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Versions: 00 01 02                                                      
NFVRG                                               M. A. Vazquez-Castro
Internet-Draft                                                 T. Do-Duy
Intended status: Informational                                       UAB
Expires: May 17, 2017                                          P. Saxena
                                                             M. Vikstrom
                                                                   AnsuR
                                                       November 13, 2016


                 Network Coding Function Virtualization
         draft-vazquez-nfvrg-netcod-function-virtualization-00

Abstract

   This document describes network coding as a network function.  It
   also describes how a network coding function can be virtualized and
   integrated with virtual network functions architectures.  The network
   coding function is not a traditionally implemented network function
   in dedicated hardware as those that have triggered network function
   virtualization.  It refers to a novel network functionality that
   generalizes classic packet-level end-to-end coding.  Classic packet-
   level end-to-end coding helps in the provision of quality of service
   by trading off delay and reliability.  Network coding goes beyond
   that by enabling in-network optimized re-encoding, which can provide
   both throughput gains and diverse network-controlled degrees of
   reliability.  Consequently, a virtualized network coding function can
   serve as a flow engineering tool over virtualized networks (e.g. over
   network slices).

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 17, 2017.






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Copyright Notice

   Copyright (c) 2016 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
   Provisions Relating to IETF Documents
   (http://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.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Network coding as a network function  . . . . . . . . . . . .   5
   4.  Virtual Network Coding Function . . . . . . . . . . . . . . .   5
     4.1.  Virtualization of flows . . . . . . . . . . . . . . . . .   5
     4.2.  Integration with ETSI NFV architecture  . . . . . . . . .   6
     4.3.  Example . . . . . . . . . . . . . . . . . . . . . . . . .   7
   5.  Conclusions . . . . . . . . . . . . . . . . . . . . . . . . .   8
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     9.1.  Normative Information References  . . . . . . . . . . . .   9
     9.2.  Conceptual ground basis . . . . . . . . . . . . . . . . .   9
     9.3.  Application references  . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Network coding(NC) is a novel technology that can be seen as the
   generalization of classic point to point coding to coding for network
   flows.  As with classic coding, both information theoretical and
   algebraic codes literature provide the conceptual solid basis of NC.
   Such conceptual basis has clarified NC benefits and corresponding
   tradeoffs, which need to be considered in practical implementations
   of the technology.

   NC does not replace end-to-end (packet-level block) coding, which is
   a well-established technology for the per-flow provision of quality
   of service by trading off delay and reliability.  Instead, NC
   provides coding within and across network flows relying on in-network



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   re-encoding based on service-intent-oriented policy strategies.  By
   means of such policy strategies, the provision of quality of service
   that NC can offer can be tailored according to desired network
   service intent.

   For its operation, NC relies on having access to network, computation
   and storage resources throughout the network.  Such novel networking,
   computational and storage ingredients of a coding technology calls
   for novel practical design approaches to truly exploit the potential
   capabilities of NC.

   On the other hand, Network Function Virtualization (NFV) and NC can
   be seen as different ways to address different challenges in the
   design of upcoming network technologies.  Moreover, NC is not a
   traditionally implemented network function in dedicated hardware,
   which are the network functions that have triggered the design of NFV
   architectures.  However, in this document we show the feasibility and
   benefits of virtualizing the network coding function.

   The objective of this document is not to explain network coding
   technology.  The interested reader should find this information
   outside this document.

   The objective of this document is fundamentally two fold.  First, we
   show that NC can be designed as a (modular) network function.  The
   modularity is convenient for the user and is given as sets of
   elementary functionalities (toolboxes) that are defined independent
   of the physical network.  Second, we show that the NC function
   requirements of connectivity, computation and storage resources find
   a natural practical design solution in the integration of the NC
   function with available NFV architectural frameworks.  Such solution
   is described here and it combines network protocol-driven and system
   modular-driven design approaches.

   The resulting Virtual Network Coding Function (VNCF) can be useful
   for upcoming networking needs derived from network virtualization.

2.  Conventions used in this document

   The following terms defined in this document can be found in the ETSI
   NFV [etsi_gs_nfv_002_v1.2.1] and the IETF [I-D.irtf-nwcrg-network-
   coding-taxonomy].

   Coherent Network Coding: Source and destination nodes know network
   topology and coding operations at intermediate nodes.






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   Noncoherent Network Coding: Source and destination nodes do not know
   network topology and intermediate coding operations.  In this case,
   random network coding can be applied.

   Flow: A stream of physical packets logically grouped from the network
   coding perspective.  These packets may come from the same application
   (in that case they are identified by the five-tuple: source and
   destination IP address, transport protocol ID, and source and
   destination port of the transport protocol), or come from the same
   source host (in which case they are identified by the 3-tuple source
   and destination IP address, Type of Service (TOS) or Diffserv code
   point(DSCP)).  This distinction depends on the use-case where network
   coding is applied.

   Intra-flow coding: Network coding over payloads belonging to the same
   flow.

   Inter-flow coding: Network coding over payloads belonging to multiple
   flows.

   End-to-end coding : Transport stream is coded and decoded at end-
   points.

   Coding node: Node performing coding operations.

   Virtualized Infrastructure Manager (VIM): functional block that is
   responsible for controlling and managing the NFVI compute, storage
   and network resources, usually within one operator's Infrastructure
   Domain.

   Virtualized Network Function (VNF): implementation of a Network
   Function that can be deployed on a Network Function Virtualization
   Infrastructure (NFVI).

   Virtualized Network Function Manager (VNFM): functional block that is
   responsible for the lifecycle management of VNF.

   NFV Infrastructure (NFVI): totality of all hardware and software
   components which build up the environment in which VNFs are deployed.

   NFV Orchestrator (NFVO): functional block that manages the Network
   Service (NS) lifecycle and coordinates the management of NS
   lifecycle, VNF lifecycle (supported by the VNFM) and NFVI resources
   (supported by the VIM) to ensure an optimized allocation of the
   necessary resources and connectivity.

   NFV Management and Orchestration (NFV-MANO): functions collectively
   provided by NFVO, VNFM, and VIM.



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3.  Network coding as a network function

   NC design involves different domains.  We can identify at least three
   domains:

   Coding domain - domain for the design of network coding codebooks,
   coherent or noncoherent encoding/decoding schemes, performance
   benchmarks, appropriate mathematical-to-logic maps, etc.  This is a
   domain fundamentally designed by coding theorists.

   Functional domain - domain for the design of the functional
   properties of NC to achieve the desired design requirements upon
   abstractions of networks and systems.  This domain jointly requires
   to consider physical-logical abstraction, identification of network
   coding application to either inter-flow or intra-flow network coding,
   service intent and related networking for the provision of quality of
   service.

   Protocol domain - domain for the design of physical signaling/
   transporting of the network coded information flow as one way or
   interactive protocols.

   The functional domain can be designed interpreting NC as a network
   function.  In order to provide the designer with sufficient
   flexibility, NC elementary functionalities can be grouped as a set of
   toolboxes that the designer can use.  We define the following three
   toolboxes:

   o  Coding/Re-encoding/Decoding Functionalities (CRDF).

   o  Flow Engineering Functionalities (FEF) performing optimization of
      available network resources to optimally perform NC to meet the
      service design targets depending on the (statistical) status of
      the networks (congestion, link failures, etc).

   o  Physical/Abstraction Functionalities (PAF) performing interaction
      with available storage and computation physical resources that are
      abstracted by the other toolboxes.

4.  Virtual Network Coding Function

4.1.  Virtualization of flows

   An important differentiating aspect of NC with respect to traditional
   networking technologies is the following.  A network flow for a NC
   network function is understood as a stream of physical packets
   logically grouped from the network coding perspective.




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   NC can optimize the NC operation abstracting such physical flow as a
   mathematical model, which can be subject of computational
   manipulation.  This makes NC to be naturally integrated into a
   virtualized framework of abstract entities such as virtual network or
   network slices.  This is because in the NC case, not only the network
   and resources are abstracted, but also the stream of packets is
   abstracted.

   Consequently, when interpreting NC as a functionality provided to the
   network, NC function virtualization simply consists of integrating
   the NC functional toolboxes described in the previous section into
   existing architectural NFV frameworks.  The virtualization of the
   network flow is managed by the NC function (CRDF toolbox), and the
   virtualization of all the functionalities described in Section 3 has
   no difference with respect to any other network function.

4.2.  Integration with ETSI NFV architecture

   Figure 1 shows our proposed virtual NC network function (VNCF).  It
   is integrated with the ETSI NFV architecture given the abstracted
   underlying physical system/network as part of NFVI.

   The integration naturally includes too exchanges between VNCF and
   NFV-MANO over reference points.

   Clearly, the functionalities of the FEF toolbox need to interact with
   the NFVO, VNFM, and VIM.  Note that the NFVO two main
   responsibilities of orchestration of NFVI resources across VIMs and
   the life-cycle management of network services, fit perfectly the
   needs of the FEF and PAF toolboxes.  Specifically, the FEF can obtain
   available network, connectivity and computation resources, geo-
   statistical status of the networks such as congestion, link failures,
   etc.  With these, NC operation can be optimized to meet the service
   design targets given the service-specific design constraints.  The
   optimization may result into manipulation of the (non-physical) flows
   and other flow engineering policies.  On the other hand, the FEF can
   interact with the VIM to obtain the allocation, upgrade, release, etc
   of NFVI resources.













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        +-------------------------------------------+  +---------------+
        |   Virtualized Network Functions (VNFs)    |  |               |
        |  -------   -------   -------   -------    |  |               |
        |  |     |   |     |   |     |   |     |    |  |               |
        |  | VNF |   | VNF |   |VNCF |   | VNF |    |  |               |
        |  |     |   |     |   |     |   |     |    |  |               |
        |  -------   -------   -------   -------    |  |               |
        +-------------------------------------------+  |               |

        +-------------------------------------------+  |               |
        |         NFV Infrastructure (NFVI)         |  |      NFV      |
        | -----------    -----------    ----------- |  |  Management   |
        | | Virtual |    | Virtual |    | Virtual | |  |      and      |
        | | Compute |    | Storage |    | Network | |  | Orchestration |
        | -----------    -----------    ----------- |  |               |
        | +---------------------------------------+ |  |               |
        | |         Virtualization Layer          | |  |               |
        | +---------------------------------------+ |  |               |
        | +---------------------------------------+ |  |               |
        | | -----------  -----------  ----------- | |  |               |
        | | | Compute |  | Storage |  | Network | | |  |               |
        | | -----------  -----------  ----------- | |  |               |
        | |          Hardware resources           | |  |               |
        | +---------------------------------------+ |  |               |
        +-------------------------------------------+  +---------------+


   Figure 1: ETSI NFV framework with one VNCF box as part of the set of
                              available VNFs.

4.3.  Example

   We describe here a high-level example of a general procedure of
   interaction between the VNCF and the NFV-MANO.  The NFV-MANO has
   repositories that hold different information regarding network
   services (NSs) and VNFs (VNCF is part of VNFs).  There are four types
   of repositories as follows:

   o  VNF catalogue represents the repository of all usable VNF
      packages, supporting the creation and management of the VNF
      packages.

   o  NS catalogue represents the repository of all usable NSs.

   o  NFV instances is the repository that holds details of all VNF
      instances and NS instances, represented by either a VNF record or
      a NS record, respectively, during the execution of VNF/NS life-
      cycle management operations.



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   o  NFVI resources is the repository that holds information about NFVI
      resources utilized for the establishment of NS and VNF instances.

   Assume a network abstracted as a set of N coding nodes, each with
   encoding/re-encoding/decoding and (possibly) multi-link connectivity.
   A user of the VNCF wants to provide an ultra-reliable service (e.g.
   mission-critical communications) to the N nodes.  The performance
   objectives are given as a set of N reliability and delay objective
   performance metrics, which are geo-location dependent.  We call this
   VNCF instantiation as a virtual geo-network coding function (VGNCF),
   which is activated and its management and orchestration take place.

   A detailed interaction with the architectural blocks (some under
   definition) is as follows.

   o  TBD

5.  Conclusions

   This memo presents a preliminary version of proposal for the design
   of NC as a network function.  It is also discussed that it can be
   virtualized and integrated into a NFV architecture.

6.  Acknowledgements

   The authors want to thank Dr. Harald Skinnemoen for useful comments
   and discussions.  The first author wants to thank Dr. Carlos J.
   Bernardos and Luis M.  Contreras for useful discussions.

   The authors also want to acknowledge the following ongoing projects.

   1.  GEO-VISION - GNSS driven EO and Verifiable Image and Sensor
       Integration for mission-critical Operational Networks.  EU funded
       project under the call H2020-GALILEO-2014-1 by the European
       Global Navigation Satellite Systems Agency (project reference
       641451).

   2.  SatNetCode - Satellite Network-Coding for high performance,
       semantic-aware mission-critical visual communications.  This
       project is funded by the European Space Agency.

   3.  HENCSAT - Highly Efficient Network Coding for Satellite
       Applications Test-bed.  This project is funded by the European
       Space Agency.







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7.  IANA Considerations

   This memo includes no request to IANA.

8.  Security Considerations

   This memo includes no Network Coding Function Virtualization -
   specific security definitions yet.

9.  References

9.1.  Normative Information References

   [etsi_gs_nfv_002_v1.2.1]
              "Network Function Virtualisation (NFV); Architectural
              Framework", 2014.

   [etsi_nvf_whitepaper]
              "Network Functions Virtualisation (NFV). White Paper 2",
              2014.

   [I-D.irtf-nwcrg-network-coding-taxonomy]
              Firoiu, V., Adamson, B., Roca, V., Adjih, C., Bilbao, J.,
              Fitzek, F., Masucci, A., and M. Montpetit, "Network Coding
              Taxonomy", draft-irtf-nwcrg-network-coding-taxonomy-01
              (work in progress), October 2016.

   [RFC6363]  Watson, M., Begen, A., and V. Roca, "Forward Error
              Correction (FEC) Framework", RFC 6363, 2011.

9.2.  Conceptual ground basis

   [AHL00]    Ahlswede, R., Cai, N., Y. R. Li, S., and R. W. Yeung,
              "Network information flow", in IEEE Trans. Inform. Theory,
              vol. 46, pp. 1204-1216, July 2000.

   [KOE03]    Koetter, R. and M. Medard, "An algebraic approach to
              network coding", in IEEE/ACM Trans. on Networking, vol.
              11, n. 5., pp. 782-795, October 2003.

   [LI03]     Y.R.Li, S., W. Yeung, R., and N. Cai, "Linear network
              coding", in IEEE Trans. Inform. Theory, vol. 49, n. 2.,
              pp. 371-381, February 2003.








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9.3.  Application references

   [ALE13]    Alegre-Godoy, R. and M. A. Vazquez-Castro, "Spatial
              Diversity with Network Coding for ON/OFF Satellite
              Channels", in IEEE Communications Letters, vol. 17, No. 8,
              pp. 1612-1615, August 2013.

   [ALE15]    Alegre-Godoy, R. and M. A. Vazquez-Castro, "Network Coded
              Multicast over Multi-beam Satellite Systems", in
              Mathematical Problems in Engineering, vol. 2015, Article
              ID 364234, May 2015.

   [DO16.1]   Do-Duy, T. and M. A. Vazquez-Castro, "Design of
              Virtualized Network Coding Functionality foR Reliability
              Control of Communication Services over Satellite",
              submitted to Special Issue on Network Coding.
              International Journal of Satellite Communications and
              Networking, 2016.

   [Do16.2]   Do-Duy, T. and M. A. Vazquez-Castro, "Network coding
              function virtualization", in IEEE 17th International
              Workshop on Signal Processing Advances in Wireless
              Communications (SPAWC), September 2016, INVIED PAPER.

   [HAN15]    Hansen, J., E. Lucani, D., Krigslund, J., Medard, M., and
              F. H. P. Fitzek, "Network coded software defined
              networking: enabling 5G transmission and storage
              networks", in IEEE Communications Magazine, 2015.

   [HEI09]    Heide, J., V. Pedersen, M., H. P. Fitzek, F., and T.
              Larsen, "Network Coding for Mobile Devices - Systematic
              Binary Random Rateless Codes", in ICC Workshops, 2009.

   [SAX15]    Saxena, P. and M. A. Vazquez-Castro, "DARE: DoF-Aided
              Random Encoding for Network Coding over Lossy Line
              Networks", in IEEE Communications Letters, vol. 19, No. 8,
              pp. 1374-1377, August 2015.

   [SZA15]    Szabo, D., Nemeth, F., Sonkoly, B., Gulyas, A., and F. H.
              P. Fitzek, "Towards the 5G revolution: A software defined
              network architecture exploiting network coding as a
              service", in SIGCOMM Comput. Commun, 2015.

   [VAZ15.1]  A. Vazquez-Castro, M., "A Geometric Approach to Dynamic
              Network Coding", in Information Theory Workshop, Jeju,
              Korea, October 2015.





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   [VAZ15.2]  A. Vazquez-Castro, M., "Subspace coding over Fq-linear
              erasure satellite channels", in 12th International
              Symposium on Wireless Communication Systems, pp. 216-220,
              August 2015.

   [VAZ15.3]  A. Vazquez-Castro, M. and P. Saxena, "Network Coding over
              Satellite: From Theory to Design and Performance", in
              Volume 154 of the series Lecture Notes of the Institute
              for Computer Sciences, Social Informatics and
              Telecommunications Engineering, pp. 315-327, September
              2015, INVITED PAPER.

Authors' Addresses

   M.A. Vazquez-Castro
   Autonomus University of Barcelona
   Campus de Bellaterra
   Barcelona, 08391
   Spain

   Email: angeles.vazquez@uab.es


   Tan Do-Duy
   Autonomus University of Barcelona
   Campus de Bellaterra
   Barcelona, 08391
   Spain

   Email: tan.doduy@uab.es


   Paresh Saxena
   AnsuR Technologies
   Martin Linges Vei 25, Fornebu
   Oslo, 1364
   Norway

   Email: paresh.saxena@ansur.es


   Magnus Vikstrom
   AnsuR Technologies
   Martin Linges Vei 25, Fornebu
   Oslo, 1364
   Norway

   Email: magnus@ansur.no



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