NMRG K. Pentikousis
Internet-Draft EICT
Intended status: Informational M. Sifalakis
Expires: April 30, 2015 University of Basel
October 27, 2014
Autonomic Networking Definitions Revisited
draft-pentikousis-nmrg-andr-01
Abstract
This document revisits the autonomic networking terminology
established in peer-reviewed literature, aiming to contribute to the
ongoing discussion in the IRTF NMRG about how to move forward with
standardizing various autonomic networking aspects.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Operational Considerations and Outlook . . . . . . . . . . . 5
3.1. New Deployment Models . . . . . . . . . . . . . . . . . . 5
3.2. Programmable Network Elements and Functions . . . . . . . 6
3.3. Autonomic Planes . . . . . . . . . . . . . . . . . . . . 6
3.4. DevOps . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Informative References . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The IRTF Network Management Research Group (NMRG) has been working on
a set of definitions for autonomic networking. Defining and agreeing
on autonomic networking terminology is not an easy task as discussed
in [TAN]. In general, autonomic operation is associated with a range
of properties, such as self-configuration, self-healing, self-
optimization, and self-protection [ACDawn]. It is worth pointing out
that although there is some implicit consensus within the autonomic
computing community on the key properties/attributes, in the
autonomic networking community this is not necessarily the case. In
the past, the common ground between different projects and different
contexts of operation was the presence of self-* properties, without
converging to a minimum set or different levels of autonomic behavior
or where this behavior needs to be manifested.
Behringer et al. [I-D.irtf-nmrg-autonomic-network-definitions]
describe a set of design goals and non-goals for autonomic networking
and introduce a model reference architecture in the context of future
IETF standardization [I-D.behringer-autonomic-control-plane].
Prior to this recent effort at the NMRG, autonomic networking has
been the focus of several research projects over the last decade.
For example, Bouabene et al. [ANA] detail an autonomic network
architecture (ANA). Nguengang et al. [UMFSpec] propose a unified
management framework (UMF) which has autonomic properties and
functions at its core. Chaparadza et al. [SelfFI] introduce an
elegant and "standardizable" [sic] generic autonomic networking
architecture (GANA) which they propose to be adopted as a reference
model. GANA was indeed further elaborated under the auspices of ETSI
as a group specification [GANA]. This list of earlier work in only
indicative to the breadth of research in this area over the last
decade. However, standardization remains an open question and
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deployment has been limited to specific mechanisms only
[I-D.irtf-nmrg-an-gap-analysis].
We concur with Behringer et al.
[I-D.irtf-nmrg-autonomic-network-definitions] that for most of the
work in IETF it suffices to define autonomic behaviour at the node
level. However, recent standardization efforts in the IETF, such as,
for example, I2RS [I-D.ietf-i2rs-problem-statement], SFC
[I-D.ietf-sfc-problem-statement], ABNO
[I-D.farrkingel-pce-abno-architecture], SUPA
[I-D.pentikousis-supa-mapping], and LIME to name a few, and new
research groups at the IRTF (SDNRG and proposed NFVRG), indicate that
one may consider that the NMRG should perhaps dig a bit deeper before
finalizing the definitions and goals document. In particular, one
could reconsider the aspects of defining node-level autonomicity
only.
This document revisits the autonomic networking definitions proposed
earlier in the peer-reviewed literature Section 2 ,and relates them
with such recent developments aiming to assist in the definition of
coherent terminology in this emerging area of standardization at the
IETF.
2. Definitions
After some thorough analysis and discussion, Schmid et al. [TAN] put
forward the following definition, which captures in a concrete and
concise manner the essence of autonomicity:
An Autonomic System is a system that operates and serves its
purpose by managing its own self without external intervention
even in case of environmental changes.
Note that the authors explicitly define autonomicity at the system
level, not at the node level. They go on to list the minimum set of
properties that an autonomic system should possess. Namely, an
autonomic system is
o automatic, i.e. it can "self-control its internal functions and
operations"
o adaptive, i.e. it can change its "configuration, state and
functions", and
o aware, i.e. it can "monitor its operational context".
In principle, an autonomic system could wholly replace a non-
autonomic one. In practice, however, real-world deployments will
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include legacy network elements and services as well as new autonomic
ones.
A salient paper in the autonomic networking area is [FOCALE], in
which Strassner et al. lay the foundation for an autonomic network
architecture. We will not delve into the details of FOCALE, but we
do note that the authors define three types of managed components
depending on their autonomic capabilities. In the remainder of this
document we consider that FOCALE "components" equate to network
resources as defined in [I-D.irtf-sdnrg-layer-terminology], i.e. each
network resource is a "physical or virtual component available within
a system", and build on the definitions further.
In this sense, legacy equipment can be seen as autonomically unaware
resources, and can only be managed using traditional mechanisms. In
practice, field equipment could be upgraded to support certain
autonomic features, thus becoming autonomically-aware managed network
resources. This type of network element would typically require a
mediation layer as suggested in [FOCALE] or at the very least certain
system software updates. Finally, a deployment could include fully
autonomically-enabled network resources. FOCALE explicitly aims to
"accommodate legacy components" and foresees the deployment of an
autonomic manager "that orchestrates the behaviour of other autonomic
components in the system."
Figure 1 illustrates a simple sketch of an autonomic networking
control loop, based on Fig. 2 of [FOCALE]. In short, an autonomic
manager gathers data from the managed resource(s), evaluates the
current state, compares it with the desired one, and configures the
managed resource as necessary. As illustrated, this simple system
possess the minimum set of properties introduced above.
+---------------------+
(Maintenance Loop) | Actual vs. desired | Autonomic manager
+-------------->| state evaluation |
| | and decision making |
| +---------o-----------+
v |
+----------------+ | New configuration
| Data gathering | | (Adjustment Loop)
+----------------+ |
^ v
| +------------------+
+----------------o Managed resource |
+------------------+
Figure 1: Simple sketch of an autonomic networking control loop
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Of course, all three types of network resources (autonomically-
unaware, -aware, and -enabled) need to be managed. One viable
approach is proposed by Nguengang et al. [UMFSpec] who describe an
architecture based on the definition of two types of management
systems depending on the capacity of the underlying nodes, namely an
Enhanced Legacy Management System (ELMS) or a Future Management
System (FMS). In this context, it is worth considering the
approaches taken in other disciplines. For example, in aviation,
auto-navigation systems solve this challenge by means of distributed
consensus among an odd-number of controllers/manager that
independently carry out the tasks of data gathering and state
evaluation, and then make an election for each decision. On the
other hand, bio-inspired systems have emergent coordination (of
managers) following principles such as entropy or mass action.
Finally, autonomic properties are highly desirable in the context of
new mobile architectures. For example, Barth and Kuehn [SON4G]
discuss the need for self-* properties in the context of small cell
deployments in 4G/LTE, while Hamalainen et al. [LTESON] and provide
a comprehensive guide and handy references to the efforts in 3GPP
along these lines.
3. Operational Considerations and Outlook
This section briefly describes emerging operational considerations
that in the author's view should be taken into account as we move
forward with autonomic networking standardization in the IETF and
IRTF context.
3.1. New Deployment Models
Strassner et al. [FOCALE] highlight that an important goal of
autonomics is "making the life of the user easier by changing the
focus from a computer-centric to a task-centric model". Deployment
of new network technologies is typically a time-consuming, labour-
intensive and cumbersome task. In the past, we have seen that if the
newly designed infrastructure cannot be managed satisfactorily
adverse results, such as service launch delays, may be inevitable.
As we move forward with new deployment models which are oriented
towards softwarized and cloudified network functions, autonomic
networking principles may prove invaluable.
As per [TAN], autonomic systems are by design programmable, which
bodes well with the emerging deployment models which emphasize
agility and shorter technology introduction cycles. We argue that
autonomic networking definitions, goals and gap analysis within the
context of IETF standardization should take this more into
consideration. Further, recent initiatives such as SUPA
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[I-D.pentikousis-supa-mapping] point towards infrastructures which
are managed through intent (generic policies), for instance, as
opposed to network element specific configuration.
3.2. Programmable Network Elements and Functions
Although the development of models such as FoRCES [RFC5812] coincided
with the core of the above-mentioned autonomic networking research
literature, by and large, the two areas did not cross-pollinate. It
appears that as SDN and NFV principles reach a wider audience of
researchers and practitioners, fully programmable network elements
and functions could be further introduced in autonomic networking
architectures. Indeed, moving towards a "task-centric model" relates
well with other efforts in IETF such as SFC
[I-D.ietf-sfc-problem-statement]
3.3. Autonomic Planes
Recent work at the SDNRG [I-D.irtf-sdnrg-layer-terminology]
highlighted the need for the wider SDN community to think in terms of
control, management, and operational planes comprehensiveness and
complementarity. As we have seen above, earlier work in autonomic
networking has been primarily focusing on management aspects (cf.
[UMFSpec]), while recent work in NMRG is focusing on standardizing an
autonomic networking control plane
[I-D.behringer-autonomic-control-plane].
For an autonomic plane, there is the challenge on "which
functionality to place where". For example, one could consider an
architecture in which all three planes have autonomic features.
Alternatively, one could adopt a knowledge plane approach [KP2003]
establishing a separate, virtual/logical plane. A way forward could
be to consider autonomics in NMRG in the context of programmable
networks and through a more comprehensive manner.
3.4. DevOps
John et al. [NSC] elaborate on the concept of continuous network
service delivery. In this context, the authors argue for the need of
programmable observation points which could be inserted in a dynamic
service chain on demand. They expect that future service provider
DevOps would require new management technologies "based on the
experience from data centers" thus "addressing the challenges of
dynamic service chaining". This bodes well with the model
illustrated in Figure 1 and we could expect more results in this
direction in the future.
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4. Acknowledgements
This document would not have been possible without the stimulating
discussion during the NMRG meeting at IETF 90 in Toronto. Many
thanks to all participants.
5. IANA Considerations
This memo includes no request to IANA.
6. Security Considerations
This document does not propose a new network architecture or protocol
and as such does not have any impact on the security of the Internet.
Autonomic networking introduces a range of opportunities for formal
verification techniques which could increase trustworthiness,
although this is clearly beyond the scope of this first version of
this document. Interested readers should consult [ACSec] for an
early exploration of the issues at hand in the context of autonomic
computing.
7. Informative References
[ACDawn] Ganek, A. G., and T. A. Corbi, "The dawning of the
autonomic computing era", IBM systems Journal, 42(1), 5-18
, 2003.
[ACSec] Chess, D. M., Palmer, C. C., and S. R. White, "Security in
an autonomic computing environment", IBM systems Journal,
42(1), 107-118 , 2003.
[ANA] Bouabene, G., Jelger, C., Tschudin, C., Schmid, S.,
Keller, A., and M. May, "The autonomic network
architecture (ANA)", Journal on Selected Areas in
Communications, 28(1), 4-14 IEEE, 2003.
[FOCALE] Strassner, J., Agoulmine, N., and E. Lehtihet, "FOCALE: A
novel autonomic networking architecture", Proc. Latin
American Autonomic Computing Symposium (LAACS), Campo
Grande, Brazil, July 2006.
[GANA] ETSI GS AFI 002, , "Autonomic network engineering for the
self-managing Future Internet (AFI): GANA Architectural
Reference Model for Autonomic Networking, Cognitive
Networking and Self-Management.", April 2013.
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[I-D.behringer-autonomic-control-plane]
Behringer, M., Bjarnason, S., BL, B., and T. Eckert, "An
Autonomic Control Plane", draft-behringer-autonomic-
control-plane-00 (work in progress), June 2014.
[I-D.farrkingel-pce-abno-architecture]
King, D. and A. Farrel, "A PCE-based Architecture for
Application-based Network Operations", draft-farrkingel-
pce-abno-architecture-13 (work in progress), October 2014.
[I-D.ietf-i2rs-problem-statement]
Atlas, A., Nadeau, T., and D. Ward, "Interface to the
Routing System Problem Statement", draft-ietf-i2rs-
problem-statement-04 (work in progress), June 2014.
[I-D.ietf-sfc-problem-statement]
Quinn, P. and T. Nadeau, "Service Function Chaining
Problem Statement", draft-ietf-sfc-problem-statement-10
(work in progress), August 2014.
[I-D.irtf-nmrg-an-gap-analysis]
Jiang, S., Carpenter, B., and M. Behringer, "Gap Analysis
for Autonomic Networking", draft-irtf-nmrg-an-gap-
analysis-02 (work in progress), October 2014.
[I-D.irtf-nmrg-autonomic-network-definitions]
Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
Networking - Definitions and Design Goals", draft-irtf-
nmrg-autonomic-network-definitions-04 (work in progress),
October 2014.
[I-D.irtf-sdnrg-layer-terminology]
Haleplidis, E., Pentikousis, K., Denazis, S., Salim, J.,
Meyer, D., and O. Koufopavlou, "SDN Layers and
Architecture Terminology", draft-irtf-sdnrg-layer-
terminology-04 (work in progress), October 2014.
[I-D.pentikousis-supa-mapping]
Pentikousis, K., Lin, J., and Y. Zha, "SUPA Configuration
and Policy Mapping", draft-pentikousis-supa-mapping-00
(work in progress), September 2014.
[KP2003] Clark, D. D., Partridge, C. , et al., "A Knowledge Plane
for the Internet", Proc. SIGCOMM, Karlsruhe, Germany ACM,
August 2003.
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[LTESON] Hamalainen, S., Sanneck, H., and C. Sartori, "LTE Self-
Organising Networks (SON): Network Management Automation
for Operational Efficiency", John Wiley & Sons , 2012.
[NSC] John, W., Pentikousis, K., et al., "Research directions in
network service chaining", Proc. SDN for Future Networks
and Services (SDN4FNS), Trento, Italy IEEE, November 2013.
[RFC5812] Halpern, J. and J. Hadi Salim, "Forwarding and Control
Element Separation (ForCES) Forwarding Element Model", RFC
5812, March 2010.
[SON4G] Barth, U., and E. Kuehn, "Self-organization in 4G mobile
networks: Motivation and vision", Proc. 7th International
Symposium on Wireless Communication Systems (ISWCS), York,
UK, pp. 731-735, IEEE, September 2010.
[SelfFI] Chaparadza, R., Papavassiliou, S., et al., "Creating a
viable Evolution Path towards Self-Managing Future
Internet via a Standardizable Reference Model for
Autonomic Network Engineering", Future Internet Assembly
(pp. 136-147) IOS Press, 2009.
[TAN] Schmid, S., Sifalakis, M., and D. Hutchison, "Towards
autonomic networks", Proc. Autonomic Networking, LNCS
4195, pp. 1-11 Springer, 2006.
[UMFSpec] Nguengang, G. (ed.), et al., "UMF Specifications, Release
1", FP7-UNIVERSELF-Deliverable D2.1 , July 2011.
Authors' Addresses
Kostas Pentikousis
EICT GmbH
EUREF-Campus Haus 13
Torgauer Strasse 12-15
10829 Berlin
Germany
Email: k.pentikousis@eict.de
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Manolis Sifalakis
University of Basel
Bernoullistrasse 16
4056 Basel
Switzerland
Email: sifalakis.manos@unibas.ch
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