Internet DRAFT - draft-bernini-nfvrg-vnf-orchestration
draft-bernini-nfvrg-vnf-orchestration
NFV Research Group G. Bernini
Internet-Draft G. Landi
Intended status: Informational Nextworks
Expires: October 12, 2017 D. Lopez
Telefonica
P. Aranda Gutierrez
UC3M
April 10, 2017
VNF Pool Orchestration For Automated Resiliency in Service Chains
draft-bernini-nfvrg-vnf-orchestration-04
Abstract
Network Function Virtualisation (NFV) aims at evolving the way
network operators design, deploy and provision their networks by
leveraging on standard IT virtualisation technologies to move and
consolidate a wide range of network functions and services onto
industry standard high volume servers, switches and storage. The
primary target for operators, stimulated by the recent updates on NFV
and SDN, is the network edge. In fact, operators are considering
their future datacentres and Points of Presence (PoPs) as
increasingly dynamic infrastructures where Virtualised Network
Functions (VNFs) and on-demand chained services with high elasticity
will be deployed.
This document presents an orchestration framework for automated
deployment of highly available VNF chains. Resiliency of VNFs and
chained services is a key requirement for operators to improve, ease,
automate and speed up services lifecycle management. The proposed
VNFs orchestration framework is also positioned with respect to
current NFV and Service Function Chaining (SFC) architectures and
solutions.
Status of This Memo
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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 October 12, 2017.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. VNF Pool Orchestration for Resilient Virtual Appliances . . . 4
3.1. Problem Statement . . . . . . . . . . . . . . . . . . . . 5
3.2. Orchestration Framework . . . . . . . . . . . . . . . . . 6
3.2.1. Orchestrator . . . . . . . . . . . . . . . . . . . . 8
3.2.2. SDN Controller . . . . . . . . . . . . . . . . . . . 8
3.2.3. Service Function Path Manager . . . . . . . . . . . . 9
3.2.4. Edge Configurator . . . . . . . . . . . . . . . . . . 10
3.3. Resiliency Control Functions for Chained VNFs . . . . . . 10
4. Positioning in Existing NFV and SFC Frameworks . . . . . . . 12
4.1. Mapping into NFV Architecture . . . . . . . . . . . . . . 12
4.2. Mapping into SFC Architecture . . . . . . . . . . . . . . 13
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
Current Telco infrastructures are facing the rapid development of the
cloud market, which includes a broad range of emerging virtualised
services and distributed applications. Network Function
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Virtualisation (NFV) is gaining wide interest across operators as a
means to evolve the way networks are operated and provisioned, with
network functions and services traditionally integrated in hardware
devices executed in virtualised environments.
A Virtualised Network Function (VNF) provides the same function as
its non virtualised equivalent (e.g. firewall, load balancer) but is
deployed as a software instance running on general purpose servers
using virtualisation technologies. The main idea, therefore, is to
run network functions in datacentres or commodity network nodes that
are, in some cases, close to the end user premises. With NFV,
network functions are moved from specialised hardware devices to
self-contained virtual machines running in general purpose servers.
These virtualised functions can be deployed in multiple instances or
moved to various locations in the network, adapting themselves to
traffic dynamicity and customer demands without the overhead cost and
management of installing new equipment.
Operator networks are populated with a large and increasing variety
of proprietary software and hardware tools and appliances. The
deployment of new network services in operational environments is
often a complex and costly procedure, where additional physical space
and power are required to accommodate new boxes. Additionally,
current hardware-based appliances rapidly reach end of life. This
requires that much of the design integration and deployment cycle be
repeated with little revenue benefit. In this context, the
transition of network functions and appliances from hardware to
software solutions by means of NFV promises to address and overcome
these hindrances for network operators.
The considerations above are valid for stand-alone VNFs running
independently. However, additional challenges and requirements raise
for network operators when services offered to customers are built by
the composition of multiple VNFs. In this case, the deployment and
provisioning of each (virtual) service component for the customer
needs to be coordinated with the other VNFs, applying control
functions to steer the traffic through them following a predefined
order (i.e. according to the specific service function path). An
orchestration framework capable of coordinating the automated
deployment, configuration, provisioning and chaining of multiple VNFs
would ease the management of the whole lifecycle of services offered
to customers. Additionally, when dealing with virtualised functions,
resiliency and high availability of chained services pose additional
requirements for a VNF orchestration framework, in terms of detection
of software failures at various levels (including hypervisors and
virtual machines, hardware failure), and dynamic and intellingent
reaction (virtual appliance migration, deployment of new VNFs, re-
adapt the VNF chain).
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This document presents an orchestration framework for automated
deployment of high available VNF chains, and introduces its
architecture and building blocks. Resiliency for both stand-alone
VNFs and chained services is considered in this document as a key
control function based on VNF pool concepts. The proposed VNF pool
orchestration framework is also positioned with respect to approaches
and architectures currently defined for Network Function
Virtualisation and Service Function Chaining (SFC).
2. Terminology
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 [RFC2119].
The following acronyms are used in this document:
NFV: Network Function Virtualisation.
SDN: Software Defined Networking.
VNF: Virtualised Network Function.
SFC: Service Function Chaining.
CPE: Customer Premise Equipment.
VPN: Virtual Private Network.
EMS: Element Management System.
PoP: Point of Presence.
VM: Virtual Machine.
3. VNF Pool Orchestration for Resilient Virtual Appliances
The telco market is rapidly moving towards an "Everything as a
Service" model, where the virtualisation of traditionally in-the-box
network functions can benefit from Software Defined Networking (SDN)
tools and technologies. As said, the recent updates and proposed
solutions on NFV and SDN is practically bringing, from an operator
perspective, a deep evolution on how the network edge is architected,
operated and provisioned, since that is the place where VNFs and
virtual services can be deployed and provisioned close to the
customers. Operators target to evolve their datacentres and PoPs
into increasingly dynamic infrastructures where VNFs and chained
services can be deployed with high availability and high elasticity
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to scale up and down while optimizing performances and resources
utilization.
This section introduces the VNF pool orchestration framework for the
deployment, provisioning and chaining of resilient virtual appliances
and services within operator data-centres proposed in this document.
3.1. Problem Statement
The orchestration framework proposed in this document aims at solving
some of the challenges that operators face when, trying to apply the
base NFV concepts, they replace hardware devices implementing well-
known network functions with software-based virtual appliances. In
particular, this VNF orchestration framework targets an automated,
flexible and elastic provisioning of service chains within operators'
datacentres.
When operators need to compose and chain multiple VNFs to provision a
given service to the customer, they need to operate network and
computing resources in a coordinated way, and above all to implement
control mechanisms and procedures to steer the traffic through the
different VNFs and the customer sites. As an example, the
virtualisation of the Customer Premises Equipment (CPE) is emerging
as one of the first applications of the Network Functions
Virtualisation (NFV) architecture that is currently being
commercialized by several software (and hardware) vendors. It has
the potential to generate a significant impact on the operators
businesses. The term virtual CPE (vCPE) refers to the execution in a
virtual environment of the network functions that traditionally
integrated in hardware gears at customer premises, like BGP speakers,
firewall, NAT, etc.
Different scenarios and use cases exist for the vCPE. Currently, the
typical scenario is the vCPE in the PoP, that actually provides
softwarization and shift to the first PoP of the operator for those
network functions normally deployed at customer premises (e.g. NAT,
Firewall, etc.). The goal is to manage the whole LAN environment of
the customer, while preserving QoE of its services, providing added
value services to users not willing to get involved with technology
issues, and reducing maintenance trouble tickets and the need for in-
house problem solving. In addition, the vCPE can be used in the
operator's datacenter to implement in software those chained network
functions to provision automated VPN services for customers
[VCPE-T2], in order to dynamically and automatically extend existing
L3 VPNs (e.g. connecting remote customer sites) to incorporate new
virtual assets (like virtual machines) into a private cloud.
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As additional requirements for the proposed orchestration framework,
the use of VNFs opens new challenges concerning the reliability of
provided virtual services. When network functions are deployed on
monolithic hardware platforms, the lifecycle of individual services
is strictly bound to the availability of the physical device, and
management tools may detect outages and migrate affected services to
new instances deployed on backup hardware. When introducing VNFs,
individual network functions may still fail, but with more risk
factors such as software failure at various levels, including
hypervisors and virtual machines, hardware failure, and virtual
appliance migration. Moreover, when considering chains of VNFs, the
management and control tools used by the operators have to consider
and apply reliability mechanisms at the service level, including
transparent migration to backup VNFs and synchronization of state
information. In this context, VNF pooling mechanisms and concepts
are valid and applicable, thus considering VNF instances grouped as
pools to provide the same function in a reliable way.
3.2. Orchestration Framework
The VNF pool orchestration framework proposed in this document aims
to provide automated functions for the deployment, provisioning and
composition of resilient VNFs within operators' datacentres.
Figure Figure 1 presents the high level architecture, including
building blocks and functional components.
This VNF pool orchestration framework is built around two key
components: the orchestrator and the SDN controller. The
orchestrator includes all the functions related to the management,
coordination, and control of VNFs instantiation, configuration and
composition. It is the component at the highest level of the
architecture and represents the access point to the VNF pool
orchestration framework for the operator. On the other hand, the SDN
controller provides dynamic traffic steering and flexible network
provisioning within the datacenter as needed by the VNF chains. The
basic controller functions are augmented by a set of enhanced network
applications deployed on top, that might be themselves control and
management VNFs for operator use (i.e. not related to customers and
users functions).
Therefore, the architecture depicted in Figure Figure 1 is a
practical demonstration of how SDN and NFV technologies and concepts
can be integrated to provide substantial benefits to network
operators in terms of robustness, ease of management, control and
provisioning of their network infrastructures and services. SDN and
NFV are clearly complementary solutions for enabling virtualisation
of network infrastructures, services and functions while supporting
dynamic and flexible network traffic engineering.
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+----------------------------------------------+
| Orchestrator |
+-----+----------------+----------------+------+
| | |
V V V
+------------+ +-------------+ +-------------+
| | | | | |
| VNF Pool | | Service Fcn | | Edge |
| Manager | | Path Mgr | |Configurator |
| | | | | |
+-----+------+ +------+------+ +------+------+
| | |
V V V
+----------------------------------------------+
| SDN Controller |
+--------------+---+----+---------------+------+
+.......................+ | | | |
: +--------+ \ | | | +-----+
: |+-------++ :| +-----+---+----+----+ |
: +| || :\ | +-----------------+-+ +---+----+
: /|| VNF1 || : | | | +---------------+-+-+ | |
: / || || :..+ | | | Virtual | | +-------+ Edge |
: / ++-------+| : : | | | Switch(es) | | +-------+ Router |
: / +---+----+ : :| +-+-+---------------+ | | | |
: / | : :\ +-+-----------------+ | +--------+
: +--+-----+ | : : | +-----+---+---+-----+
: |+-------++ | : : \ | | |
: || || | : : | | | |
: || VNF2 || | : : \---------+---+---+------+
: || || | : : | |
: ++-------+| | : : | |
: +--+-+---+ | : : | Virtual Compute |
: \ +----+---+ : : | Infrastructure |
: \|+-------++ : : | |
: +| || : : | |
: || VNF3 || : : /------------------------+
: || || : : |
: ++-------+| : : |
: +--------+ : : |
:Service Chain "X" : : /
+.......................+ : |
:Service Chain "Y" :/
+........................+
Figure 1: VNF Pool Orchestration Framework Architecture.
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SDN focuses on network programmability, traffic steering and multi-
tenancy by means of a common, open, and dynamic abstraction of
network resources. NFV targets a progressive migration of network
elements, network appliances and fixed function boxes into VMs that
can be ran on commodity hardware, enabling the benefits of cloud and
datacentres to be applied to network functions.
3.2.1. Orchestrator
The VNF orchestrator implements a set of functions to seamlessly
control and manage in a coordinated way the instantiation and
deployment of VNFs on one hand, and their composition and chaining to
steer the traffic through them on the other. It is fully controlled
and operated by the network operator, and basically it is the highest
control and orchestration layer that sits above all the softwarized
and virtualised components in the proposed architecture.
Therefore the VNF orchestrator provides a consistent way to access
the system and provision chains of VNFs to the operator. It exposes
a set of primitives to instantiate, configure VNFs and compose them
according to the specific service chain requirements. Practically,
it aims at enabling an efficient and dynamic management of operator's
infrastructure resources with great flexibility by means of a
consistent set of APIs.
To enable this, the VNF orchestrator can be seen as a composition of
several internal functionalities, each providing a given coordination
function needed to orchestrate the lower layer control and management
functions depicted in Figure Figure 1 (i.e. VNF chain configuration,
VNF pool provisioning, etc.). In practice, the VNF orchestrator
needs to include at least an internal component to manage the
instantiation and configuration of stand-alone VNFs (e.g. implemented
by a self-contained VM) that might be directly interfaced with the
physical servers in the datacenter. And also a dedicated component
for programmatic coordination and provisioning of VNF chains is
needed to properly orchestrate the traffic steering through VNFs
belonging to the same service chain. This should also provide multi-
tenant functionalities and maintain isolation across VNF chains
deployed for different customers. It is then clear that the VNF
orchestrator is the overall coordinator of the proposed framework,
and it drives all the lower layer components that implement the
actual control logic.
3.2.2. SDN Controller
The SDN controller provides the logic for network control,
provisioning and monitoring. It is the component where the SDN
abstraction happens. This means it exposes a set of primitives to
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configure the datacenter network according to the requirements of the
VNF chains to be provisioned, while hiding the specific technology
constraints and capabilities of the software switches and edge
routers underneath. The deployment of an SDN controller allows to
implement a software driven VNF orchestration, with flexible and
programmable network functions for service chaining and resilient
virtual appliances.
At its southbound interface, the SDN controller interfaces with
software switches running in servers, physical switches
interconnecting them and edge routers connecting the datacenter with
external networks. Multiple control protocols can be used at this
southbound interface to actually provision the datacenter network and
enable traffic steering through VNFs, including OpenFlow, OVSDB,
NETCONF and others.
Therefore the SDN controller provides the basic network provisioning
functions needed by upper layer coordination functions to perform
service chain and VNF pool-wide actions. Indeed, the logic and the
state at the service level is only maintained and coordinated by
network applications on top of the SDN controller.
3.2.3. Service Function Path Manager
The service function path manager is deployed as a bridging component
between the orchestrator and the SDN controller, and it is mostly
dedicated to the implementation of VNF chaining and composition
logic. It computes a suitable path to interconnect the involved VNFs
(already instantiated and identified by the orchestrator) and
forwards the network configuration request to the SDN controller for
each new VNF chain requested by the orchestrator.
Following the datacenter service chains and related traffic types
defined in [I-D.ietf-sfc-dc-use-cases], the service function path
manager should implement its coordination logic to support both
north-south and east-west chains. The former refer to network
traffic staying within the datacenter but coming from a remote
datacenter or a user through the edge router connecting to an
external network. In this case, the service function path manager
should also coordinate with the edge configurator to properly
provision the datacenter edge router. Moreover, this north-south
case may also refer to VNF chains spanning multiple datacentres, thus
requiring a further inter-datacenter coordination between service
function path managers and orchestrators. These coordination
functions are out of the scope of this document. On the other hand,
the east-west chains refer to VNFs treating network traffic that do
not exit the datacenter. For both cases, the service function path
manager (in combination with the SDN controller) should implement and
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support proper service chains encapsulation solutions
[I-D.ietf-sfc-nsh] to isolate and segregate traffic related to VNF
chains belonging to different tenants.
Different deployment models may exist for the service function path
manager: a dedicated configurator for each chain, or a single
configurator for all the VNF chains. In the first approach, the
orchestrator needs to implement some coordination logic related to
the dynamic instantiation of configurators when new VNF chains are
provisioned.
3.2.4. Edge Configurator
The edge configurator is a network control application deployed on
top of the SDN controller. Its main role is to coordinate the
provisioning and configuration of the edge router for those north-
south VNF chains exiting the datacenter. In particular, it keeps the
binding between the traffic steered through the VNFs and the related
network service outside the datacenter terminated at the edge router
(e.g. a L3 VPN, VLAN, VXLAN, VRF etc), possibly considering the
service chain encapsulation implemented within the VNF chain. The
mediation of the SDN controller allows to support a variety of
control and management protocols for the actual configuration of the
datacenter edge router.
3.3. Resiliency Control Functions for Chained VNFs
In the proposed orchestration architecture, the resiliency control
functions that have been identified as a key feature for a flexible
and dynamic provisioning of chained VNF services are implemented by
the VNF pool manager depicted in Figure Figure 1. It is the entity
that manages and coordinates VNFs reliability providing high
availability and resiliency features at both stand-alone and chained
VNFs level.
The deployment of VNF based services requires moving the resiliency
capabilities and mechanisms from physical network devices (which are
typically highly available and often specialized) to entities (like
self-contained VMs) running VNFs in the context of pools of
virtualised resources. When moving towards a resilient approach for
VNF deployment and operation, in line with ETSI NFV Resiliency
Requirements (NFV-REL001), the generic high availability requirements
to be matched are translated into:
Service continuity: when a hardware failure or capacity limits
(memory and CPU) occur on platforms hosting VMs (and therefore
VNFs), it is necessary to migrate VNFs to other VMs and/or
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hardware platforms to guarantee service continuity with minimum
impact on the users
Topological transparency: the hand-over between live and backup VNFs
must be implemented in a transparent way for the user and also for
the service chain itself. The backup VNF instances need to
replicate the necessary information (configuration, addressing,
etc.) so that the network function is taken over without any
topological disruption (i.e. at the VNF chain level)
Load balancing or scaling: migration of VNF instances may also
happen for load-balancing purposes (e.g. for CPU, memory overload
in virtualised platforms) or scaling of network services (with
VNFs moved to new hardware platforms). In both cases the working
network function is moved to a new VNF instance and the service
continuity must be maintained.
Auto scale of VNFs instances: when a VNF requires increased resource
allocation to improve overall service performance, the network
function could be distributed across multiple VMs, and to
guarantee the performance improvement dedicated pooling mechanisms
for scaling up or down resources to each VNF in a consistent way
are needed.
Multiple VNF resiliency classes: each type of end-to-end service
(e.g. web, financial backend, video streaming, etc.) has its own
specific resiliency requirements for the related VNFs. While for
operators it is not easy to achieve service resiliency SLAs
without building to peak, a basic set of VNF resiliency classes
can be defined to identify some metrics, such as: if a VNF needs
status synchronization; fault detection and restoration time
objective (e.g. real-time); service availability metrics; service
quality metrics; service latency metrics for VNF chain components.
The aim of the VNF pool orchestration presented in this document is
to address the above requirements by introducing the VNF pool manager
that follows the principles of the IETF VNFPOOL architecture [I-
D.zong-vnfpool-arch], where a pool manager coordinates the
reliability of stand-alone VNFs, by selecting the active instance and
interacting with the Service Control Entity for consistent end-to-end
service chain reliability and provisioning. In the VNF pool
orchestration architecture illustrated in Figure Figure 1, the
Service Control Entity is implemented by the combination of the
orchestrator (for overall coordination of service chains) and the VNF
chain configuration (for actual provisioning and coordination of
individual service chains).
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Different deployment models may exist for the VNF pool manager: a
dedicated manager for each VNF chain, or a single one for all the
chains.
In terms of offered resiliency functionalities, the VNF pool manager
provides some post-configuration functions to instantiate VNFs (as
self-contained VMs) with the desired degree of reliability and
redundancy. This translates into further actions to create and
configure additional VMs as backups, therefore building a pool for
each VNF in the chain.
The VNF pool manager is conceived to offer several types and degrees
of reliability functions. First, it provides specific functions for
the persistence of VNFs configuration, including making periodic
snapshots of the VMs running the VNF. Moreover, at runtime (i.e.
with the service chain in place), it monitors the operational status
and performances of the master VNFs VMs, and collects notifications
about VMs status, e.g. by registering as an observer to dedicated
services offered by the virtualisation platform used within the
virtual compute infrastructure. Moreover, VNF pool manager reacts to
any failure condition by autonomously replacing the master VNF with
one of its backup on the pool, basically implementing a swap of VMs
for service chain recovery purposes. Thus, the VNF pool manager also
takes care in coordination with the service function path manager of
implementing those resiliency mechanisms at the chain level. Two
options have been identified so far: cold recovery and hot recovery.
In the former, backup VNFs, properly configured with the same master
configuration, are kept ready (but switched off) to be started when
the master dies. In this case the recovery time depends on the
specific VNF and its type of function, e.g. it may depend on
convergence time for a virtual BGP router. In the hot recovery,
active backup VNFs are kept synchronized with the master ones, and
the recovery of the service chain (mostly performed at the service
function path manager) in case of failure is faster than cold
recovery.
4. Positioning in Existing NFV and SFC Frameworks
4.1. Mapping into NFV Architecture
For the presented solution to be integrated in the ETSI NFV reference
architecture, some modifications need to be applied to it, with main
focus on the Management and Orchestration (MANO) functions. The VNF
pools replace the VNFs in the architecture. They are then controlled
by the Element Management System (EMS) on the northbound. So the EMS
has to be made VNFPOOL aware. Additional elements that need to
support the mechanisms proposed by VNFPOOL are the VNF managers,
which need to implement the resiliency and VNF scaling
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(up-/downscale) functions. This has also implications on the NFV
Orchestrator, which has to be aware of the augmented functionality
offered by the VNF Manager. In fact, the NFV Orchestrator also
provides primitives for VNFs chaining, matching the Service Control
Entity in the VNFPool architecture. Therefore, even if ETSI NFV MANO
does not include explicitely SDN, the Edge Configurator, and part of
the Service Function Path Manager features might be also covered by
an augmented NFV Orchestrator.
4.2. Mapping into SFC Architecture
[I-D.ietf-sfc-architecture] describes the Service Function Chaining
(SFC) architecture. It describes the concept of a service function
(SF) and how to chain SFs and provides only little detail of the SFC
control plane, which is responsible with the coordination of the SFs
and their stitching into SFCs. The combination of orchestrator,
service function path manager and VNF pool manager functionalities
described in this document cover most of the functions expected from
the SFC control plane.
The interaction with the SFC Classifier is left for further study.
We expect the VNFPOOL architecture to leverage on it to make sure
that all VNFPOOL instances will be served traffic on during scale-up
and that no traffic will be lost during scale-down.
5. IANA Considerations
This draft does not have any IANA consideration.
6. Security Considerations
Security issues related to VNF pool orchestration and resiliency of
service chains are left for further study.
7. Acknowledgements
This work has been partially supported by the European Commission
through the H2020 5G Crosshaul (The integrated fronthaul/backhaul,
grant agreement no:H2020-671598) and Selfnet (Framework for Self-
organized network management in virtualized and software defined
networks, grant agreement no:H2020-671672) projects. The views
expressed here are those of the authors only. The European
Commission is not liable for any use that may be made of the
information in this document.
Authors would also like to thank V. Maffione and G. Carrozzo from
Nextworks for valuable discussions and contributions to the topics
addressed in this document.
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8. References
8.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
8.2. Informative References
[I-D.ietf-sfc-dc-use-cases]
Surendra, S., Tufail, M., Majee, S., Captari, C., and S.
Homma, "Service Function Chaining Use Cases In Data
Centers", draft-ietf-sfc-dc-use-cases-06 (work in
progress), February 2017.
[I-D.ietf-sfc-architecture]
Halpern, J. and C. Pignataro, "Service Function Chaining
(SFC) Architecture", draft-ietf-sfc-architecture-11 (work
in progress), July 2015.
[I-D.ietf-sfc-nsh]
Quinn, P. and U. Elzur, "Network Service Header", draft-
ietf-sfc-nsh-12 (work in progress), February 2017.
[I-D.zong-vnfpool-problem-statement]
Zong, N., Dunbar, L., Shore, M., Lopez, D., and G.
Karagiannis, "Virtualized Network Function (VNF) Pool
Problem Statement", draft-zong-vnfpool-problem-
statement-06 (work in progress), July 2014.
[VCPE-T2] G. Bernini, G. Carrozzo, P. A. Gutierrez, D. R. Lopez, ,
"Virtualising the Network Edge: Virtual CPE for the
datacenter and the PoP", European Conference on Networks
and Communications , June 2014.
Authors' Addresses
Giacomo Bernini
Nextworks
Via Livornese 1027
San Piero a Grado, Pisa 56122
Italy
Phone: +39 050 3871600
Email: g.bernini@nextworks.it
Bernini, et al. Expires October 12, 2017 [Page 14]
Internet-Draft VNF Orchestration April 2017
Giada Landi
Nextworks
Via Livornese 1027
San Piero a Grado, Pisa 56122
Italy
Phone: +39 050 3871600
Email: g.landi@nextworks.it
Diego R. Lopez
Telefonica
C. Zurbaran, 12
Madrid 28010
Spain
Email: diego.r.lopez@telefonica.com
Pedro A. Aranda Gutierrez
Universidad Carlos III Madrid
Leganes 28911
Spain
Email: paranda@it.uc3m.es
Bernini, et al. Expires October 12, 2017 [Page 15]
