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

Internet Engineering Task Force                             N. Kuhn, Ed.
Internet-Draft                                                      CNES
Intended status: Informational                            E. Lochin, Ed.
Expires: May 16, 2019                                       ISAE-SUPAERO
                                                            Nov 12, 2018


                     Network coding and satellites
             draft-irtf-nwcrg-network-coding-satellites-02

Abstract

   This memo details a multi-gateway satellite system to identify
   multiple opportunities on how coding techniques could be deployed at
   a wider scale.

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
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   This Internet-Draft will expire on May 16, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Glossary  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  A note on satellite topology  . . . . . . . . . . . . . . . .   4
   3.  Status of reliability schemes in actually deployed satellite
       systems . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Details on the use cases  . . . . . . . . . . . . . . . . . .   6
     4.1.  Two way relay channel mode  . . . . . . . . . . . . . . .   7
     4.2.  Reliable multicast  . . . . . . . . . . . . . . . . . . .   7
     4.3.  Hybrid access . . . . . . . . . . . . . . . . . . . . . .   8
     4.4.  Dealing with varying capacity . . . . . . . . . . . . . .   9
     4.5.  Improving the gateway handovers . . . . . . . . . . . . .  10
   5.  Research challenges . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  Deployability in current SATCOM systems . . . . . . . . .  11
     5.2.  Interaction with virtualization . . . . . . . . . . . . .  11
     5.3.  Delay/Disruption Tolerant Networks  . . . . . . . . . . .  12
   6.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     10.2.  Informative References . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  17

1.  Introduction

   Guaranteeing both physical layer robustness and efficient usage of
   the radio resource has been in the core design of SATellite
   COMmunication (SATCOM) systems.  The trade-off often resided in how
   much redundancy a system adds to cope from link impairments, without
   reducing the good-put when the channel quality is high.  There is
   usually enough redundancy to guarantee a Quasi-Error Free
   transmission.  However, physical layer reliability mechanisms may not
   recover transmission losses (e.g. with a mobile user) and layer 2 (or
   above) re-transmissions induce 500 ms one-way delay with a
   geostationary satellite.  Further exploiting coding schemes at higher
   OSI-layers is an opportunity for releasing constraints on the
   physical layer in such cases and improving the performance of SATCOM
   systems.

   We have noticed an active research activity on coding and SATCOM in
   the past.  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 coding in these
   systems.



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   This document follows the taxonomy of coding techniques for efficient
   network communications [RFC8406].

1.1.  Glossary

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

   o  ACM : Adaptative 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 Premise Equipment;

   o  DTN: Delay/Disruption Tolerant Network;

   o  EPC: Evolved Packet Core;

   o  ETSI: European Telecommunications Standards Institute;

   o  PEP: Performance Enhanced Proxy - 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  SATCOM: generic term related to all kind of SATellite
      COMmunications systems;

   o  QoS: Quality-of-Service;

   o  QoE: Quality-of-Experience;

   o  VNF: Virtualized Network Function.

1.2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].






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2.  A note on satellite topology

   This section focuses on a generic description of the components
   composing a generic satellite system and their interaction.  A high
   level description of a multi-gateway satellites network is provided.
   There exist multiple SATCOM systems, such as those dedicated to
   broadcasting TV or to IoT applications: depending on the purpose of
   the SATCOM system, ground segments are specific.  This memo lays on
   SATCOM systems dedicated to Internet access that follows the DVB-S2/
   RCS2 standards.  In this context, the increase of the available
   capacity that is carried out to end users and the need for
   reliability results in the need for multiple gateways for one unique
   satellite platform.

   In this context, Figure 1 shows an example of a multi-gateway
   satellite system.  More details on a generic SATCOM ground segment
   architecture for a bi-directional Internet access can be found in
   [SAT2017].  We propose a multi-gateway system since some of the use-
   cases described in this document require multiple gateways.  In a
   multi-gateway system, some elements may be centralized and/or
   gathered: the relevance of one approach compared to another depends
   on the deployment scenario.  More information on these trade-off
   discussions can be found in [SAT2017].

   It is worth noting that some functional blocks aggregate the traffic
   coming from multiple users.  Even if coding schemes could be applied
   to any individual traffic, it could also work on an aggregate.
























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   +---------------------+
   | Application servers |
   +---------------------+
          ^     ^   ^
          |     |   |
          -----------------------------------
          v     v   v             v   v     v
   +------------------+         +------------------+
   | network function |         | network function |
   | (firewall, PEP)  |         | (firewall, PEP)  |
   +------------------+         +------------------+
       ^  ^                        ^        ^
       |  | IP packets             |        |
       v  v                        v        v
   +------------------+         +------------------+
   | access gateway   |         | access gateway   |
   +------------------+         +------------------+
          ^                                 ^
          | BBFRAMEs                        |
          v                                 v
   +------------------+         +------------------+
   | physical gateway |         | physical gateway |
   +------------------+         +------------------+
          ^                                 ^
          | PLFRAMEs                        |
          v                                 v
   +------------------+         +------------------+
   | outdoor unit     |         | outdoor unit     |
   +------------------+         +------------------+
          ^                                 ^
          | Satellite link                  |
          v                                 v
   +------------------+         +------------------+
   | sat terminals    |         | sat terminals    |
   +------------------+         +------------------+
          ^                                 ^
          |                                 |
          v                                 v
   +------------------+         +------------------+
   | end user         |         | end user         |
   +------------------+         +------------------+

    Figure 1: Data plane functions in a generic satellite multi-gateway
                                  system







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3.  Status of reliability schemes in actually deployed satellite systems

   Figure 2 presents the status of the reliability schemes deployment in
   satellite systems.  The information is based on the taxonomy document
   [RFC8406] and the notations are the following: End-to-End Coding
   (E2E), Network Coding (NC), Intra-Flow Coding (IntraF), Inter-Flow
   Coding (InterF), Single-Path Coding (SP) and Multi-Path Coding (MP).

   X1 embodies the source coding that could be used at application level
   for instance within QUIC or other video streaming applications: this
   is not specific to SATCOM systems, but is relevant for broadband
   Internet access discussions.

   X2 embodies the physical layer, applied to the PLFRAME, to optimize
   the satellite capacity usage: at the physical layer, FEC mechanisms
   can be exploited.  This aspect is not in the scope of the WG
   according to the taxonomoy document [RFC8406].

   +------+-------+---------+---------------+-------+
   |      | Upper | Middle  | Communication layers  |
   |      | Appl. | ware    |                       |
   +      +-------+---------+---------------+-------+
   |      |Source | Network | Packetization | PHY   |
   |      |coding | AL-FEC  | UDP/IP        | layer |
   +------+-------+---------+---------------+-------+
   |E2E   |   X1  |         |               |       |
   |NC    |       |         |               |       |
   |IntraF|   X1  |         |               |       |
   |InterF|       |         |               |   X2  |
   |SP    |   X1  |         |               |   X2  |
   |MP    |       |         |               |       |
   +------+-------+---------+---------------+-------+

        Figure 2: Reliability schemes in current satellite systems

   Reliability is an inherent part of the physical layer and usually
   achieved by using coding techniques.  Based on public information,
   coding does not seem to be widely used at higher OSI layers, other
   than at the application layer.

4.  Details on the use cases

   This section details use-cases where coding schemes could improve the
   overall performance of a SATCOM system (e.g. considering a more
   efficient usage of the satellite resource, delivery delay, delivery
   ratio).





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   It is worth noting that these use-cases focus more on the middleware
   (e.g. aggregation nodes) and packetization UDP/IP of Figure 2.
   Indeed, there are already lots of recovery mechanisms at the physical
   layer in currently deployed systems while E2E source coding are done
   at the application level.  In a multi-gateway SATCOM Internet access,
   the specific opportunities are more relevant in specific SATCOM
   components such as the "network function" block or the "access
   gateway" of Figure 1.

4.1.  Two way relay channel mode

   This use-case considers a two-way communication between end users,
   through a satellite link.  We propose an illustration of this
   scenario in Figure 3.

   Satellite terminal A (resp.  B) transmits a flow A (resp.  B) to a
   server hosting NC capabilities, which forward a combination of the
   two flows to both terminals.  This results in non-negligible
   bandwidth saving and has been demonstrated at ASMS 2010 in Cagliari
   [ASMS2010].  Moreover, with On-Board Processing satellite payloads,
   the coding operations could be done at the satellite level, thus
   reducing the end-to-end delay of the communication.

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

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

     Figure 3: Network architecture for two way relay channel with NC

4.2.  Reliable multicast

   This use-case considers adding redundancy to a multicast flow
   depending on what has been received by different end-users, resulting
   in non-negligible scarce resource saving.  We propose an illustration
   for this scenario in Figure 4.




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   A multicast flow (M) is forwarded to both satellite terminals A and
   B.  However packet Ni (resp.  Nj) get lost at terminal A (resp.  B),
   and terminal A (resp.  B) returns a negative acknowledgement 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 NACK-Oriented Reliable Multicast (NORM) [RFC5740] in situations
   where a feedback is possible and desirable, or FLUTE/ALC [RFC6726]
   when it is not the case.  Note that currently both NORM nor FLUTE/ALC
   are limited to block coding, none of them supporting sliding window
   encoding schemes [RFC8406].

   -Li}- : packet indicated the loss of packet i of a multicast flow
   ={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 4: Network architecture for a reliable multicast with NC

4.3.  Hybrid access

   This use-case considers the use of multiple path management with
   coding at the transport level to increase the reliability and/or the
   total capacity (using multiple path does not guarantee an improvement
   of both the reliability and the total bandwidth).  We propose an
   illustration for this scenario in Figure 5.  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].  It is worth nothing that this kind of
   architecture is also discussed in the TCPM working group
   [I-D.ietf-tcpm-converters].

   To cope with packet loss (due to either end-user mobility or physical
   layer impairments), coding could be introduced in both the CPE and at
   the concentrator.





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  -{}- : bidirectional link

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

       Figure 5: Network architecture for an hybrid access using NC

4.4.  Dealing with varying capacity

   This use-case considers the usage of coding to overcome cases where
   the wireless link characteristics quickly change overtime and where
   the physical layer codes could not be made robust in time.  This is
   particularly relevant when end users are moving and the channel shows
   important variations [IEEEVT2001].

   The architecture is recalled in Figure 6.  In these cases, Adaptative
   Coding and Modulation (ACM) may not adapt the modulation and coding
   accordingly and remaining errors could be recovered with higher
   layers redundancy packets.  The coding schemes could be applied at
   the access gateway or the network function block levels to increase
   the reliability of the transmission.  This use-case is mostly
   relevant for when mobile users are considered or when the chosen band
   induce a required physical layer coding that may change over time (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 coding is different.  Then, depending
   on the OSI level at which coding is applied, the impact on the
   satellite terminal is different: coding may be applied on IP packets
   or on layer-2 proprietary format packets.












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   -{}- : bidirectional link

   +---------+    +---+    +--------+    +-------+    +--------+
   |Satellite|    |SAT|    |Physical|    |Access |    |Network |
   |Terminal |-{}-|   |-{}-|gateway |-{}-|gateway|-{}-|function|
   +---------+    +---+    +--------+    +-------+    +--------+
        NC                      NC           NC          NC

       Figure 6: Network architecture for dealing with varying link
                          characteristics with NC

4.5.  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,
   if gateways are not properly synchronized, this may result in packet
   loss.  During these critical phases, coding can be added to improve
   the reliability of the transmission and propose a seamless gateway
   handover.  In this case, the coding could be applied at either the
   access gateway or the network function block.  The entity responsible
   for taking the decision to change the communication gateway and
   changing the routes is the control plane manager; this entity
   exploits a management interface.

   An example architecture for this use-case is showed in Figure 7.  It
   is worth noting that depending on the ground architecture
   [I-D.chin-nfvrg-cloud-5g-core-structure-yang] [SAT2017], some
   equipment might be communalised.





















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   -{}- : bidirectional link
   !   : management interface
                                          NC            NC
                         +--------+    +-------+    +--------+
                         |Physical|    |Access |    |Network |
                    +-{}-|gateway |-{}-|gateway|-{}-|function|
                    |    +--------+    +-------+    +--------+
                    |                        !       !
   +---------+    +---+              +---------------+
   |Satellite|    |SAT|              | Control plane |
   |Terminal |-{}-|   |              | manager       |
   +---------+    +---+              +---------------+
                    |                        !       !
                    |    +--------+    +-------+    +--------+
                    +-{}-|Physical|-{}-|Access |-{}-|Network |
                         |gateway |    |gateway|    |function|
                         +--------+    +-------+    +--------+
                                          NC            NC

     Figure 7: Network architecture for dealing with gateway handover
                              schemes with NC

5.  Research challenges

5.1.  Deployability in current SATCOM systems

   SATCOM systems typically feature Performance Enhancement Proxy
   RFC 3135 [RFC3135] which could be relevant to host coding mechanisms
   and thus support the use-cases that have been discussed in Section 4.
   PEP usually split TCP end-to-end connections and forward TCP packets
   to the satellite baseband gateway that deals with layer 2 and layer 1
   encapsulations.  Deploying coding schemes at the TCP level in these
   equipments could be relevant and independent from the specificities
   of a SATCOM link.  That being said, we can notice a research issue in
   the recurrent trade-off in SATCOM systems that is related to the
   amount of reliability that you introduce in the first transmission to
   guarantee a better end-user QoE and the usage of the scarce resource.

5.2.  Interaction with virtualization

   Related to the foreseen virtualized network infrastructure, the
   coding schemes could be proposed as Virtual Network Function (VNF)
   and their deployability enhanced.  The architecture for the next
   generation of SATCOM ground segments would rely on a virtualized
   environment.  This trend can also be seen, making the discussions on
   the deployability of coding in SATCOM extendable to other deployment
   scenarios [I-D.chin-nfvrg-cloud-5g-core-structure-yang].  As one
   example, the coding VNF functions deployment in a virtualized



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   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 an efficient radio resource
   utilization and easy to deploy SATCOM services.

5.3.  Delay/Disruption Tolerant Networks

   In the context of deep-space communications, establishing
   communications from terrestrial gateways to satellite platforms can
   be a challenge.  Indeed, reliable end-to-end (E2E) communications
   over such links must cope with long delay and frequent link
   disruptions.  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.  The transport of data over such networks requires the use
   of replication, erasure codes and multipath protocol schemes [WANG05]
   [ZHANG06] to improve the bundle delivery ratio and/or delivery delay.
   For instance, transport protocols such as LTP [RFC5326] for long
   delay links with connectivity disruptions, use Automatic Repeat-
   reQuest (ARQ) and unequal error protection to reduce the amount of
   non-mandatory re-transmissions.  The work in [TOURNOUX10] proposed
   upon LTP a robust streaming method based on an on-the-fly coding
   scheme, where encoding and decoding procedures are done at the source
   and destination nodes, respectively.  However, each link path loss
   rate may have various order of magnitude and re-encoding at an
   intermediate node to adapt the redundancy can be mandatory to prevent
   transmission wasting.  This idea has been put forward in
   [I-D.zinky-dtnrg-random-binary-fec-scheme] and
   [I-D.zinky-dtnrg-erasure-coding-extension], where the authors
   proposed an encoding process at intermediate DTN nodes to explore the
   possibilities of Forward Error Correction (FEC) schemes inside the
   bundle protocol [RFC5050].  In this context, the use of erasure
   coding inside a Consultative Committee for Space Data Systems (CCSDS)
   architecture has been specified in [CCSDS-131.5-O-1].

   In the context of the deep-space communications, coding could be
   improved by, e.g. using a feedback path: when a return path is
   available, on-the-fly schemes can be used to enable E2E reliable
   communication over DTN with adaptive re-encoding as proposed in
   [THAI15].  That being said, DTN can also be seen as an alternative
   solution to transfer the data between a central PEP and a remote PEP.
   In this case, the use-cases proposed in Section 4.4 would legitimate
   the usage of coding within the DTN stack to improve the channel
   utilization and the E2E transmission delay.





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6.  Conclusion

   This document presents the current deployment of coding in some
   satellite telecommunications systems along with a discussion on the
   multiple opportunities to introduce these techniques at a wider
   scale.

   Even if this document focuses on satellite systems, it is worth
   pointing out that the 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 gather 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.

7.  Acknowledgements

   Many thanks to Tomaso de Cola, Vincent Roca, Lloyd Wood and Marie-
   Jose Montpetit for their help in writting this document.

8.  IANA Considerations

   This memo includes no request to IANA.

9.  Security Considerations

   Security considerations are inherent to any access network.  SATCOM
   systems introduce standard security mechanisms.  In particular, there
   are some specificities related to the fact that all users under the
   coverage can record all the packets that are being transmitted, such
   as in LTE networks.  On the specific scenario of NC in SATCOM
   systems, there are no specific security considerations.

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.







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10.2.  Informative References

   [ASMS2010]
              De Cola, T. and et. al., "Demonstration at opening session
              of ASMS 2010", ASMS , 2010.

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

   [CCSDS-FDP]
              "CCSDS File Delivery Protocol, Recommendation for Space
              Data System Standards", CCSDS 727.0-B-4, Blue Book num. 3,
              2007.

   [COLA11]   De Cola, T., Paolini, E., Liva, G., and G. Calzolari,
              "Reliability options for data communications in the future
              deep-space missions", Proceedings of the IEEE vol. 99
              issue 11, 2011.

   [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.ietf-tcpm-converters]
              Bonaventure, O., Boucadair, M., Gundavelli, S., and S.
              Seo, "0-RTT TCP Convert Protocol", draft-ietf-tcpm-
              converters-04 (work in progress), October 2018.

   [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.

   [I-D.zinky-dtnrg-erasure-coding-extension]
              Zinky, J., Caro, A., and G. Stein, "Bundle Protocol
              Erasure Coding Extension", draft-zinky-dtnrg-erasure-
              coding-extension-00 (work in progress), August 2012.





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   [I-D.zinky-dtnrg-random-binary-fec-scheme]
              Zinky, J., Caro, A., and G. Stein, "Random Binary FEC
              Scheme for Bundle Protocol", draft-zinky-dtnrg-random-
              binary-fec-scheme-00 (work in progress), August 2012.

   [IEEEVT2001]
              Fontan, F., Vazquez-Castro, M., Cabado, C., Garcia, J.,
              and E. Kubista, "Statistical modeling of the LMS channel",
              BEER Transactions on Vehicular Technology vol. 50 issue 6,
              2001.

   [LACAN08]  Lacan, J. and E. Lochin, "Rethinking reliability for long-
              delay networks", International Workshop on Satellite and
              Space Communications , October 2008.

   [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>.

   [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>.

   [RFC5050]  Scott, K. and S. Burleigh, "Bundle Protocol
              Specification", RFC 5050, DOI 10.17487/RFC5050, November
              2007, <https://www.rfc-editor.org/info/rfc5050>.

   [RFC5326]  Ramadas, M., Burleigh, S., and S. Farrell, "Licklider
              Transmission Protocol - Specification", RFC 5326,
              DOI 10.17487/RFC5326, September 2008,
              <https://www.rfc-editor.org/info/rfc5326>.

   [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>.







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   [RFC6816]  Roca, V., Cunche, M., and J. Lacan, "Simple Low-Density
              Parity Check (LDPC) Staircase Forward Error Correction
              (FEC) Scheme for FECFRAME", RFC 6816,
              DOI 10.17487/RFC6816, December 2012,
              <https://www.rfc-editor.org/info/rfc6816>.

   [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", Int.
              J. Satell. Commun. Network. vol. 36, 2017.

   [SUNDARARAJAN08]
              Sundararajan, J., Shah, D., and M. Medard, "ARQ for
              network coding", IEEE Int. Symp. on Information Theory ,
              July 2008.

   [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 , June 2015.

   [TOURNOUX10]
              Tournoux, P., Lochin, E., Leguay, J., and J. Lacan, "On
              the benefits of random linear coding for unicast
              applications in disruption tolerant networks", Proceedings
              of the IEEE International Conference on Communications ,
              2010.

   [TOURNOUX11]
              Tournoux, P., Lochin, E., Lacan, J., Bouabdallah, A., and
              V. Roca, "On-the-fly erasure coding for real-time video
              applications", IEEE Trans. on Multimedia vol. 13 issue 4,
              August 2011.

   [WANG05]   Wang, Y. and et. al., "Erasure-coding based routing for
              opportunistic networks", Proceedings of the ACM SIGCOMM
              workshop on Delay-tolerant networking , 2005.







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   [ZHANG06]  Zhang, X. and et. al., "On the benefits of random linear
              coding for unicast applications in disruption tolerant
              networks", Proceedings of the 4th International Symposium
              on Modeling and Optimization in Mobile, Ad Hoc and
              Wireless Networks , 2006.

Authors' Addresses

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

   Email: nicolas.kuhn@cnes.fr


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

   Email: emmanuel.lochin@isae-supaero.fr



























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