Internet DRAFT - draft-bernardos-nfvrg-gaps-network-virtualization
draft-bernardos-nfvrg-gaps-network-virtualization
NFVRG CJ. Bernardos
Internet-Draft UC3M
Intended status: Informational A. Rahman
Expires: September 22, 2016 JC. Zuniga
InterDigital
LM. Contreras
P. Aranda
TID
March 21, 2016
Gap Analysis on Network Virtualization Activities
draft-bernardos-nfvrg-gaps-network-virtualization-04
Abstract
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, automation and
orchestration, putting them into context considering efforts by other
SDOs, and identifying current gaps and challenges that can be tackled
at IETF or researched at the IRTF.
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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This Internet-Draft will expire on September 22, 2016.
Copyright Notice
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Network Function Virtualization . . . . . . . . . . . . . 5
3.2. Software Defined Networking . . . . . . . . . . . . . . . 7
3.3. Mobile Edge Computing . . . . . . . . . . . . . . . . . . 11
3.4. IEEE 802.1CF (OmniRAN) . . . . . . . . . . . . . . . . . 12
3.5. Distributed Management Task Force . . . . . . . . . . . . 12
3.6. Open Source initiatives . . . . . . . . . . . . . . . . . 12
4. Network Virtualization at IETF/IRTF . . . . . . . . . . . . . 14
4.1. SDN RG . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2. SFC WG . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.3. NVO3 WG . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4. DMM WG . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.5. I2RS WG . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.6. BESS WG . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.7. BM WG . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.8. TEAS WG . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.9. I2NSF WG . . . . . . . . . . . . . . . . . . . . . . . . 20
4.10. IPPM WG . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.11. NFV RG . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.12. VNFpool BoF . . . . . . . . . . . . . . . . . . . . . . . 22
5. Summary of Gaps . . . . . . . . . . . . . . . . . . . . . . . 23
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
7. Security Considerations . . . . . . . . . . . . . . . . . . . 25
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25
9. Informative References . . . . . . . . . . . . . . . . . . . 25
Appendix A. The mobile network use case . . . . . . . . . . . . 28
A.1. The 3GPP Evolved Packet System . . . . . . . . . . . . . 28
A.2. Virtualizing the 3GPP EPS . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
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
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demand, some network operators are looking at the cloud computing
paradigm, which enables a potential 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
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.
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2. Terminology
The following terms used in this document are defined by the ETSI NVF
ISG, the ONF and the IETF:
Application Plane - The collection of applications and services
that program network behavior.
Control Plane (CP) - The collection of functions responsible for
controlling one or more network devices. CP instructs network
devices with respect to how to process and forward packets. The
control plane interacts primarily with the forwarding plane and,
to a lesser extent, with the operational plane.
Forwarding Plane (FP) - The collection of resources across all
network devices responsible for forwarding traffic.
Management Plane (MP) - The collection of functions responsible
for monitoring, configuring, and maintaining one or more network
devices or parts of network devices. The management plane is
mostly related to the operational plane (it is related less to the
forwarding plane).
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): allowing vendor independent programming
of control functions in network nodes.
Operational Plane (OP) - The collection of resources responsible
for managing the overall operation of individual network devices.
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.
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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): control plane of 3GPPs EPC operated on NFV
framework (as defined by [I-D.matsushima-stateless-uplane-vepc]).
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 [etsi_nvf_whitepaper]. 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: https://www.opennetworking.org/). 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.
The SDNRG has documented a reference layer model in RFC7426
[RFC7426], which is reproduced in Figure 4. This model structures
SDN 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).
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o--------------------------------o
| |
| +-------------+ +----------+ |
| | Application | | Service | |
| +-------------+ +----------+ |
| Application Plane |
o---------------Y----------------o
|
*-----------------------------Y---------------------------------*
| Network Services Abstraction Layer (NSAL) |
*------Y------------------------------------------------Y-------*
| |
| Service Interface |
| |
o------Y------------------o o---------------------Y------o
| | Control Plane | | Management Plane | |
| +----Y----+ +-----+ | | +-----+ +----Y----+ |
| | Service | | App | | | | App | | Service | |
| +----Y----+ +--Y--+ | | +--Y--+ +----Y----+ |
| | | | | | | |
| *----Y-----------Y----* | | *---Y---------------Y----* |
| | Control Abstraction | | | | Management Abstraction | |
| | Layer (CAL) | | | | Layer (MAL) | |
| *----------Y----------* | | *----------Y-------------* |
| | | | | |
o------------|------------o o------------|---------------o
| |
| CP | MP
| Southbound | Southbound
| Interface | Interface
| |
*------------Y---------------------------------Y----------------*
| Device and resource Abstraction Layer (DAL) |
*------------Y---------------------------------Y----------------*
| | | |
| o-------Y----------o +-----+ o--------Y----------o |
| | Forwarding Plane | | App | | Operational Plane | |
| o------------------o +-----+ o-------------------o |
| Network Device |
+---------------------------------------------------------------+
Figure 4: SDN Layer Architecture
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
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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 distributed
computing capabilities will make available IT infrastructure as in a
cloud environment for the deployment of functions in mobile access
networks. It can be seen then as a complement to both NFV and SDN.
3.4. IEEE 802.1CF (OmniRAN)
The IEEE 802.1CF Recommended Practice specifies an access network,
which connects terminals to their access routers, utilizing
technologies based on the family of IEEE 802 Standards (e.g., 802.3
Ethernet, 802.11 Wi-Fi, etc.). The specification defines an access
network reference model, including entities and reference points
along with behavioral and functional descriptions of communications
among those entities.
The goal of this project is to help unifying the support of different
interfaces, enabling shared network control and use of software
defined network (SDN) principles, thereby lowering the barriers to
new network technologies, to new network operators, and to new
service providers.
3.5. Distributed Management Task Force
The DMTF is an industry standards organization working to simplify
the manageability of network-accessible technologies through open and
collaborative efforts by some technology companies. The DMTF is
involved in the creation and adoption of interoperable management
standards, supporting implementations that enable the management of
diverse traditional and emerging technologies including cloud,
virtualization, network and infrastructure.
There are several DMTF initiatives that are relevant to the network
virtualization area, such as the Open Virtualization Format (OVF),
for VNF packaging; the Cloud Infrastructure Management Interface
(CIM), for cloud infrastructure management; the Network Management
(NETMAN), for VNF management; and, the Virtualization Management
(VMAN), for virtualization infrastructure management.
3.6. Open Source initiatives
The Open Source community is especially active in the area of network
virtualization. We next summarize some of the active efforts:
o OpenStack. OpenStack is a free and open-source cloud-computing
software platform. OpenStack software controls large pools of
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compute, storage, and networking resources throughout a
datacenter, managed through a dashboard or via the OpenStack API.
o OpenDayLight. OpenDaylight (ODL) is a highly available, modular,
extensible, scalable and multi-protocol controller infrastructure
built for SDN deployments on modern heterogeneous multi-vendor
networks. It provides a model-driven service abstraction platform
that allows users to write apps that easily work across a wide
variety of hardware and southbound protocols.
o ONOS. The ONOS (Open Network Operating System) project is an open
source community hosted by The Linux Foundation. The goal of the
project is to create a software-defined networking (SDN) operating
system for communications service providers that is designed for
scalability, high performance and high availability.
o OpenContrail. OpenContrail is an Apache 2.0-licensed project that
is built using standards-based protocols and provides all the
necessary components for network virtualization-SDN controller,
virtual router, analytics engine, and published northbound APIs.
It has an extensive REST API to configure and gather operational
and analytics data from the system.
o OPNFV. OPNFV is a carrier-grade, integrated, open source platform
to accelerate the introduction of new NFV products and services.
By integrating components from upstream projects, the OPNFV
community aims at conducting performance and use case-based
testing to ensure the platform's suitability for NFV use cases.
The scope of OPNFV's initial release is focused on building NFV
Infrastructure (NFVI) and Virtualized Infrastructure Management
(VIM) by integrating components from upstream projects such as
OpenDaylight, OpenStack, Ceph Storage, KVM, Open vSwitch, and
Linux. These components, along with application programmable
interfaces (APIs) to other NFV elements form the basic
infrastructure required for Virtualized Network Functions (VNF)
and Management and Network Orchestration (MANO) components.
OPNFV's goal is to increase performance and power efficiency;
improve reliability, availability, and serviceability; and deliver
comprehensive platform instrumentation.
o OSM. Open Source Mano (OSM) is an ETSI-hosted project to develop
an Open Source NFV Management and Orchestration (MANO) software
stack aligned with ETSI NFV. OSM is based on components from
previous projects, such Telefonica's OpenMANO or Canonical's Juju,
among others.
o OpenBaton. OpenBaton is a ETSI NFV compliant Network Function
Virtualization Orchestrator (NFVO). OpenBaton was part of the
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OpenSDNCore project started with the objective of providing a
compliant implementation of the ETSI NFV specification.
Among the main areas that are being developed by the former open
source activities that related to network virtualization research, we
can highlight: policy-based resource management, analytics for
visibility and orchestration, service verification with regards to
security and resiliency.
4. Network Virtualization at IETF/IRTF
4.1. 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.
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).
4.2. 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
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selection of specific service function instances on specific network
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 [RFC7665], (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.
4.3. 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 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.
4.4. 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).
4.5. 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 5: 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 6: 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.
4.6. 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 network virtualization
(NFV) is the extensions to BGP-enabled VPN solutions to support of
Service Function Chaining [I-D.rfernando-bess-service-chaining].
4.7. BM WG
The Benchmarking Methodology Working Group (BMWG) provides
recommendations concerning the key performance characteristics of
internetworking technologies, or benchmarks for network devices,
systems, and services. The scope of BMWG includes benchmarks for the
management, control, and forwarding planes, and is.
The main distinguishing characteristic of BMWG from other IETF
measurement initiatives like the IPPM WG is that BMWG is limited to
characterization of implementations using controlled stimuli in a lab
environment. The BMWG does not attempt to produce benchmarks for
live, operational networks.
As part of the tasks of the BMWG, it is explicitly tasked to develop
benchmarks and methodologies for VNF and related infrastructure
benchmarking, Benchmarking Methodologies have reliably characterized
many physical devices. This work item extends and enhances the
methods to virtual network functions (VNF) and their unique
supporting infrastructure. The first deliverable from this activity
mentioned in the charter of the WG is a document
[I-D.ietf-bmwg-virtual-net] that considers the new benchmarking space
to ensure that common issues are recognized from the start, using
background materials from industry and SDOs (e.g., IETF, ETSI NFV).
This document investigates the additional methodological
considerations necessary when benchmarking VNFs instantiated and
hosted in general-purpose hardware. The approach is to benchmark
physical and virtual network functions in the same way when possible,
thereby allowing direct comparison. Also defining benchmarking
combinations of physical and virtual devices in a System Under Test.
Benchmarks for platform capacity and performance characteristics of
virtual routers, switches, and related components will be also
addressed, including comparisons between physical and virtual network
functions. In many cases, the traditional benchmarks should be
applicable to VNFs, but the lab set-ups, configurations, and
measurement methods will likely need to be revised or enhanced.
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There are additional documents of the BMWG relevant to the
virtualization area, such as:
[I-D.ietf-bmwg-sdn-controller-benchmark-term],
[I-D.ietf-bmwg-sdn-controller-benchmark-meth], [I-D.kim-bmwg-ha-nfvi]
and [I-D.vsperf-bmwg-vswitch-opnfv].
4.8. 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.
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 network
virtualization (NFV) in mobile environments. 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.
4.9. I2NSF WG
The I2NSF WG at defining interfaces to the flow based network
security functions (NSFs) hosted by service providers at different
premises. Network Security Function (NSF) is to ensure integrity,
confidentiality and availability of network communications, to detect
unwanted activity, and to block it or at least mitigate its effects.
NSFs are provided and consumed in increasingly diverse environments.
Users of NSFs could consume network security services hosted by one
or more providers, which may be their own enterprise, service
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providers, or a combination of both. The NSFs may be provided by
physical and/or virtualized infrastructure.
Without standard interfaces to express, monitor, and control security
policies that govern the behavior of NSFs, it becomes virtually
impossible for security service providers to automate their service
offerings that utilize different security functions from multiple
vendors. Based on this, the main goal of I2NSF is to define an
information model, a set of software interfaces and data models for
controlling and monitoring aspects of NSFs (both physical and
virtual) [I-D.jeong-i2nsf-sdn-security-services].
Since different security vendors may support different features and
functions on their devices, I2NSF focuses on flow based NSFs that
provide treatment to packets/flow.
The I2NSF WG's target deliverables include: (i) a use cases, problem
statement, gap analysis document, (ii) a framework document,
presenting an overview of the use of NSFs and the purpose of the
models developed by the WG, (iii) a single, unified, Information
Model for controlling and monitoring flow-based NSFs, (iv) the
corresponding YANG Data Models derived from the Information Model,
(v) a vendor-neutral vocabulary to enable the characteristics and
behavior of NSFs to be specified without requiring the NSFs
themselves to be standardized, and (vi) an examination of existing
secure communication mechanisms to identify the appropriate ones for
carrying the controlling and monitoring information between the NSFs
and their management entities. The WG is also targeted to work
closely with I2RS, Netconf and Netmod WGs, as well as to communicate
with external SDOs like ETSI NFV.
Potential gap: aspects of NSFs such as device or network provisioning
and configuration are out of scope.
Potential gap: the use of SDN tools to interact with security
functions is not explictly considered, but seems a potential
approach, as for example described for the particular case of IPsec
flow protection in [I-D.abad-sdnrg-sdn-ipsec-flow-protection].
4.10. IPPM WG
The IP Performance Metrics (IPPM) WG defines metrics that can be used
to measure the quality and performance of Internet services and
applications running over transport layer protocols (e.g. TCP, UPD)
over IP. It also develops and maintains protocols for the
measurement of these metrics. The IPPM WG is a long running WG that
started in 1997. The architecture (framework) for IPPM WG metrics
and associated protocols are defined in RFC 2330 [RFC2330]. Some
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examples of recent output by IPPM WG include "A Reference Path and
Measurement Points for Large-Scale Measurement of Broadband
Performance" (RFC 7398 [RFC7398]) and "Framework for TCP Throughput
Testing" (RFC 6349 [RFC6349]).
The IPPM WG currently does not have a charter item or active drafts
related to the topic of network virtualization. On the automation
and orchestration side, there is an ongoing effort
[I-D.cmzrjp-ippm-twamp-yang] to define a YANG model for the IPPM
protocol.
Potential gap: There is a pressing need to define metrics and
associated protocols to measure the performance of NFV.
Specifically, since NFV is based on the concept of taking centralized
functions and evolving it to highly distributed SW functions, there
is a commensurate need to fully understand and measure the baseline
performance of such systems. A potential topic for the IPPM WG is
defining packet delay, throughput, and test framework for the
application traffic flowing through the NFVI.
4.11. 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.
4.12. VNFpool BoF
The VNFPOOL BoF proposed to work 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 proposed to study
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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 use cases initially considered by VNFPOOL include Content Deliver
Networks (CDNs), the LTE mobile core network and reliable server
pooling. The VNFPOOL work has been dropped in the IETF.
Potential gap: VNFPOOL tried 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].
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, since VNFPOOL work has
been dropped for the time being without any WG being chartered, the
technical topics it aimed at targetting still remain 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 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 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.
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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
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: 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-9: within the Traffic Engineering Architecture and
Signaling (TEAS) WG, several use cases in ACTN are relevant to
network virtualization (NFV) in mobile environments. 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.
Potential Gap-10: within I2NSF', aspects of NSFs such as device or
network provisioning and configuration are out of scope.
Potential Gap-11: the use of SDN tools to interact with security
functions is not explictly considered in I2NSF, but seems a potential
approach, as for example described for the particular case of IPsec
flow protection in [I-D.abad-sdnrg-sdn-ipsec-flow-protection].
Potential Gap-12: there is a pressing need to define metrics and
associated protocols to measure the performance of NFV.
Specifically, since NFV is based on the concept of taking centralized
functions and evolving it to highly distributed SW functions, there
is a commensurate need to fully understand and measure the baseline
performance of such systems. A potential topic for the IPPM WG is
defining packet delay, throughput, and test framework for the
application traffic flowing through the NFVI.
6. IANA Considerations
N/A.
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7. Security Considerations
TBD.
8. Acknowledgments
The authors want to thank Dirk von Hugo, Rafa Marin, Diego Lopez,
Ramki Krishnan, Kostas Pentikousis, Rana Pratap Sircar and Alfred
Morton for their very useful reviews and comments to the document.
The work of Pedro Aranda is supported by the European FP7 Project
Trilogy2 under grant agreement 317756.
9. Informative References
[etsi_nvf_whitepaper]
"Network Functions Virtualisation (NFV). White Paper 2",
October 2014.
[I-D.abad-sdnrg-sdn-ipsec-flow-protection]
Abad-Carrascosa, A., Lopez, R., and G. Lopez-Millan,
"Software-Defined Networking (SDN)-based IPsec Flow
Protection", draft-abad-sdnrg-sdn-ipsec-flow-protection-01
(work in progress), October 2015.
[I-D.bernini-nfvrg-vnf-orchestration]
Bernini, G., Maffione, V., Lopez, D., and P. Aranda, "VNF
Pool Orchestration For Automated Resiliency in Service
Chains", draft-bernini-nfvrg-vnf-orchestration-01 (work in
progress), October 2015.
[I-D.ceccarelli-teas-actn-framework]
Ceccarelli, D. and Y. Lee, "Framework for Abstraction and
Control of Traffic Engineered Networks", draft-ceccarelli-
teas-actn-framework-01 (work in progress), March 2016.
[I-D.cmzrjp-ippm-twamp-yang]
Civil, R., Morton, A., Zheng, L., Rahman, R.,
Jethanandani, M., and K. Pentikousis, "Two-Way Active
Measurement Protocol (TWAMP) Data Model", draft-cmzrjp-
ippm-twamp-yang-02 (work in progress), October 2015.
[I-D.ietf-bmwg-sdn-controller-benchmark-meth]
Vengainathan, B., Basil, A., Tassinari, M., Manral, V.,
and S. Banks, "Benchmarking Methodology for SDN Controller
Performance", draft-ietf-bmwg-sdn-controller-benchmark-
meth-01 (work in progress), March 2016.
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[I-D.ietf-bmwg-sdn-controller-benchmark-term]
Vengainathan, B., Basil, A., Tassinari, M., Manral, V.,
and S. Banks, "Terminology for Benchmarking SDN Controller
Performance", draft-ietf-bmwg-sdn-controller-benchmark-
term-01 (work in progress), March 2016.
[I-D.ietf-bmwg-virtual-net]
Morton, A., "Considerations for Benchmarking Virtual
Network Functions and Their Infrastructure", draft-ietf-
bmwg-virtual-net-01 (work in progress), September 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-01 (work in progress), July
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-13 (work in
progress), February 2016.
[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-04 (work in progress), October 2015.
[I-D.jeong-i2nsf-sdn-security-services]
Jeong, J., Kim, H., Jung-Soo, P., Ahn, T., and s.
sehuilee@kt.com, "Software-Defined Networking Based
Security Services using Interface to Network Security
Functions", draft-jeong-i2nsf-sdn-security-services-04
(work in progress), March 2016.
[I-D.kim-bmwg-ha-nfvi]
Kim, T. and E. Paik, "Considerations for Benchmarking High
Availability of NFV Infrastructure", draft-kim-bmwg-ha-
nfvi-00 (work in progress), October 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.
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[I-D.matsushima-stateless-uplane-vepc]
Matsushima, S. and R. Wakikawa, "Stateless user-plane
architecture for virtualized EPC (vEPC)", draft-
matsushima-stateless-uplane-vepc-05 (work in progress),
September 2015.
[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.
[I-D.vsperf-bmwg-vswitch-opnfv]
Tahhan, M., O'Mahony, B., and A. Morton, "Benchmarking
Virtual Switches in OPNFV", draft-vsperf-bmwg-vswitch-
opnfv-01 (work in progress), October 2015.
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330,
DOI 10.17487/RFC2330, May 1998,
<http://www.rfc-editor.org/info/rfc2330>.
[RFC6349] Constantine, B., Forget, G., Geib, R., and R. Schrage,
"Framework for TCP Throughput Testing", RFC 6349,
DOI 10.17487/RFC6349, August 2011,
<http://www.rfc-editor.org/info/rfc6349>.
[RFC7398] Bagnulo, M., Burbridge, T., Crawford, S., Eardley, P., and
A. Morton, "A Reference Path and Measurement Points for
Large-Scale Measurement of Broadband Performance",
RFC 7398, DOI 10.17487/RFC7398, February 2015,
<http://www.rfc-editor.org/info/rfc7398>.
[RFC7426] Haleplidis, E., Ed., Pentikousis, K., Ed., Denazis, S.,
Hadi Salim, J., Meyer, D., and O. Koufopavlou, "Software-
Defined Networking (SDN): Layers and Architecture
Terminology", RFC 7426, DOI 10.17487/RFC7426, January
2015, <http://www.rfc-editor.org/info/rfc7426>.
[RFC7498] Quinn, P., Ed. and T. Nadeau, Ed., "Problem Statement for
Service Function Chaining", RFC 7498,
DOI 10.17487/RFC7498, April 2015,
<http://www.rfc-editor.org/info/rfc7498>.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015,
<http://www.rfc-editor.org/info/rfc7665>.
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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.
The EPS architecture and some of its standardized interfaces are
depicted in Figure 7. The EPS provides IP connectivity to user
equipment (UE) (i.e., mobile nodes) and access to operator services,
such as global Internet access and voice communications. The EPS
comprises the core network -- called Evolved Packet Core (EPC) -- and
different radio access networks: the 3GPP Access Network (AN), the
Untrusted non-3GPP AN and the Trusted non-3GPP AN. There are
different types of 3GPP ANs, with the evolved UMTS Terrestrial Radio
Access Network (E-UTRAN) as the most advanced one. QoS is supported
through an EPS bearer concept, providing bindings to resource
reservation within the network.
The evolved NodeB (eNB), the Long Term Evolution (LTE) base station,
is part of the access network that provides radio resource
management, header compression, security and connectivity to the core
network through the S1 interface. In an LTE network, the control
plane signaling traffic and the data traffic ar handled separately.
The eNBs transmit the control traffic and data traffic separately via
two logically separate interfaces.
The Home Subscriber Server, HSS, is a database that contains user
subscriptions and QoS profiles. The Mobility Management Entity, MME,
is responsible for mobility management, user authentication, bearer
establishment and modification and maintenance of the UE context.
The Serving gateway, S-GW, is the mobility anchor and manages the
user plane data tunnels during the inter-eNB handovers. It tunnels
all user data packets and buffers downlink IP packets destined for
UEs that happen to be in idle mode.
The Packet Data Network (PDN) Gateway, P-GW, is responsible for IP
address allocation to the UE and is a tunnel endpoint for user and
control plane protocols. It is also responsible for charging, packet
filtering, and policy-based control of flows. It interconnects the
mobile network to external IP networks, e.g. the Internet.
In this architecture, data packets are not sent directly on an IP
network between the eNB and the gateways. Instead, every packet is
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Internet-Draft Gap Analysis Network Virtualization March 2016
tunneled over a tunneling protocol - the GPRS Tunneling Protocol (GTP
over UDP/IP. A GTP path is identified in each node with the IP
address and a UDP port number on the eNB/gateways. The GTP protocol
carries both the data traffic (GTP-U tunnels) and the control traffic
(GTP-C tunnels). Alternatively Proxy Mobile IP (PMIPv6) is used on
the S5 interface between S-GW and P-GW.
In addition to the above basic functions and entities, there are also
additional features being discussed by the 3GPP that are relevant
from a network virtualization viewpoint. One example is the Traffic
Detection Function (TDF), which can be used by the P-GW, and in
general by the whole transport network, to decide how to forward the
traffic. In a virtualized infrastructure, this kinf of information
can be used to elastic and dynamically adapt the network capabilities
to the traffic nature and volume.
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Internet-Draft Gap Analysis Network Virtualization March 2016
+---------------------------------------------------------+
| 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 7: 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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Internet-Draft Gap Analysis Network Virtualization March 2016
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
Bernardos, et al. Expires September 22, 2016 [Page 31]
