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Versions: 00 01                                                         
SDNRG                                                         R. Gu, Ed.
Internet-Draft                                                     C. Li
Intended status: Informational                                   R. Wang
Expires: January 1, 2016                                    China Mobile
                                                           June 30, 2015


  Problem statement of SDN and NFV co-deployment in cloud datacenters
          draft-gu-sdnrg-problem-statement-of-sdn-nfv-in-dc-00

Abstract

   With the development of cloud computing technology, cloud datacenters
   have been influenced.  Co-deployment of SDN and NFV technology shows
   its distinct advantages of vitalizing network resources in providing
   VPC services and SFC services.In order to deploy SDN and NFV in cloud
   datacenters, a resolution test has been conducted.  According to the
   resolution test, SDN and NFV technology has been mature already for
   the commercial deployment in operators' network.  However, there are
   some key problems on network architecture, virtualized platform,
   standard interfaces and so on to be working out in practical
   practice.

Status of This Memo

   This Internet-Draft is submitted to IETF 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-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on January 1, 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



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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Definition of terms . . . . . . . . . . . . . . . . . . . . .   3
   4.  SDN and NFV usecase in cloud datacenters  . . . . . . . . . .   3
   5.  Resolution test of SDN and NFV in cloud datacenters . . . . .   4
   6.  Problems and aspects to be considered in the trail deployment   5
   7.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .   6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   10. Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Datacenters have been heavily impacted due to the development and
   large-scale deployment of cloud computing technology.  Co-deployment
   of SDN and NFV technology shows its distinct advantages of
   virtualizing network resources in the scenario of cloud datacenter
   such as convenient and elastic.

   SDN technology helps the cloud datacenters with central-management
   and resource efficiency.  NFV brings up virtual machines instead of
   physical firewall, load balancer, and VPN gateway devices.  Thus VPC
   services and service functions are provided with the SDN
   architecture, NFV elements, standard interfaces and the designing
   flow table.

   In order to deploy SDN and NFV in cloud datacenters, we have
   conducted a resolution test aiming at co-deployment of SDN and NFV.
   According to the resolution test, SDN and NFV technology have been
   mature already for the commercial deployment in operators' network.
   However, there are some key problems on network architecture,
   virtualized platform, standard interfaces and so on to be working out
   in practical practice.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].





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3.  Definition of terms

   NAT: network address translation

   NFV: network function virtualization

   SDN: software defined network

   SF: service function

   SFC: service function chaining

   VAS: value-added service

   VFW: virtual firewall

   VLB: virtual load balancer

   VM: virtual machine

   VPC: virtual private cloud

4.  SDN and NFV usecase in cloud datacenters

   In cloud datacenters, the SDN and NFV architecture includes the
   applications to tenants, SDN controller, network function virtualized
   manager (NFVM), SFC controller and the service function node.  With
   the orchestration, the SDN controller, SFC controller and the NFV
   manager work in coordination to provide the auto-deployed services
   such as VPC, VAS of layer 4 - layer 7 and so on.

   Tenants make the requirement of services in the service applications.
   Service application records tenants' network and service requirements
   and translates them into the SDN controller, SFC controller and the
   NFV managers with the logical network mapping to the physical
   network.  The orchestrator including the virtualized platform is in
   charge of the orchestration and management of NFV infrastructure and
   software resources, and realizing network services.  The SDN
   controller is a logically centralized entity with a general view of
   the network and in charge of SDN data paths, while the SFC controller
   is in central control of the service function chain according to the
   requirements from the service applications.  The NFV manager is
   responsible for NFV lifecycle management such as installation,
   update, query, scaling and termination.  In the bottom, network
   elements are the resource instances which can be a virtual instance
   such as a virtual machine or be embedded in a physical network
   element such as the virtual load balance instances or the physical
   firewall located in the resource pool.



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    --------------------------
    |                        |
    |  Service Application   +---------------------------
    |                        |                          |
    ----+--------------+------                          |
        |              |                                |
        |              |                                |
        |     ---------+-------                         |
        |     |               |                         |
        |     | Orchestrator  +----------------------   |
        |     |               |                     |   |
        |     ----+---------+--                     |   |
        |         |         |                       |   |
        |         |         |                       |   |
     ---+---------+----   --+---------------   -----+---+------
     |                |   |                |   |              |
     | SDN Controller |   | SFC Controller |   |  NFV manager |
     |                |   |                |   |              |
     ---+--------------   ---------+--------   ----------------
        |                          |
   -----+--------------------------+---------------------------
   |                                                          |
   |                    -----   -----   -----    ------       |
   |                    |VSW|   |VSW|   |VSW|    | VR |       |
   |                    -----   -----   -----    ------       |
   |                                                          |
   |         ------   ------   ------   ------  -------       |
   |         | VM |   | VM |   | VLB|   | VFW|  | DPI |       |
   |         ------   ------   ------   ------  -------       |
   |                                                          |
   |   network element                                        |
   ------------------------------------------------------------


            Figure 1: SDN and NFV usecase in cloud datacenters

5.  Resolution test of SDN and NFV in cloud datacenters

   The resolution test is based on the architecture introduced with the
   KVM virtualized platform, and Openstack as the orchestrator.  In the
   resolution test, the whole systems, network architecture, SDN
   controller, and forwarding devices are tested of functions,
   performances and security under normal and stress conditions.








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6.  Problems and aspects to be considered in the trail deployment

   It's found out that some key problems exist when introducing SDN and
   NFV technology into cloud datacenters under the resolution tests and
   the practical trail.  Problems rely on aspects such as virtualized
   platforms, network architectures, interface standardization, and some
   others listed as follows.

   (1)Virtualized platforms

   KVM virtualized platform is adopted in our test.  However, other
   virtualized platforms are not well supported by Openstack.  The main
   reason relies on that Openstack is an open-source cloud operating
   system developing based on KVM platform, which is widely used in
   public cloud datacenters.  Actually in the private cloud datacenters,
   other virtualized platforms such as VMware and XEN are widely
   adopted.  Thus more work needs to be focused on other virtualized
   platforms carrying on SDN technology with platforms of much more open
   interfaces and more interface docking attempts.

   (2) Network architecture

   The network architecture of SDN is clear according to other
   standardization organizations with hierarchical layers of application
   layer, orchestrator, controlling layer and forwarding layer.  When
   adding the virtualized network elements into the SDN architecture,
   problems arise around the network architecture of SDN and NFV co-
   deployed in the cloud datacenters.  How can the orchestration layer,
   SDN controller, SFC controller, NFV manager co-operate in order to
   provide the VPC services and SFC services.  What's the relationship
   and specific role-taking between the service application,
   orchestration layer, SDN controller, SFC controller and NFV manager.
   The specific interfaces between these related parts are obscure as
   well.

   (3) Interface standardization

   Due to the incomplete interface of Openstack, interface
   standardization should be taking into consideration.  Nowadays,
   physical servers are out of the management scope of Openstack.
   Besides, the FW and LB plug-ins are limited into only one vendor.
   Service function chaining interfaces are still under discussion
   without being published.  The specific interfaces between SDN
   controller, SFC controller and NFV manager are obscure as well.
   Above all, the interface standardizations should be kept researching
   on.

   (4) Virtualization high availability



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   As virtual machines and virtualized platforms are brought in,
   reliability can be a problem.  Reliability can be divided into
   several layers: the virtual network elements, Openstack, controller,
   virtual link and so on.  Up to now, Openstack has no ability of high
   availability of its database.  High availability of virtual network
   elements integrated in the SDN architectures are without
   standardization.

   (5) Benchmark standardization

   In the resolution test, it works out that the benchmark
   standardization should be focused on.  In actual test, both
   encapsulation technology of VxLAN and MPLSoGRE exist in the SDN
   overlay resolution with difficult comparison.  Besides, there are two
   realization mechanisms of active and passive trigger mode when SDN
   controller communicates with the forwarding devices.  Thus the
   benchmark of SDN controller performance runs to a problem.

   (6) Practical practice experience

   The technology of NFV and SDN is still in the trial stage which is
   lack of practical practice experience.  According to the scenarios,
   NFV elements can be deployed behind the gateway or in a hang-on mode
   next to the core switch.  Besides, centralized and distributed
   deployments of NAT devices are alternated.  The deployment guidance
   of practical practice is eager.  to be shared.

7.  Conclusion

   SDN and NFV technology has been planned to be co-deployed in the
   cloud datacenters in providing services such as VPC and VAS of
   layer4-layer7.Through the resolution test, we have found out that key
   problems on network architecture, virtualized platform, standard
   interfaces, high availability and practice guidance exist.More tests,
   trails and standardization work need to be conducted in preparing the
   large-scale commercial deployment of SDN and NFV technology in cloud
   datacenters.

8.  Security Considerations

   None.

9.  IANA Considerations

   None.






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10.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 2234, November 1997.

Authors' Addresses

   Rong Gu (editor)
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing  100053
   China

   Email: gurong_cmcc@outlook.com


   Chen Li
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing  100053
   China

   Email: lichenyj@chinamobile.com


   Ruixue Wang
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing  100053
   China


















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