figure 4: Network architecture for an hybrid access using network
                                  coding

3.4.  Dealing with LAN losses

   This use-case considers the usage of network coding to cope with
   cases where the end user connects to the satellite terminal with a
   Wi-Fi link that exhibits losses.  In the case of encrypted end-to-end
   applications based on UDP, PEP cannot operate.  The Wi-Fi losses
   result in an end-to-end retransmission that would harm the quality of
   experience of the end user.  In this use-case, adding network coding
   techniques could prevent the end-to-end retransmission from occuring.

   The architecture is recalled in Figure 5.

 -{}- : bidirectional link
 -''- : Wi-Fi link
 C : where network coding techniques could be introduced

 +----+    +---------+    +---+    +--------+    +-------+    +--------+
 |End |    |Satellite|    |SAT|    |Physical|    |Access |    |Network |
 |user|-''-|Terminal |-{}-|   |-{}-|Gateway |-{}-|Gateway|-{}-|Function|
 +----+    +---------+    +---+    +--------+    +-------+    +--------+
    C                       C            C           C

        Figure 5: Network architecture for dealing with LAN losses







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3.5.  Dealing with varying channel conditions

   This use-case considers the usage of network coding to cope with
   cases where channel condition change in less than a second and the
   mechanisms that are exploited to adapt the physical-layer codes
   (Adaptative Coding and Modulation (ACM)) may not adapt the modulation
   and coding in time: remaining errors could be recovered with higher
   layer redundancy packets.  This use-case is mostly relevant when
   mobile users are considered or when the chosen band induces quick
   changes in channel condition (Q/V bands, Ka band, etc.).  Depending
   on the use-case (e.g., very high frequency bands, mobile users) or
   depending on the deployment use-cases (e.g., performance of the
   network between each individual block), the relevance of adding
   network coding is different.

   The architecture is recalled in Figure 6.

   -{}- : bidirectional link
   C : where network coding techniques could be introduced

   +---------+    +---+    +--------+    +-------+    +--------+
   |Satellite|    |SAT|    |Physical|    |Access |    |Network |
   |Terminal |-{}-|   |-{}-|Gateway |-{}-|Gateway|-{}-|Function|
   +---------+    +---+    +--------+    +-------+    +--------+
        C                       C            C           C

       Figure 6: Network architecture for dealing with varying link
                              characteristics

3.6.  Improving the gateway handovers

   This use-case considers the recovery of packets that may be lost
   during gateway handovers.  Whether this is for off-loading one given
   equipment or because the transmission quality is not the same on each
   gateway, changing the transmission gateway may be relevant.  However,
   packet losses can occur if the gateways are not properly synchronized
   or if the algorithm that is exploited to trigger gateway handovers is
   not properly tuned.  During these critical phases, network coding can
   be added to improve the reliability of the transmission and allow a
   seamless gateway handover.

   Figure 7 illustrates this use-case.









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   -{}- : bidirectional link
   !   : management interface
   C : where network coding techniques could be introduced
                                           C             C
                         +--------+    +-------+    +--------+
                         |Physical|    |Access |    |Network |
                    +-{}-|gateway |-{}-|gateway|-{}-|function|
                    |    +--------+    +-------+    +--------+
                    |                        !       !
   +---------+    +---+              +---------------+
   |Satellite|    |SAT|              | Control plane |
   |Terminal |-{}-|   |              | manager       |
   +---------+    +---+              +---------------+
                    |                        !       !
                    |    +--------+    +-------+    +--------+
                    +-{}-|Physical|-{}-|Access |-{}-|Network |
                         |gateway |    |gateway|    |function|
                         +--------+    +-------+    +--------+
                                           C             C

     Figure 7: Network architecture for dealing with gateway handover
                                  schemes

4.  Research challenges

   This section proposes a few potential approaches to introduce and use
   network coding in SATCOM systems.

4.1.  On the joint-use of network coding and congestion control in
      SATCOM systems

   SATCOM systems typically feature Performance Enhancing Proxy (PEP)
   RFC 3135 [RFC3135].  PEPs usually split end-to-end connections and
   forward transport or application layer packets to the satellite
   baseband gateway that deals with layer-2 and layer-1 encapsulations.
   PEP contributes to mitigate congestion in a SATCOM systems.  PEP
   could host network coding mechanisms and thus support use-cases that
   have been discussed in this document.

   Deploying network coding in the PEP could be relevant and independent
   from the specific characteristics of a SATCOM link.  This leads to
   research questions on the interaction between network coding and
   congestion control.








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4.2.  On the efficient usage of satellite resource

   The recurrent trade-off in SATCOM systems remains: how much overhead
   from redundant reliability packets can be introduced to guarantee a
   better end-user QoE while optimizing capacity usage ? At which layer
   this supplementary network coding should be added ?

   This problem has been tackled in the past for physical-layer code,
   but there remains questions on how to adapt the overhead for, e.g.,
   the quickly varying channel conditions use-case where ACM may not be
   reacting quickly enough.

4.3.  Interaction with virtualized satellite gateways and terminals

   Related to the foreseen virtualized network infrastructure, network
   coding could be easily deployed as VNF.  Next generation of SATCOM
   ground segments could rely on a virtualized environment.  This trend
   can also be seen in cellular networks, making these discussions
   extendable to other deployment scenarios
   [I-D.chin-nfvrg-cloud-5g-core-structure-yang].  As one example, the
   network coding VNF deployment in a virtualized environment is
   presented in [I-D.vazquez-nfvrg-netcod-function-virtualization].

   A research challenge would be the optimization of the NFV service
   function chaining, considering a virtualized infrastructure and other
   SATCOM specific functions, to guarantee efficient radio usage and
   easy-to-deploy SATCOM services.  Moreover, another challenge related
   to a virtualized SATCOM equipment is the management of limited
   buffered capacities.

4.4.  Delay/Disruption Tolerant Networks

   Communications among deep-space platforms and terrestrial gateways
   can be a challenge.  Reliable end-to-end (E2E) communications over
   such paths must cope with long delay and frequent link disruptions;
   indeed, E2E connectivity may be available only intermittently or
   never.  Delay/Disruption Tolerant Networking [RFC4838] is a solution
   to enable reliable internetworking space communications where both
   standard ad-hoc routing and E2E Internet protocols cannot be used.
   Moreover, DTN can also be seen as an alternative solution to transfer
   the data between a central PEP and a remote PEP.

   Coding enables E2E reliable communication over DTN with adaptive re-
   encoding, as proposed in [THAI15].  In this case, the use-cases
   proposed in Section 3.5 would legitimize the usage of coding within
   the DTN stack to improve the channel utilization and the E2E
   transmission delay.  In this context, the use of erasure coding
   techniques inside a Consultative Committee for Space Data Systems



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   (CCSDS) architecture has been specified in [CCSDS-131.5-O-1].  A
   research challenge would be on how such network coding can be
   integrated in the IETF DTN stack.

5.  Conclusion

   This document discuses some opportunities to introduce network coding
   techniques at a wider scale in satellite telecommunications systems.

   Even though this document focuses on satellite systems, it is worth
   pointing out that some scenarios proposed may be relevant to other
   wireless telecommunication systems.  As one example, the generic
   architecture proposed in Figure 1 may be mapped to cellular networks
   as follows: the 'network function' block gathers some of the
   functions of the Evolved Packet Core subsystem, while the 'access
   gateway' and 'physical gateway' blocks gather the same type of
   functions as the Universal Mobile Terrestrial Radio Access Network.
   This mapping extends the opportunities identified in this draft since
   they may be also relevant for cellular networks.

6.  Glossary

   The glossary of this memo extends the glossary of the taxonomy
   document [RFC8406] as follows:

   o  ACM : Adaptive Coding and Modulation;

   o  BBFRAME: Base-Band FRAME - satellite communication layer 2
      encapsulation work as follows: (1) each layer 3 packet is
      encapsulated with a Generic Stream Encapsulation (GSE) mechanism,
      (2) GSE packets are gathered to create BBFRAMEs, (3) BBFRAMEs
      contain information related to how they have to be modulated (4)
      BBFRAMEs are forwarded to the physical-layer;

   o  CPE: Customer Premises Equipment;

   o  COM: COMmunication;

   o  DSL: Digital Subscriber Line;

   o  DTN: Delay/Disruption Tolerant Network;

   o  DVB: Digital Video Broadcasting;

   o  E2E: End-to-end;

   o  ETSI: European Telecommunications Standards Institute;




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   o  FEC: Forward Erasure Correction;

   o  FLUTE: File Delivery over Unidirectional Transport;

   o  IntraF: Intra-Flow Coding;

   o  InterF: Inter-Flow Coding;

   o  IoT: Internet of Things;

   o  LTE: Long Term Evolution;

   o  MPC: Multi-Path Coding;

   o  NC: Network Coding;

   o  NFV: Network Function Virtualization;

   o  NORM: NACK-Oriented Reliable Multicast;

   o  PEP: Performance Enhancing Proxy [RFC3135] - a typical PEP for
      satellite communications include compression, caching and TCP
      acceleration;

   o  PLFRAME: Physical Layer FRAME - modulated version of a BBFRAME
      with additional information (e.g., related to synchronization);

   o  QEF: Quasi-Error-Free;

   o  QoE: Quality-of-Experience;

   o  QoS: Quality-of-Service;

   o  SAT: SATellite;

   o  SATCOM: generic term related to all kinds of SATellite
      COMmunication systems;

   o  SPC: Single-Path Coding;

   o  VNF: Virtual Network Function.

7.  Acknowledgements

   Many thanks to John Border, Stuart Card, Tomaso de Cola, Vincent
   Roca, Lloyd Wood and Marie-Jose Montpetit for their help in writing
   this document.




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8.  IANA Considerations

   This memo includes no request to IANA.

9.  Security Considerations

   Security considerations are inherent to any access network, and in
   particular SATCOM systems.  The use of FEC or Network Coding in
   SATCOM also comes with risks (e.g., a single corrupted redundant
   packet may propagate to several flows when they are protected
   together in an Inter-Flow coding approach, see section Section 3).
   However this is not specific to the SATCOM use-case and this document
   does not further elaborate on it.

10.  Informative References

   [ASMS2010]
              De Cola, T. and et. al., "Demonstration at opening session
              of ASMS 2010", Advanced Satellite Multimedia Systems
              (ASMS) Conference , 2010.

   [CCSDS-131.5-O-1]
              "Erasure correcting codes for use in near-earth and deep-
              space communications", CCSDS Experimental
              specification 131.5-0-1, 2014.

   [ETSITR2017]
              "Satellite Earth Stations and Systems (SES); Multi-link
              routing scheme in hybrid access network with heterogeneous
              links", ETSI TR 103 351, 2017.

   [I-D.chin-nfvrg-cloud-5g-core-structure-yang]
              Chen, C. and Z. Pan, "Yang Data Model for Cloud Native 5G
              Core structure", draft-chin-nfvrg-cloud-5g-core-structure-
              yang-00 (work in progress), December 2017.

   [I-D.vazquez-nfvrg-netcod-function-virtualization]
              Vazquez-Castro, M., Do-Duy, T., Romano, S., and A. Tulino,
              "Network Coding Function Virtualization", draft-vazquez-
              nfvrg-netcod-function-virtualization-02 (work in
              progress), November 2017.

   [RFC3135]  Border, J., Kojo, M., Griner, J., Montenegro, G., and Z.
              Shelby, "Performance Enhancing Proxies Intended to
              Mitigate Link-Related Degradations", RFC 3135,
              DOI 10.17487/RFC3135, June 2001,
              <https://www.rfc-editor.org/info/rfc3135>.




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   [RFC4838]  Cerf, V., Burleigh, S., Hooke, A., Torgerson, L., Durst,
              R., Scott, K., Fall, K., and H. Weiss, "Delay-Tolerant
              Networking Architecture", RFC 4838, DOI 10.17487/RFC4838,
              April 2007, <https://www.rfc-editor.org/info/rfc4838>.

   [RFC5740]  Adamson, B., Bormann, C., Handley, M., and J. Macker,
              "NACK-Oriented Reliable Multicast (NORM) Transport
              Protocol", RFC 5740, DOI 10.17487/RFC5740, November 2009,
              <https://www.rfc-editor.org/info/rfc5740>.

   [RFC6726]  Paila, T., Walsh, R., Luby, M., Roca, V., and R. Lehtonen,
              "FLUTE - File Delivery over Unidirectional Transport",
              RFC 6726, DOI 10.17487/RFC6726, November 2012,
              <https://www.rfc-editor.org/info/rfc6726>.

   [RFC8406]  Adamson, B., Adjih, C., Bilbao, J., Firoiu, V., Fitzek,
              F., Ghanem, S., Lochin, E., Masucci, A., Montpetit, M-J.,
              Pedersen, M., Peralta, G., Roca, V., Ed., Saxena, P., and
              S. Sivakumar, "Taxonomy of Coding Techniques for Efficient
              Network Communications", RFC 8406, DOI 10.17487/RFC8406,
              June 2018, <https://www.rfc-editor.org/info/rfc8406>.

   [SAT2017]  Ahmed, T., Dubois, E., Dupe, JB., Ferrus, R., Gelard, P.,
              and N. Kuhn, "Software-defined satellite cloud RAN",
              International Journal on Satellite Communnications and
              Networking vol. 36 - https://doi.org/10.1002/sat.1206,
              2017.

   [SHINE]    Pietro Romano, S. and et. al., "Secure Hybrid In Network
              caching Environment (SHINE) ESA project", ESA project ,
              2017 on-going.

   [THAI15]   Thai, T., Chaganti, V., Lochin, E., Lacan, J., Dubois, E.,
              and P. Gelard, "Enabling E2E reliable communications with
              adaptive re-encoding over delay tolerant networks",
              Proceedings of the IEEE International Conference on
              Communications http://dx.doi.org/10.1109/ICC.2015.7248441,
              June 2015.

Authors' Addresses

   Nicolas Kuhn (editor)
   CNES
   18 Avenue Edouard Belin
   Toulouse  31400
   France

   Email: nicolas.kuhn@cnes.fr



Kuhn & Lochin             Expires May 21, 2020                 [Page 14]


Internet-Draft    Network coding for satellite systems     November 2019


   Emmanuel Lochin (editor)
   ISAE-SUPAERO
   10 Avenue Edouard Belin
   Toulouse  31400
   France

   Email: emmanuel.lochin@isae-supaero.fr












































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