Network Coding Function Virtualization
draft-vazquez-nfvrg-netcod-function-virtualization-00
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| Authors | M.A. Vazquez-Castro , Tan Do-Duy , Paresh Saxena , Magnus Vikstrom | ||
| Last updated | 2016-11-14 | ||
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draft-vazquez-nfvrg-netcod-function-virtualization-00
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.
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Task Force (IETF). Note that other groups may also distribute
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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
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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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