NFVRG/SDNRG groups CJ. Bernardos
Internet-Draft UC3M
Intended status: Informational A. Rahman
Expires: January 7, 2016 JC. Zuniga
InterDigital
LM. Contreras
P. Aranda
TID
July 6, 2015
Gap Analysis on Network Virtualization Activities
draft-bernardos-nfvrg-gaps-network-virtualization-01
Abstract
Network Function Virtualization (NFV) and Software Defined Networking
(SDN) are changing the way the telecommunications sector will deploy,
extend and operate their networks. These new technologies aim at
reducing the overall costs by outsourcing communication services from
specific hardware in the operators' core to server farms scattered in
datacenters (i.e. compute and storage virtualization). In addition,
the connecting networks are fundamentally affected in they way they
route, process and control traffic(i.e. network virtualization).
Virtualization is becoming a trend which is being adopted in many
scenarios for different purposes. This document overviews existing
efforts around virtualization at the IETF/IRTF, focusing on those
related to NFV and SDN. These efforts are mapped to the most
relevant architectures being defined outside IETF, namely at the ETSI
NFV ISG, the ETSI MEC ISG and the ONF.
The main goal of this document is to serve as a survey of the
different efforts that have been taken and are currently taking place
at IETF and IRTF in regards to network virtualization, putting them
into context considering efforts by other SDOs, and identifying
current gaps that can be tackled at IETF or researched at the IRTF.
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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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
working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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 January 7, 2016.
Copyright Notice
Copyright (c) 2015 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
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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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Network Function Virtualization . . . . . . . . . . . . . 5
3.2. Software Defined Networking . . . . . . . . . . . . . . . 7
3.3. Mobile Edge Computing . . . . . . . . . . . . . . . . . . 10
4. Network Virtualization at IETF/IRTF . . . . . . . . . . . . . 10
4.1. SFC WG . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2. NVO3 WG . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3. DMM WG . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.4. I2RS WG . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.5. BESS WG . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.6. VNFpool BoF . . . . . . . . . . . . . . . . . . . . . . . 15
4.7. TEAS WG . . . . . . . . . . . . . . . . . . . . . . . . . 15
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4.8. NFV RG . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.9. SDN RG . . . . . . . . . . . . . . . . . . . . . . . . . 16
5. Summary of Gaps . . . . . . . . . . . . . . . . . . . . . . . 17
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Normative References . . . . . . . . . . . . . . . . . . 18
9.2. Informative References . . . . . . . . . . . . . . . . . 19
Appendix A. The mobile network use case . . . . . . . . . . . . 20
A.1. The 3GPP Evolved Packet System . . . . . . . . . . . . . 20
A.2. Virtualizing the 3GPP EPS . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction
The telecommunications sector is experiencing a major revolution that
will shape the way networks and services are designed and deployed
for the next decade. We are witnessing an explosion in the number of
applications and services demanded by users, which are now really
capable of accessing them on the move. In order to cope with such a
demand, some network operators are now following a cloud computing
paradigm, enabling the reduction of the overall costs by outsourcing
communication services from specific hardware in the operator's core
to server farms scattered in datacenters. These services have
different characteristics if compared with conventional IT services
that have to be taken into account in this cloudification process.
Also the transport network is affected in that it is evolving to a
more sophisticated form of IP architecture with trends like
separation of control and data plane traffic, and more fine-grained
forwarding of packets (beyond looking at the destination IP address)
in the network to fulfill new business and service goals.
Virtualization of functions also provides operators with tools to
deploy new services much faster, as compared to the traditional use
of monolithic and tightly integrated dedicated machinery. As a
natural next step, mobile network operators need to re-think how to
evolve their existing network infrastructures and how to deploy new
ones to address the challenges posed by the increasing customers'
demands, as well as by the huge competition among operators. All
these changes are triggering the need for a modification in the way
operators and infrastructure providers operate their networks, as
they need to significantly reduce the costs incurred in deploying a
new service and operating it. Some of the mechanisms that are being
considered and already adopted by operators include: sharing of
network infrastructure to reduce costs, virtualization of core
servers running in data centers as a way of supporting their load-
aware elastic dimensioning, and dynamic energy policies to reduce the
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monthly electricity bill. However, this has proved to be tough to
put in practice, and not enough. Indeed, it is not easy to deploy
new mechanisms in a running operational network due to the high
dependency on proprietary (and sometime obscure) protocols and
interfaces, which are complex to manage and often require configuring
multiple devices in a decentralized way.
Network Function Virtualization (NFV) and Software Defined Networking
(SDN) are changing the way the telecommunications sector will deploy,
extend and operate their networks. This document provides a survey
of the different efforts that have taken and are currently taking
place at IETF and IRTF in regards of network virtualization, looking
at how they relate to the ETSI NFV ISG, ETSI MEC ISG and ONF
architectural frameworks. Based on this analysis, we also go a step
farther, identifying which are the potential work areas where IETF/
IRTF can work on to complement the complex network virtualization map
of technologies being standardized today.
2. Terminology
The following terms used in this document are defined by the ETSI NVF
ISG, and the ONF and the IETF:
NFV Infrastructure (NFVI): totality of all hardware and software
components which build up the environment in which VNFs are
deployed
NFV Management and Orchestration (NFV-MANO): functions
collectively provided by NFVO, VNFM, and VIM.
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.
OpenFlow protocol (OFP).
Service Function Chain (SFC): for a given service, the abstracted
view of the required service functions and the order in which they
are to be applied. This is somehow equivalent to the Network
Function Forwarding Graph (NF-FG) at ETSI.
Service Function Path (SFP): the selection of specific service
function instances on specific network nodes to form a service
graph through which an SFC is instantiated.
virtual EPC (vEPC).
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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 Virtualisation
Infrastructure (NFVI).
Virtualized Network Function Manager (VNFM): functional block that
is responsible for the lifecycle management of VNF.
3. Background
3.1. Network Function Virtualization
The ETSI ISG NFV is a working group which, since 2012, aims to evolve
quasi-standard IT virtualization technology to consolidate many
network equipment types into industry standard high volume servers,
switches, and storage. It enables implementing network functions in
software that can run on a range of industry standard server hardware
and can be moved to, or loaded in, various locations in the network
as required, without the need to install new equipment. To date,
ETSI NFV is by far the most accepted NFV reference framework and
architectural footprint. The ETSI NFV framework architecture
framework is composed of three domains (Figure 1):
o Virtualized Network Function, running over the NFVI.
o NFV Infrastructure (NFVI), including the diversity of physical
resources and how these can be virtualized. NFVI supports the
execution of the VNFs.
o NFV Management and Orchestration, which covers the orchestration
and life-cycle management of physical and/or software resources
that support the infrastructure virtualization, and the life-cycle
management of VNFs. NFV Management and Orchestration focuses on
all virtualization specific management tasks necessary in the NFV
framework.
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+-------------------------------------------+ +---------------+
| Virtualized Network Functions (VNFs) | | |
| ------- ------- ------- ------- | | |
| | | | | | | | | | | |
| | VNF | | VNF | | VNF | | 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
The NFV architectural framework identifies functional blocks and the
main reference points between such blocks. Some of these are already
present in current deployments, whilst others might be necessary
additions in order to support the virtualization process and
consequent operation. The functional blocks are (Figure 2):
o Virtualized Network Function (VNF).
o Element Management (EM).
o NFV Infrastructure, including: Hardware and virtualized resources,
and Virtualization Layer.
o Virtualized Infrastructure Manager(s) (VIM).
o NFV Orchestrator.
o VNF Manager(s).
o Service, VNF and Infrastructure Description.
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o Operations and Business Support Systems (OSS/BSS).
+--------------------+
+-------------------------------------------+ | ---------------- |
| OSS/BSS | | | NFV | |
+-------------------------------------------+ | | Orchestrator +-- |
| ---+------------ | |
+-------------------------------------------+ | | | |
| --------- --------- --------- | | | | |
| | EM 1 | | EM 2 | | EM 3 | | | | | |
| ----+---- ----+---- ----+---- | | ---+---------- | |
| | | | |--|-| VNF | | |
| ----+---- ----+---- ----+---- | | | manager(s) | | |
| | VNF 1 | | VNF 2 | | VNF 3 | | | ---+---------- | |
| ----+---- ----+---- ----+---- | | | | |
+------|-------------|-------------|--------+ | | | |
| | | | | | |
+------+-------------+-------------+--------+ | | | |
| NFV Infrastructure (NFVI) | | | | |
| ----------- ----------- ----------- | | | | |
| | Virtual | | Virtual | | Virtual | | | | | |
| | Compute | | Storage | | Network | | | | | |
| ----------- ----------- ----------- | | ---+------ | |
| +---------------------------------------+ | | | | | |
| | Virtualization Layer | |--|-| VIM(s) +-------- |
| +---------------------------------------+ | | | | |
| +---------------------------------------+ | | ---------- |
| | ----------- ----------- ----------- | | | |
| | | Compute | | Storage | | Network | | | | |
| | | hardware| | hardware| | hardware| | | | |
| | ----------- ----------- ----------- | | | |
| | Hardware resources | | | NFV Management |
| +---------------------------------------+ | | and Orchestration |
+-------------------------------------------+ +--------------------+
Figure 2: ETSI NFV reference architecture
3.2. Software Defined Networking
The Software Defined Networking (SDN) paradigm pushes the
intelligence currently residing in the network elements to a central
controller implementing the network functionality through software.
In contrast to traditional approaches, in which the network's control
plane is distributed throughout all network devices, with SDN the
control plane is logically centralized. In this way, the deployment
of new characteristics in the network no longer requires of complex
and costly changes in equipment or firmware updates, but only a
change in the software running in the controller. The main advantage
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of this approach is the flexibility it provides operators with to
manage their network, i.e., an operator can easily change its
policies on how traffic is distributed throughout the network.
The most visible of the SDN protocol stacks is the OpenFlow protocol
(OFP), which is maintained and extended by the Open Network
Foundation (ONF). Originally this protocol was developed
specifically for IEEE 802.1 switches conforming to the ONF OpenFlow
Switch specification. As the benefits of the SDN paradigm have
reached a wider audience, its application has been extended to more
complex scenarios such as Wireless and Mobile networks. Within this
area of work, the ONF is actively developing new OFP extensions
addressing three key scenarios: (i) Wireless backhaul, (ii) Cellular
Evolved Packet Core (EPC), and (iii) Unified access and management
across enterprise wireless and fixed networks.
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+----------+
| ------- |
| |Oper.| | O
| |Mgmt.| |<........> -+- Network Operator
| |Iface| | ^
| ------- | +----------------------------------------+
| | | +------------------------------------+ |
| | | | --------- --------- --------- | |
|--------- | | | | App 1 | | App 2 | ... | App n | | |
||Plugins| |<....>| | --------- --------- --------- | |
|--------- | | | Plugins | |
| | | +------------------------------------+ |
| | | Application Plane |
| | +----------------------------------------+
| | A
| | |
| | V
| | +----------------------------------------+
| | | +------------------------------------+ |
|--------- | | | ------------ ------------ | |
|| Netw. | | | | | Module 1 | | Module 2 | | |
||Engine | |<....>| | ------------ ------------ | |
|--------- | | | Network Engine | |
| | | +------------------------------------+ |
| | | Controller Plane |
| | +----------------------------------------+
| | A
| | |
| | V
| | +----------------------------------------+
| | | +--------------+ +--------------+ |
| | | | ------------ | | ------------ | |
|----------| | | | OpenFlow | | | | OpenFlow | | |
||OpenFlow||<....>| | ------------ | | ------------ | |
|----------| | | NE | | NE | |
| | | +--------------+ +--------------+ |
| | | Data Plane |
|Management| +----------------------------------------+
+----------+
Figure 3: High level SDN ONF architecture
Figure 3 shows the blocks and the functional interfaces of the ONF
architecture, which comprises three planes: Data, Controller, and
Application. The Data plane comprehends several Network Entities
(NE), which expose their capabilities toward the Controller plane via
a Southbound API. The Controller plane includes several cooperating
modules devoted to the creation and maintenance of an abstracted
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resource model of the underneath network. Such model is exposed to
the applications via a Northbound API where the Application plane
comprises several applications/services, each of which has exclusive
control of a set of exposed resources.
The Management plane spans its functionality across all planes
performing the initial configuration of the network elements in the
Data plane, the assignment of the SDN controller and the resources
under its responsibility. In the Controller plane, the Management
needs to configure the policies defining the scope of the control
given to the SDN applications, to monitor the performance of the
system, and to configure the parameters required by the SDN
controller modules. In the Application plane, Management configures
the parameters of the applications and the service level agreements.
In addition to the these interactions, the Management plane exposes
several functions to network operators which can easily and quickly
configure and tune the network at each layer.
3.3. Mobile Edge Computing
Mobile Edge Computing capabilities deployed in the edge of the mobile
network can facilitate the efficient and dynamic provision of
services to mobile users. The ETSI ISG MEC working group, operative
from end of 2014, intends to specify an open environment for
integrating MEC capabilities with service providers networks,
including also applications from 3rd parties. These computing
capabilities will make available IT infrastructure for the deployment
of functions in mobile access networks. It can be seen then as a
complement to both NFV and SDN.
4. Network Virtualization at IETF/IRTF
4.1. SFC WG
Current network services deployed by operators often involve the
composition of several individual functions (such as packet
filtering, deep packet inspection, load balancing). These services
are typically implemented by the ordered combination of a number of
service functions that are deployed at different points within a
network, not necessary on the direct data path. This requires
traffic to be steered through the required service functions,
wherever they are deployed.
For a given service, the abstracted view of the required service
functions and the order in which they are to be applied is called a
Service Function Chain (SFC), which is called Network Function
Forwarding Graph (NF-FG) in ETSI. An SFC is instantiated through
selection of specific service function instances on specific network
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nodes to form a service graph: this is called a Service Function Path
(SFP). The service functions may be applied at any layer within the
network protocol stack (network layer, transport layer, application
layer, etc.).
The SFC working group is working on an architecture for service
function chaining that includes the necessary protocols or protocol
extensions to convey the Service Function Chain and Service Function
Path information to nodes that are involved in the implementation of
service functions and Service Function Chains, as well as mechanisms
for steering traffic through service functions.
In terms of actual work items, the SFC WG is chartered to deliver:
(i) a problem statement document [RFC7498], (ii) an architecture
document [I-D.ietf-sfc-architecture], (iii) a service-level data
plane encapsulation format (the encapsulation should indicate the
sequence of service functions that make up the Service Function
Chain, specify the Service Function Path, and communicate context
information between nodes that implement service functions and
Service Function Chains), and (iv) a document describing requirements
for conveying information between control or management elements and
SFC implementation points.
Potential gap: as stated in the SFC charter, any work on the
management and configuration of SFC components related to the support
of Service Function Chaining will not be done yet, until better
understood and scoped. This part is of special interest for
operators and would be required in order to actually put SFC
mechanisms into operation.
Potential gap: redundancy and reliability mechanisms are currently
not dealt with by any WG in the IETF. While this has been the main
goal of the VNFpool BoF efforts, it still remains un-addressed.
4.2. NVO3 WG
The Network Virtualization Overlays (NVO3) WG is developing protocols
that enable network virtualization overlays within large Data Center
(DC) environments. Specifically NVO3 assumes an underlying physical
Layer 3 (IP) fabric on which multiple tenant networks are virtualized
on top (i.e. overlays). With overlays, data traffic between tenants
is tunneled across the underlying DC's IP network. The use of
tunnels provides a number of benefits by decoupling the network as
viewed by tenants from the underlying physical network across which
they communicate [I-D.ietf-nvo3-arch].
Potential gap: It would be worthwhile to see if some of the specific
approaches developed in this WG (e.g. overlays, traffic isolation, VM
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migration) can be applied outside the DC, and specifically if they
can be applicable to mobile network virtualization (NFV). These
approaches would be most relevant to the ETSI Network Function
Virtualization Infrastructure (NFVI), and the Virtualized
Infrastructure Manager part of the MANO.
4.3. DMM WG
The Distributed Mobility Management (DMM) WG is looking at solutions
for IP networks that enable traffic between mobile and correspondent
nodes taking an optimal route, preventing some of the issues caused
by the use of centralized mobility solutions, which anchor all the
traffic at a given node (or a very limited set of nodes). The DMM WG
is considering the latest developments in mobile networking research
and operational practices (i.e., flattening network architectures,
the impact of virtualization, new deployment needs as wireless access
technologies evolve in the coming years) and aims at describing how
distributed mobility management addresses the new needs in this area
better than previously standardized solutions.
Although network virtualization is not the main area of the DMM work,
the impact of SDN and NFV mechanisms is clear on the work that is
currently being done in the WG. One example is architecture defined
for the virtual Evolved Packet Core (vEPC) in
[I-D.matsushima-stateless-uplane-vepc]. Here, the authors describe a
particular realization of the vEPC concept, which is designed to
support NFV. In the defined architecture, the user plane of EPC is
decoupled from the control-plane and uses routing information to
forward packets of mobile nodes. This proposal does not modify the
signaling of the EPC control plane, although the EPC control plane
runs on an hypervisor.
Potential gap: in a vEPC/DMM context, how to run the EPC control
plane on NFV.
The DMM WG is also looking at ways to supporting the separation of
the Control-Plane for mobility- and session management from the
actual Data-Plane [I-D.ietf-dmm-fpc-cpdp]. The protocol semantics
being defined abstract from the actual details for the configuration
of Data-Plane nodes and apply between a Client function, which is
used by an application of the mobility Control-Plane, and an Agent
function, which is associated with the configuration of Data-Plane
nodes according to the policies issued by the mobility Control-Plane.
Potential gap: the actual mappings between these generic protocol
semantics and the configuration commands required on the data plane
network elements are not in the scope of this document, and are
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therefore a potential gap that will need to be addressed (e.g., for
OpenFlow switches).
4.4. I2RS WG
The Interface to the Routing System (I2RS) WG is developing a high-
level architecture that describes the basic building-blocks to access
the routing system through a set of protocol-based control or
management interfaces. This architecture, as described in
[I-D.ietf-i2rs-architecture], comprises an I2RS Agent as a unified
interface that is accessed by I2RS clients using the I2RS protocol.
The client is controlled by one or more network applications and
accesses one or more agents, as shown in the following figure:
****************** ***************** *****************
* Application C * * Application D * * Application E *
****************** ***************** *****************
| | |
+--------------+ | +-------------+
| | |
***************
* Client P *----------------------+
*************** |
*********************** | |
* Application A * | |
* * | *********************** |
* +----------------+ * | * Application B * |
* | Client A | * | * * |
* +----------------+ * | * +----------------+ * |
*********************** | * | Client B | * |
| | * +----------------+ * |
| +----------------+ *********************** |
| | | | |
| | +------------------------+ | +-----+
| | | | |
******************************* *******************************
* * * *
* Routing Element 1 * * Routing Element 2 *
* * * *
******************************* *******************************
Figure 4: High level I2RS architecture
Routing elements consist of an agent that communicates with the
client or clients driven by the applications and accesses the
different subsystems in the element as shown in the following figure:
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|
*****************v**************
* +---------------------+ *
* | Agent | *
* +---------------------+ *
* ^ ^ ^ ^ *
* | | | | *
* | | | +--+ *
* | | | | *
* v | | v *
* +---+-----+ | | +----+---+ *
* | Routing | | | | Local | *
* | and | | | | Config | *
* |Signaling| | | +--------+ *
* +---------+ | | ^ *
* ^ | | | *
* | +----+ | | *
* v v v v *
* +----------+ +------------+ *
* | Dynamic | | Static | *
* | System | | System | *
* | State | | State | *
* +----------+ +------------+ *
* *
* Routing Element *
********************************
Figure 5: Architecture of a routing element
The I2RS architecture proposes to use model-driven APIs. Services
can correspond to different data-models and agents can indicate which
model they support.
Potential gap: network virtualization is not the main aim of the I2RS
WG. However, they provide an infrastructure that can be part of an
SDN deployment.
4.5. BESS WG
BGP is already used as a protocol for provisioning and operating
Layer-3 (routed) Virtual Private Networks (L3VPNs). The BGP Enabled
Services (BESS) working group is responsible for defining,
specifying, and extending network services based on BGP. In
particular, the working group will work on the following services:
o BGP-enabled VPN solutions for use in the data center networking.
This work includes consideration of VPN scaling issues and
mechanisms applicable to such environments.
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o Extensions to BGP-enabled VPN solutions for the construction of
virtual topologies in support of services such as Service Function
Chaining.
Potential gap: The most relevant activity in BESS that would be
worthwhile to investigate for relevance to mobile network
virtualization (NFV) is the extensions to BGP-enabled VPN solutions
to support of Service Function Chaining
[I-D.rfernando-bess-service-chaining].
4.6. VNFpool BoF
The VNFPOOL BoF is working on the way to group Virtual Network
Function (VNF) into pools to improve resilience, provide better
scale-out and scale-in characteristics, implement stateful failover
among VNF members of a pool, etc. Additionally, they propose to
create VNF sets from VNF pools. For this, the BoF proposes to study
signaling (both between members of a pool and across pools), state
sharing mechanisms between members of a VNFPOOL, the exchange of
reliability information between VNF sets, their users and the
underlying network, and the reliability and security of the control
plane needed to transport the exchanged information.
The VNFPOOL BoF started work on the charter, use case study, and
requirements and initial architecture. The use cases include Content
Deliver Networks (CDNs), the LTE mobile core network and reliable
server pooling. Currently, there is no activity on the mailing list
setup for this activity.
Potential gap: VNFPOOL tries to introduce and manage resilience in
virtualized networking environments and therefore addresses a
desirable feature for any software defined network. VNFPOOL has also
been integrated into the NFV architecture
[I-D.bernini-nfvrg-vnf-orchestration].
4.7. TEAS WG
Transport network infrastructure provides end-to-end connectivity for
networked applications and services. Network virtualization
facilitates effective sharing (or 'slicing') of physical
infrastructure by representing resources and topologies via
abstractions, even in a multi-administration, multi-vendor, multi-
technology environment. In this way, it becomes possible to operate,
control and manage multiple physical networks elements as single
virtualized network. The users of such virtualized network can
control the allocated resources in an optimal and flexible way,
better adapting to the specific circumstances of higher layer
applications.
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Abstraction and Control of Transport Networks (ACTN) intends to
define methods and capabilities for the deployment and operation of
transport network resources [I-D.ceccarelli-teas-actn-framework].
This activity is currently being carried out within the Traffic
Engineering Architecture and Signaling (TEAS) WG.
Several use cases are being proposed for both fixed and mobile
scenarios [I-D.leeking-teas-actn-problem-statement].
Potential gap: Several use cases in ACTN are relevant to mobile
network virtualization (NFV). Control of multi-tenant mobile
backhaul transport networks, mobile virtual network operation, etc,
can be influenced by the location of the network functions. A
control architecture allowing for inter-operation of NFV and
transport network (e.g., for combined optimization) is one relevant
area for research.
4.8. NFV RG
The NFVRG focuses on research problems associated with virtualization
of fixed and mobile network infrastructures, new network
architectures based on virtualized network functions, virtualization
of the home and enterprise network environments, co-existence with
non-virtualized infrastructure and services, and application to
growing areas of concern such as Internet of Things (IoT) and next
generation content distribution. Another goal of the NFVRG is to
bring a research community together that can jointly address such
problems, concentrating on problems that relate not just to
networking but also to computing and storage constraints in such
environments.
Since the NFVRG is a research group, it has a wide scope. In order
to keep the focus, the group has identified some near term work
items: (i) Policy based Resource Management, (ii) Analytics for
Visibility and Orchestration, (iii) Virtual Network Function (VNF)
Performance Modelling to facilitate transition to NFV and (iv)
Security and Service Verification.
4.9. SDN RG
The SDNRG provides the grounds for an open-minded investigation of
Software Defined Networking. They aim at identifying approaches that
can be defined and used in the near term as well as the research
challenges in the field. As such, they SDNRG will not define
standards, but provide inputs to standards defining and standards
producing organizations.
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It is working on classifying SDN models, including definitions and
taxonomies. It is also studying complexity, scalability and
applicability of the SDN model. Additionally, the SDNRG is working
on network description languages (and associated tools), abstractions
and interfaces. They also investigate the verification of correct
operation of network or node function.
The SDNRG has produced a reference layer model RFC7426 [RFC7426],
which structures SDNs in planes and layers which are glued together
by different abstraction layers. This architecture differentiates
between the control and the management planes and provides for
differentiated southbound interfaces (SBIs).
5. Summary of Gaps
Potential Gap-1: as stated in the SFC charter, any work on the
management and configuration of SFC components related to the support
of Service Function Chaining will not be done yet, until better
understood and scoped. This part is of special interest for
operators and would be required in order to actually put SFC
mechanisms into operation.
Potential Gap-2: redundancy and reliability mechanisms are currently
not dealt with by SFC or any other WG in the IETF. While this has
been the main goal of the VNFpool BoF efforts, it still remains un-
addressed.
Potential Gap-3: it would be worthwhile to see if some of the
specific approaches developed in the NVO3 WG (e.g. overlays, traffic
isolation, VM migration) can be applied outside the DC, and
specifically if they can be applicable to mobile network
virtualization (NFV). These approaches would be most relevant to the
ETSI Network Function Virtualization Infrastructure (NFVI), and the
Virtualized Infrastructure Manager part of the MANO.
Potential Gap-4: the most relevant activity in BESS that would be
worthwhile to investigate for relevance to mobile network
virtualization (NFV) is the extensions to BGP-enabled VPN solutions
to support of Service Function Chaining.
Potential Gap-5: in a vEPC/DMM context, how to run the EPC control
plane on NFV.
Potential Gap-6: in DMM, on the work item addressing the separation
of the Control-Plane for mobility- and session management from the
actual Data-Plane, the actual mappings between these generic protocol
semantics and the configuration commands required on the data plane
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network elements (e.g., OpenFlow switches) are not currently in the
scope of the DMM WG.
Potential Gap-7: network virtualization is not the main aim of the
I2RS WG. However, they provide an infrastructure that can be part of
an SDN deployment.
Potential Gap-8: the most relevant activity in BESS that would be
worthwhile to investigate for relevance to mobile network
virtualization (NFV) is the extensions to BGP-enabled VPN solutions
to support of Service Function Chaining.
Potential Gap-9: VNFPOOL tries to introduce and manage resilience in
virtualized networking environments and therefore addresses a
desirable feature for any software defined network. VNFPOOL has also
been integrated into the NFV architecture
[I-D.bernini-nfvrg-vnf-orchestration].
Potential Gap-10: several use cases in ACTN are relevant to mobile
network virtualization (NFV). Control of multi-tenant mobile
backhaul transport networks, mobile virtual network operation, etc,
can be influenced by the location of the network functions. A
control architecture allowing for inter-operation of NFV and
transport network (e.g., for combined optimization) is one relevant
area for research.
6. IANA Considerations
N/A.
7. Security Considerations
TBD.
8. Acknowledgments
The work of Pedro Aranda is supported by the European FP7 Project
Trilogy2 under grant agreement 317756.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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9.2. Informative References
[I-D.bernini-nfvrg-vnf-orchestration]
Bernini, G., Maffione, V., Lopez, D., and P. Aranda, "VNF
Orchestration For Automated Resiliency in Service Chains",
draft-bernini-nfvrg-vnf-orchestration-00 (work in
progress), July 2015.
[I-D.ceccarelli-teas-actn-framework]
Ceccarelli, D. and Y. Lee, "Framework for Abstraction and
Control of Transport Networks", draft-ceccarelli-teas-
actn-framework-00 (work in progress), June 2015.
[I-D.ietf-dmm-fpc-cpdp]
Liebsch, M., Matsushima, S., Gundavelli, S., and D. Moses,
"Protocol for Forwarding Policy Configuration (FPC) in
DMM", draft-ietf-dmm-fpc-cpdp-00 (work in progress), May
2015.
[I-D.ietf-i2rs-architecture]
Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
Nadeau, "An Architecture for the Interface to the Routing
System", draft-ietf-i2rs-architecture-09 (work in
progress), March 2015.
[I-D.ietf-nvo3-arch]
Black, D., Hudson, J., Kreeger, L., Lasserre, M., and T.
Narten, "An Architecture for Overlay Networks (NVO3)",
draft-ietf-nvo3-arch-03 (work in progress), March 2015.
[I-D.ietf-sfc-architecture]
Halpern, J. and C. Pignataro, "Service Function Chaining
(SFC) Architecture", draft-ietf-sfc-architecture-09 (work
in progress), June 2015.
[I-D.leeking-teas-actn-problem-statement]
Lee, Y., King, D., Boucadair, M., Jing, R., and L.
Contreras, "Problem Statement for Abstraction and Control
of Transport Networks", draft-leeking-teas-actn-problem-
statement-00 (work in progress), June 2015.
[I-D.matsushima-stateless-uplane-vepc]
Matsushima, S. and R. Wakikawa, "Stateless user-plane
architecture for virtualized EPC (vEPC)", draft-
matsushima-stateless-uplane-vepc-04 (work in progress),
March 2015.
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[I-D.rfernando-bess-service-chaining]
Fernando, R., Rao, D., Fang, L., Napierala, M., So, N.,
and A. Farrel, "Virtual Topologies for Service Chaining in
BGP/IP MPLS VPNs", draft-rfernando-bess-service-
chaining-01 (work in progress), April 2015.
[RFC7426] Haleplidis, E., Pentikousis, K., Denazis, S., Hadi Salim,
J., Meyer, D., and O. Koufopavlou, "Software-Defined
Networking (SDN): Layers and Architecture Terminology",
RFC 7426, January 2015.
[RFC7498] Quinn, P. and T. Nadeau, "Problem Statement for Service
Function Chaining", RFC 7498, April 2015.
Appendix A. The mobile network use case
A.1. The 3GPP Evolved Packet System
TBD. This will include a high level summary of the 3GPP EPS
architecture, detailing both the EPC (core) and the RAN (access)
parts. A link with the two related ETSI NFV use cases
(Virtualisation of Mobile Core Network and IMS, and Virtualisation of
Mobile base station) will be included.
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+---------------------------------------------------------+
| PCRF |
+-----------+--------------------------+----------------+-+
| | |
+----+ +-----------+------------+ +--------+-----------+ +-+-+
| | | +-+ | | Core Network | | |
| | | +------+ |S|__ | | +--------+ +---+ | | |
| | | |GERAN/|_|G| \ | | | HSS | | | | | |
| +-----+ UTRAN| |S| \ | | +---+----+ | | | | E |
| | | +------+ |N| +-+-+ | | | | | | | x |
| | | +-+ /|MME| | | +---+----+ | | | | t |
| | | +---------+ / +---+ | | | 3GPP | | | | | e |
| +-----+ E-UTRAN |/ | | | AAA | | | | | r |
| | | +---------+\ | | | SERVER | | | | | n |
| | | \ +---+ | | +--------+ | | | | a |
| | | 3GPP AN \|SGW+----- S5---------------+ P | | | l |
| | | +---+ | | | G | | | |
| | +------------------------+ | | W | | | I |
| UE | | | | | | P |
| | +------------------------+ | | +-----+ |
| | |+-------------+ +------+| | | | | | n |
| | || Untrusted +-+ ePDG +-S2b---------------+ | | | e |
| +---+| non-3GPP AN | +------+| | | | | | t |
| | |+-------------+ | | | | | | w |
| | +------------------------+ | | | | | o |
| | | | | | | r |
| | +------------------------+ | | | | | k |
| +---+ Trusted non-3GPP AN +-S2a--------------+ | | | s |
| | +------------------------+ | | | | | |
| | | +-+-+ | | |
| +--------------------------S2c--------------------| | | |
| | | | | |
+----+ +--------------------+ +---+
Figure 6: EPS (non-roaming) architecture overview
A.2. Virtualizing the 3GPP EPS
TBD. We describe how a "virtual EPS" (vEPS) would look like and the
existing gaps that exist from the point of view of network
virtualization.
Authors' Addresses
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Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/
Akbar Rahman
InterDigital Communications, LLC
1000 Sherbrooke Street West, 10th floor
Montreal, Quebec H3A 3G4
Canada
Email: Akbar.Rahman@InterDigital.com
URI: http://www.InterDigital.com/
Juan Carlos Zuniga
InterDigital Communications, LLC
1000 Sherbrooke Street West, 10th floor
Montreal, Quebec H3A 3G4
Canada
Email: JuanCarlos.Zuniga@InterDigital.com
URI: http://www.InterDigital.com/
Luis M. Contreras
Telefonica I+D
Ronda de la Comunicacion, S/N
Madrid 28050
Spain
Email: luismiguel.conterasmurillo@telefonica.com
Pedro Aranda
Telefonica I+D
Ronda de la Comunicacion, S/N
Madrid 28050
Spain
Email: pedroa.aranda@telefonica.com
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