ETSI GS NFV-REL 001 V1.1.1 (2015-01)

Network Functions Virtualisation (NFV); Resiliency Requirements

DGS/NFV-REL001

General Information

• Status: Published
• Publication Date: 06-Jan-2015
• Technical Committee: NFV REL - Reliability & Availability
• Current Stage: 12 - Completion
• Due Date: 02-Feb-2015
• Completion Date: 07-Jan-2015

Standards Content (Sample)

ETSI GS NFV-REL 001 V1.1.1 (2015-01)






GROUP SPECIFICATION
Network Functions Virtualisation (NFV);
Resiliency Requirements
Disclaimer
This document has been produced and approved by the Network Functions Virtualisation (NFV) ETSI Industry Specification
Group (ISG) and represents the views of those members who participated in this ISG.
It does not necessarily represent the views of the entire ETSI membership.

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2 ETSI GS NFV-REL 001 V1.1.1 (2015-01)



Reference
DGS/NFV-REL001
Keywords
availability, network, network monitoring,
reliability, resilience
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3 ETSI GS NFV-REL 001 V1.1.1 (2015-01)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definitions abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Resiliency Problem Description & Objectives . 11
4.1 Problem Description . 11
4.2 Network Function Virtualisation Resiliency Objectives . 12
4.2.1 Service Continuity . 12
4.2.2 Automated recovery from failures . 13
4.2.3 No single point of failure . 13
4.2.4 Multi-vendor environment . 14
4.2.5 Hybrid Infrastructure . 14
5 Use Case Analysis and Service Requirements . 14
5.1 Resiliency Use Cases. 14
5.1.1 Service continuity . 14
5.1.2 Network topology transparency . 15
5.1.3 Regression and pre-emption . 16
5.1.4 Spatial distribution . 16
5.1.5 Service chaining . 17
5.2 Use Case Analysis . 17
5.2.1 Service continuity . 17
5.2.2 Network topology transparency . 18
5.2.3 Regression and pre-emption . 18
5.2.4 Distributed resiliency . 18
5.3 Aspects and levels of resiliency . 18
5.4 Service Requirements . 19
6 Resiliency Principles in NFV Environments . 19
6.1 Prerequisites . 19
6.2 Trade-offs . 21
6.3 Resiliency Enablers . 21
6.4 Resilient System Behaviour . 22
7 Service Availability . 23
7.1 Introduction . 23
7.2 Service Availability in NFV . 23
7.3 Service Availability Classification Levels . 24
7.3.1 General description . 24
7.3.2 Service Availability Level . 26
7.3.3 Example Configuration of Service Ava ilability . 27
7.3.4 Requirements . 28
7.4 Metrics for Service Availability . 29
7.4.1 Metrics of Service Accessibility . 30
7.4.2 Service Continuity Metrics . 30
7.4.3 Requirements . 31
8 Fault Management in NFV . 31
8.1 Categories of fault and challenge domains . 35
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8.1.1 VNF Failure Modes . 36
8.1.2 Faults and challenges of virtualisation . 36
9 Failure Prevention . 38
9.1 Concepts . 38
9.2 Failure Containment . 39
9.3 Failure Prediction . 40
9.4 Overload prevention . 41
9.5 Prevention of Single Point of Failure . 42
10 Failure Detection and Remediation . 42
10.1 Architecture Models . 42
10.2 Failure types . 42
10.2.1 Software failures . 42
10.2.2 Hardware Failure Detection . 43
10.3 Cross-Layer Monitoring . 44
10.4 Fault Correlation . 45
10.5 Assess existing "liveness" Checking Mechanisms for Virtual Environments . 46
10.5.1 Heartbeat . 46
10.5.2 Watchdog . 47
10.6 VNF Failure Detection and Remediation . 48
10.7 NFV-MANO Failure Detection and Remediation . 48
10.8 Requirements . 48
10.8.1 Hardware failure detection . 48
10.8.2 Fault Correlation Requirements . 49
10.8.3 Health Checking . 49
10.8.4 VNF Failure Detection and Remediation . 49
10.8.5 NFV-MANO Failure Detection and Remediation . 50
11 Resiliency Flows . 50
11.1 Failure on the NFVI level . 50
11.1.1 Physical NIC bonding . 51
11.1.2 NIC bonding of virtual NICs . 52
11.1.3 VNF internal failover mechanism . 53
11.1.4 VNF agnostic failover mechanism . 54
11.1.5 System recovery . 55
11.2 Failure at the VNF/VNFC level . 55
11.2.1 Stateful VNF protection with external state . 55
11.2.2 Stateless VNF fail-over and restoration . 58
12 Deployment and Engineering Guidelines . 59
12.1 Introduction . 59
12.2 Deployment guidelines in NFV . 59
12.2.1 Network Function Virtualisation Management and Orchestration . 60
12.3 Virtualised Network Function (VNF). 63
12.4 Network Function Virtualisation Infrastructure (NFVI) . 64
12.4.1 Hardware resources (Compute, Storage, Network) . 64
12.4.2 Virtualisation Layer . 65
12.5 High Availability of Management and Orchestration. 66
12.6 End-to-end Service Availability . 66
Annex A (informative): Fault and Challenge Catalogue . 69
A.1 On-demand self-service . 69
A.2 Broad network access . 70
A.3 Virtualisation . 72
A.4 Rapid elasticity . 74
A.5 Resource pooling . 75
A.6 Measured Service . 76
A.7 Organizational issues . 78
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A.8 Physical cloud infrastructure . 79
Annex B (informative): Authors & contributors . 81
History . 82

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Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Group Specification (GS) has been produced by ETSI Industry Specification Group (ISG) Network Functions
Virtualisation (NFV).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "may not", "need", "need not", "will",
"will not", "can" and "cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms
for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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1 Scope
The present document focuses on unique aspects related to network and service resiliency in a virtualised network
environment. The challenges result from failures of virtualised network functions, failures of the underlying hardware
and software infrastructure arising from conditions such as design faults, intrinsic wear out, operational mistakes, or
other adverse conditions, e.g. natural disasters, excessive traffic demand, etc.
The scope of the present document includes:
• Usecase analysis for reliability and availability in a virtualised network environment.
• Analysis of service availability levels.
• Identification of requirements for maintaining network resiliency and service availability, the focus being
additional requirements introduced by virtualisation. The mechanisms to be considered include the following:
- Network function migration within and across system boundaries.
- Failure detection and reporting at the various layers.
- Failure prediction, prevention, and remediation.
- State management.
- Solving network availability issues caused by overload/call blocking conditions.
• Engineering and deployment guidelines for maintaining network resiliency and ensuring service availability.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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8 ETSI GS NFV-REL 001 V1.1.1 (2015-01)
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI ETSI GS NFV 002 (V1.1.1): "Network Functions Virtualisation (NFV); Architectural
Framework".
[i.2] ETSI ETSI GS NFV 003 (V1.1.1): "Network Functions Virtualisation (NFV); Terminology for
Main Concepts in NFV".
[i.3] ETSI GS NFV-SWA 001: "Network Functions Virtualisation (NFV); Virtual Network Function
Architecture".
[i.4] ETSI GS NFV-MAN 001: "Network Functions Virtualisation (NFV); Management and
Orchestration".
[i.5] James P.G. Sterbenz, David Hutchison, Egemen K. Çetinkaya, Abdul Jabbar, Justin P. Rohrer,
Marcus Schöller, Paul Smith: "Resilience and Survivability in Communication Networks:
Strategies, Principles, and Survey of Disciplines", Computer Networks: Special Issue on Resilient
and Survivable Networks (COMNET), vol.54 iss.8, June 2010, pp.1245-1265.
[i.6] Jean-Claude Laprie (ed.): "Dependability: Basic Concepts and Terminology", IFIP WG 10.4 -
Dependable Computing and Fault Tolerance (draft), Aug. 1994.
[i.7] Malgorzata Steinder and Adarshpal S. Sethi: "A survey of fault localization techniques in
computer networks", Science of Computer Programming, vol. 53, #2, November 2004, pp.
165-194.
[i.8] Recommendation ITU-T Y.2171 (2006): "Admission control priority levels in Next Generation
Networks".
[i.9] Recommendation ITU-T Y.2172 (2007): "Service restoration priority levels in Next Generation
Networks".
[i.10] Recommendation ITU-T E.800 (2008): "Terms and definitions related to quality of service and
network performance including dependability".
[i.11] Recommendation ITU-T E.412 (2003): "Network management controls".
[i.12] 3GPP TR 32.814: "Telecommunication management; UTRAN and GERAN Key Performance
Indicators (KPI)".
[i.13] ETSI TS 123 060: "General Packet Radio Service (GPRS); Service description; Stage 2".
[i.14] Recommendation ITU-T Y.2801 (2006): "Mobility management requirements for NGN".
[i.15] ETSI TS 123 207: "End-to-end Quality of Service (QoS) concept and architecture".
[i.16] ETSI TS 102 250-2 (V2.2.1): "Speech and multimedia Transmission Quality (STQ); QoS aspects
for popular services in mobile networks; Part 2: Definition of Quality of Service parameters and
their computation".
[i.17] ETSI TS 102 250-5 (V2.2.1): "Speech and multimedia Transmission Quality Aspects (STQ); QoS
aspects for popular services in mobile networks; Part 5: Definition of typical measurement
profiles".
[i.18] ETSI TS 123 380: "IMS Restoration Procedures".
[i.19] T1A1.2 Working Group: "Network survivability performance." Technical Report T1A1.2/93-
001R3, Alliance for Telecommunications Industry Solutions (ATIS), (1993).
[i.20] IETF RFC 5424 (2009): "The Syslog Protocol".
[i.21] IETF RFC 4412 (2006): "Communications Resource Priority for the Session Initiation Protocol
(SIP)".
[i.22] IETF RFC 4594 (2006): "Configuration Guidelines for DiffServ Service Classes".
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9 ETSI GS NFV-REL 001 V1.1.1 (2015-01)
[i.23] IETF RFC 5865 (2010): "A Differentiated Services Code Point (DSCP) for Capacity-Admitted
Traffic".
[i.24] IETF RFC 4090 (2005): "Fast Reroute Extensions to RSVP-TE for LSP Tunnels".
[i.25] QuEST Forum (2006): "TL 9000 (Telecom Leadership 9000)".
[i.26] ETSI NFV-INF 003: "Network Functions Virtualisation (NFV); Infrastructure; Compute Domain".
3 Definitions abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in ETSI GS NFV 003 [i.2] and the following
apply:
availability: availability of an item to be in a state to perform a required function at a given instant of time or at any
instant of time within a given time interval, assuming that the external resources, if required, are provided
NOTE: See [i.10].
challenge: characteristic or condition that may be manifest as an adverse event or condition that impacts the normal
operation
NOTE: See [i.5].
error: discrepancy between a computed, observed, or measured value or condition and a true, specified, or theoretically
correct value or condition
NOTE 1: Error is a consequence of a fault.
NOTE 2: See [i.7].
failure: deviation of the delivered service from fulfilling the system function
NOTE: See [i.6].
fault: adjudged or hypothesized cause of an error
NOTE: See [i.6].
normal operations: state of the network when there are no adverse conditions present
NOTE 1: This loosely corresponds to the conditions for which the system was designed, when the network is not
under attack, the vast majority of network infrastructure is operational, and connectivity is relatively
strong.
NOTE 2: See [i.5].
reliability: probability that an item can perform a required function under stated conditions for a given time interval
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10 ETSI GS NFV-REL 001 V1.1.1 (2015-01)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AAA Authentication, Authorization, Accountability
API Application Programming Interface
BNA Broad Network Access
BSS Business Support System
CIMS Cloud Infrastructure Management System
COTS Commercial-Off-The-Shelf
CPU Central Processing Unit
CRC Cyclic Redundancy Check
CSCF Call Session Control Function
DAS Direct Attached Storage
DDoS Distributed Denial of Service
DIMM Dual In-line Memory Module
DNS Domain Name System
ECC Error Correcting Code
EMS Element Management System
ETS Emergency Telecommunication Service
GERAN GSM Edge Radio Access Network
GGSN Gateway GPRS Support Node
HA High Availability
IMS IP Multimedia Subsystem
IO Inpu
...