Internet DRAFT - draft-kim-bmwg-ha-nfvi

draft-kim-bmwg-ha-nfvi







Network Working Group                                             T. Kim
Internet-Draft                                                   E. Paik
Intended status: Informational                                        KT
Expires: September 22, 2016                               March 21, 2016


Considerations for Benchmarking High Availability of NFV Infrastructure
                       draft-kim-bmwg-ha-nfvi-01

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
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   This Internet-Draft will expire on September 22, 2016.

Copyright Notice

   Copyright (c) 2016 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 . . . . . . . . . . . . . . . . . . .   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   As both the 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 providers
   and venders are developing SDN and NFV solutions to reduce CAPEX and
   OPEX, focusing on the increment of the scalability and flexibility of
   the network with programmable networking.

   While VNF and NFVI replacing the legacy network devices and operators
   selecting the fittest one from various products, operators have
   several issues such as availability, resiliency and immeasurable
   failures.  Above all, they want to ensure the availability of the VNF
   products and their infrastructures.

   Customer expectations on the availability of service are as high as
   five 9s on any infrastructure operators offer because the standard
   availability of 4G mobile communication on the legacy physical
   network among operators has been already five 9s; downtime being 5.26
   minutes per year.  Therefore, to meet the customer expectations,
   services on the NFV infrastructure also need to meet the availability
   to that level, five 9s.  Furthermore, the availability of NFV
   infrastructure needs to be almost six 9s with the consideration of
   the impact of virtualization and interoperability among different
   vendor solutions and layers.  From the operator point of view, the
   availability is the most important feature and the benchmarking tests
   for the high availability of NFV infrastructure are also important.




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   This document investigates considerations for high availability of
   NFV Infrastructure benchmarking test.

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 the NFV infrastructure.

2.1.  Definitions for High Availability Benchmarking Test

   Metrics for high availability Benchmarking of NFV infrastructure are
   as follows.

   o  Failure Detection Time : the time takes to detect a failure

   o  Failure Recovery Time : the time takes to recover the failure

   o  Failure Rates : the frequency of failures

   o  Success Rates of Detection Time : the percentage of success among
      a number of attempts to detect failures

   o  Success Rates of Recovery : the percentage of success among a
      number of attempts to recover the failures

   o  Failure Impact Fraction : the fraction of the infrastructure when
      a failure happens

   Generally, availability and failure rates are defined as follows,
   where MTBF stands for Mean Time Between Failure and MTTR stands for
   Mean Time To Recovery.

   Availability : MTBF / (MTBF + MTTR)

   Failure Rates : 1 - Availability

   A failover procedure in an infrastructure is as follows.

   Failure -> Failure Detection -> Isolation -> Recovery, therefore
   failover time 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



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      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.

 +---------------+                   +---------------+
 | 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, followings needs to be considered.

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




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      *  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

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








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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
   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

   [NFV.REL001]
              "Network Function Virtualization: Resiliency
              Requirements", Group Specification ETSI GS NFV-REL 001
              V1.1.1 (2015-01), January 2015.

   [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>.





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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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