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Versions: 00 01                                                         
Network Working Group                                             T. Kim
Internet-Draft                                                   E. Paik
Intended status: Informational                                        KT
Expires: April 21, 2016                                 October 19, 2015


Considerations for Benchmarking High Availability of NFV Infrastructure
                       draft-kim-bmwg-ha-nfvi-00

Abstract

   This documents lists additional considerations and strategies for
   benchmarking high availability of NFV infrastructure when network
   functions are virtualized and performed in NFV infrastructure.

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].

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-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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 April 21, 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



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   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Considerations for Benchmarking High Availability of NFV
       Infrastructure  . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Definitions for High Availability Benchmarking Test . . .   3
     2.2.  Configuration Parameters for Benchmarking Test  . . . . .   3
   3.  High Availability Benchmarking test strategies  . . . . . . .   4
     3.1.  Single Point of Failure Check . . . . . . . . . . . . . .   4
     3.2.  Failover Time Check . . . . . . . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   As both amount and variety of traffic massively increase, operators
   are adopting SDN and NFV, the new paradigm of networking, in order to
   secure scalability and flexibility.  Service provider and venders are
   developing SDN and NFV solutions and VNF(Virtual Network Function) to
   reduce CAPEX and OPEX, focusing on the increment of the scalability
   and flexibility of the network with programmable networking.

   To replace the legacy network devices with VNFs and to select the
   fittest one from various products of vender, operators want to ensure
   the availability and resiliency of the VNF products and their
   infrastructures.  There also exist fears on the immeasurable
   failures.

   Among VNFs, vEPC is getting many attentions and some
   telecommunications company already deployed vEPC partially.
   Currently in 4G mobile communication, the availability reaches
   99.9999%; downtime being 3 seconds per year.  Therefore, VNFs like
   vEPC (virtual Evolved Packet Core) must guarantee the 6-nines to
   replace hardware dedicated network functions.  From the
   telecommunication company's point of view, the availability is the
   most important feature, and the benchmarking tests for the high
   availability of VNFs and NFV infrastructure are also important.  This
   document investigates considerations for high availability of NFV
   Infrastructure benchmarking test.





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2.  Considerations for Benchmarking High Availability of NFV
    Infrastructure

   This section defines and lists considerations which must be addressed
   to benchmark the high availability of VNFs from the NFV
   infrastructure perspective.

2.1.  Definitions for High Availability Benchmarking Test

   Generally, availability is defined as follows, where MTBF stands for
   Mean Time Between Failure) and MTTR stands for Mean Time To Recovery.

   Availability : MTBF / (MTBF + MTTR)

   A failover procedure is as follows.

   Failure -> Detection -> Isolatation -> Recovery, therefore the time
   to take failover starts from the time when a failure happens.

2.2.  Configuration Parameters for Benchmarking Test

   o  Types of VNFs; depending on the type of VNF, followings are
      different.

      1.  What kind of operations they do

      2.  How many CPUs, MEMs, Storages they need

      3.  What kind of traffic pattern they usually face

   o  The specification of the physical machine which VMs

   o  The mapping ratio of hardware resources to VMs(virtual machine)
      where VNF runs, such as vCPU:pCPU (virtual CPU to physical CPU),
      vMEM:pMEM (virtual memory to physical memory), vNICs as shown
      below.

   o  Types of hypervisor and the different limitations of their roles.

   o  Cloud Design Pattern of NFVI

   o  The composition of network functions in VNFs : for example,
      sometimes in vEPC implementations, PGW(Packet Data Network
      Gateway) and SGW(Serving Gateway) are combined or PGW+SGW+MME.







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 +---------------+                   +---------------+
 | vCPU for VNF1 |                   |               |
 +---------------+                   | vCPU for VNF2 |
 +---------------+                   |               | +---------------+
 | vCPU for VNF2 |                   +---------------+ | vCPU for VNF1 |
 +---------------+                                     +---------------+
 +---------------+ +---------------+ +---------------+ +---------------+
 | vCPU for VNF3 | | vCPU for VNF2 | | vCPU for VNF3 | | vCPU for VNF3 |
 +---------------+ +---------------+ +---------------+ +---------------+
 +---------------+ +---------------+ +---------------+ +---------------+
 |     pCPU 1    | |     pCPU 2    | |    pCPU 3     | |    pCPU 4     |
 +---------------+ +---------------+ +---------------+ +---------------+

3.  High Availability Benchmarking test strategies

   This section discusses benchmarking test strategies for high
   availability of NFV infrastructure.  For the continuity of the
   services, these two must be checked.

3.1.  Single Point of Failure Check

   All devices and software have potential failures, therefore,
   redundancy is mandatory.  First, the redundancy implementation of
   every sing point of NFV infrastructure must be tested as shown below.

   o  Hardware

      *  Power supply

      *  CPU

      *  MEM

      *  Storage

      *  Network :NICs, ports, LAN cable ..

   o  Software

      *  The redundancy of VNFs

      *  The redundancy of VNFs path

      *  The redundancy of OvS

      *  The redundancy of vNICs

      *  The redundancy of VMs



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    +--------------------------------------------------------------+
    | Physical Machine                                             |
    |                                                              |
    |                                                              |
    |  +--------------------------------------------------------+  |
    |  |               Virtual Network Function                 |  |
    |  +--------------------------------------------------------+  |
    |  +--------------------------------------------------------+  |
    |  |                   Virtual Machine                      |  |
    |  +--------------------------------------------------------+  |
    |  +--------------------------------------------------------+  |
    |  |                   Virtual Bridge                       |  |
    |  +--------------------------------------------------------+  |
    |  +--------------------------------------------------------+  |
    |  |                      Hypervisor                        |  |
    |  +--------------------------------------------------------+  |
    |  +--------------------------------------------------------+  |
    |  |                   Operating System                     |  |
    |  +--------------------------------------------------------+  |
    |  +--------------------------------------------------------+  |
    |  |                   Generic Hardware                     |  |
    |  +--------------------------------------------------------+  |
    +--------------------------------------------------------------+

3.2.  Failover Time Check

   Even though the components of NFV infrastructure are redundant,
   failover time can be long.  For example, when a failure happens, the
   VNF with failure stops and should be replaced by backup VNF but the
   time to be shifted to the new VNF can be varied with the VNF;
   stateless or stateful.  Namely, redundancy does not guarantees high
   availability and short failover time is required to reach high
   availability.  This section discusses strategy about measuring
   failover time.

   In order to measure the failover time presicely, the time when
   failure happens must be defined.  Followings are three different
   criteria which is the time when failure happens.

   1.  The time starts when failure actually happens

   2.  The time starts when failure detected by manager or controller

   3.  The time starts when failure event alerts to the operator

   As the actual operations in VNFs and NFV infrastructure start to be
   changed when failure happens, the precise time of the failure
   happened must be the 1.  When measuring the failover time, it starts



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   from the time when the failures happens at a point in NFV
   infrastructure or VNF itself.

4.  Security Considerations

   TBD.

5.  IANA Considerations

   No IANA Action is requested at this time.

6.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

Authors' Addresses

   Taekhee Kim
   KT
   Infra R&D Lab. KT
   17 Woomyeon-dong, Seocho-gu
   Seoul  137-792
   Korea

   Phone: +82-2-526-6688
   Fax:   +82-2-526-5200
   Email: taekhee.kim@kt.com


   EunKyoung Paik
   KT
   Infra R&D Lab. KT
   17 Woomyeon-dong, Seocho-gu
   Seoul  137-792
   Korea

   Phone: +82-2-526-5233
   Fax:   +82-2-526-5200
   Email: eun.paik@kt.com
   URI:   http://mmlab.snu.ac.kr/~eun/








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