Network Working Group B. Carpenter
Internet-Draft Univ. of Auckland
Intended status: Informational S. Jiang
Expires: December 13, 2018 Huawei Technologies Co., Ltd
June 11, 2018
Limited Domains and Internet Protocols
draft-carpenter-limited-domains-00
Abstract
There is a noticeable trend towards network requirements, behaviours
and semantics that are specific to a limited region of the Internet
and a particular set of requirements. Policies, default parameters,
the options supported, the style of network management and security
requirements may vary. This document reviews examples of such
limited domains and emerging solutions. It shows the needs for a
precise definition of a limited domain boundary and for a
corresponding protocol to allow nodes to discover where such a
boundary exists.
Status of This Memo
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This Internet-Draft will expire on December 13, 2018.
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carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Examples of Limited Domain Requirements . . . . . . . . . . . 3
3. Examples of Limited Domain Solutions . . . . . . . . . . . . 5
4. Common Aspects of Limited Domains . . . . . . . . . . . . . . 7
5. The Need to Define a Limited Domain Boundary . . . . . . . . 8
6. Defining Protocol Scope . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
10. Informative References . . . . . . . . . . . . . . . . . . . 8
Appendix A. Change log [RFC Editor: Please remove] . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
As the Internet continues to grow and diversify, with a realistic
prospect of tens of billions of nodes being connected directly and
indirectly, there is a noticeable trend towards local requirements,
behaviours and semantics. The word "local" should be understood in a
special sense, however. In some cases it may refer to geographical
and physical locality - all the nodes in a single building, on a
single campus, or in a given vehicle. In other cases it may refer to
a defined set of users or nodes distributed over a much wider area,
but drawn together by a single virtual network over the Internet, or
a single physical network running partially in parallel with the
Internet. We expand on these possibilities below. To capture the
topic, this document refers to such networks as "limited domains".
The phrase "Balkanization of the Internet" has often been used to
criticise mechanisms that block the free flow of information across
the network. That is not the topic of this document, which does not
discuss filtering mechanisms and does not apply to protocols that are
designed for use across the whole Internet.
The requirements of limited domains will be different in different
scenarios. Policies, default parameters, and the options supported
may vary. Also, the style of network management may vary, between a
completely unmanaged network, one with fully autonomic management,
one with traditional central management, and mixtures of the above.
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Finally, the requirements and solutions for security and privacy may
vary.
This documents analyses and discusses some of the consequences of
this trend, and how it impacts the idea of universal interoperability
in the Internet. In particular, we challenge the notion that all
Internet standards must be universal in scope and applicability. To
the contrary, we assert that some standards need to be specifically
limited in their applicability. This requires that the concepts of a
limited domain, and of its boundary, need to be formalised.
NOTE: This document is incomplete. Comments on the following two
sections are invited before we complete the later sections.
2. Examples of Limited Domain Requirements
This section describes various examples where limited domain
requirements can be identified. It is of course not a complete list.
NOTE: The authors welcome more suggestions and references for this
list.
1. A home network. It will be unmanaged, constructed by a non-
specialist, and will possibly include wiring errors such as
physical loops. It must work with devices "out of the box" as
shipped by their manufacturers and must create adequate security
by default. Remote access may be required. The requirements
and applicable principles are summarised in [RFC7368].
2. A small office network. This is very similar to a home network,
since whoever is in charge will probably have little or no
specialist knowledge, but may have differing security and
privacy requirements. Remote access may be required.
3. A vehicle network. This will be designed by the vehicle
manufacturer but may include devices added by the vehicle's
owner or operator. Parts of the network will have demanding
performance and reliability requirements with implications for
human safety. Remote access may be required to certain
functions, but absolutely forbidden for others. Communication
with other vehicles, roadside infrastructure, and external data
sources will be required. See
[I-D.ietf-ipwave-vehicular-networking] for a survey of use
cases.
4. A building services network. This will be designed specifically
for a particular building, but using standard components.
Additional devices may need to be added at any time. Parts of
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the network may have demanding reliability requirements with
implications for human safety. Remote access may be required to
certain functions, but absolutely forbidden for others.
[I-D.martocci-6lowapp-building-applications] (need current
reference!)
5. Supervisory Control And Data Acquisition (SCADA) networks in
general, which will exhibit widely differing requirements,
including tough real-time performance targets, of which building
networks are a simple example. See for example
[I-D.ietf-detnet-use-cases]
6. The three preceding cases will all include sensors, but some
networks may be specifically limited to sensors and the
collection and processing of sensor data. They may be in remote
or technically challenging locations and installed by non-
specialists.
7. "Traditional" enterprise and campus networks, which may be
spread over many kilometres and over multiple separate sites.
8. Data centres and hosting centres, or distributed services acting
as such centres. These will have high performance, security and
privacy requirements and will typically include large numbers of
independent "tenant" networks overlaid on shared infrastructure.
9. Content Delivery Networks, comprising distributed data centres
and the paths between them, spanning thousands of kilometres.
10. Internet of Things (IoT) networks. While this term is very
flexible and covers many innovative types of network, it seems
reasonable to assert that many IoT edge networks will in fact
have special requirements and protocols that are useful only
within a specific domain, and that these protocols cannot, and
for security reasons should not, run over the Internet as a
whole.
Two other concepts, while not tied to specific network types, also
strongly depend on the concept of limited domains:
1. Intent Based Networking. In this concept, a network domain is
configured and managed in accordance with an abstract policy
known as "Intent", to ensure that the network performs as
required [I-D.moulchan-nmrg-network-intent-concepts]. Whatever
technologies are used to support this, they will be applied
within the domain boundary.
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2. Network Slicing. A network slice is a virtual network that
consists of a managed set of resources carved off from a larger
network [I-D.geng-netslices-architecture]. Whatever technologies
are used to support slicing, they will require a clear definition
of the boundary of a given slice.
While it is clearly desirable to use common solutions, and therefore
common standards, wherever possible, it is increasingly difficult to
do so while satisfying the widely varying requirements outlined
above. However, there is a tendency when new protocols and protocol
extensions are proposed to always ask the question "How will this
work across the open Internet?" This document suggests that this is
not always the right question. There are protocols and extensions
that are not intended to work across the open Internet. On the
contrary, their requirements and semantics are specifically limited
(in the sense defined above).
A common argument is that if a protocol is intended for limited use,
the chances are very high that it will in fact be used (or misused)
in other scenarios including the so-called open Internet. This is
undoubtedly true and means that limited use is not an excuse for bad
design or poor security. In fact, a limited use requirement
potentially adds complexity to both the protocol and its security
design, as discussed later.
Nevertheless, because of the diversity of limited environments with
specific requirements that is now emerging, specific standards will
necessarily emerge. There will be attempts to capture each market
sector, but the market will demand standardised limited solutions.
However, the "open Internet" must remain as the universal method of
interconnection. Reconciling these two aspects is a major challenge.
3. Examples of Limited Domain Solutions
This section lists various examples of specific limited domain
solutions that have been proposed or defined. It intentionally does
not include Layer 2 technology solutions, which are by definition
defined for limited domains.
NOTE: Please suggest additional items for this list.
1. Differentiated Services. This mechanism [RFC2474] allows a
network to assign locally significant values to the 6-bit
Differentiated Services Code Point field in any IP packet.
Although there are some recommended codepoint values for specific
per-hop queue management behaviours, these are specifically
intended to be domain-specific codepoints with traffic being
classified, conditioned and re-marked at domain boundaries
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(unless there is an inter-domain agreement that makes re-marking
unnecessary).
2. Network function virtualisation. As described in
[I-D.irtf-nfvrg-gaps-network-virtualization], this general
concept is an open research topic, in which virtual network
functions are orchestrated as part of a distributed system.
Inevitably such orchestration applies to an administrative domain
of some kind, even though cross-domain orchestration is also a
research area.
3. Service Function Chaining (SFC). This technique [RFC7665]
assumes that services within a network are constructed as
sequences of individual functions within a specific SFC-enabled
domain. As that RFC states: "Specific features may need to be
enforced at the boundaries of an SFC-enabled domain, for example
to avoid leaking SFC information". A Network Service Header
(NSH) [RFC8300] is used to encapsulate packets flowing through
the service function chain: "The intended scope of the NSH is for
use within a single provider's operational domain."
4. Data Centre Network Virtualization Overlays. A common
requirement in data centres that host many tenants (clients) is
to provide each one with a secure private network, all running
over the same physical infrastructure. [RFC8151] describes
various use cases for this, and specifications are under
development. These include use cases in which the tenant network
is physically split over several data centres, but which must
appear to the user as a single secure domain.
5. Segment Routing. This is a technique which "steers a packet
through an ordered list of instructions, called segments"
[I-D.ietf-spring-segment-routing]. The semantics of these
instructions are explicitly local to a segment routing domain or
even to a single node. Technically, these segments or
instructions are represented as an MPLS label or an IPv6 address,
which clearly adds a semantic interpretation to them within the
domain.
6. Autonomic Networking. As explained in
[I-D.ietf-anima-reference-model], an autonomic network is also a
security domain within which an autonomic control plane
[I-D.ietf-anima-autonomic-control-plane] is used by service
agents. These service agents manage technical objectives, which
may be locally defined, subject to domain-wide policy. Thus the
domain boundary is important for both security and protocol
purposes.
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7. Homenet. As shown in [RFC7368], a home networking domain has
specific protocol needs that differ from those in an enterprise
network or the Internet as a whole. These include the Home
Network Control Protocol (HNCP) [RFC7788] and a naming and
discovery solution [I-D.ietf-homenet-simple-naming].
8. Creative uses of IPv6 features. As IPv6 enters more general use,
engineers notice that it has much more flexibility than IPv4.
Innovative suggestions have been made for:
* The flow label, e.g. [RFC6294],
[I-D.fioccola-v6ops-ipv6-alt-mark].
* Extension headers, e.g. for segment routing
[I-D.ietf-6man-segment-routing-header].
* Meaningful address bits, e.g. [I-D.jiang-semantic-prefix].
Also, segment routing uses IPv6 addresses as segment
identifiers with specific local meanings
[I-D.ietf-spring-segment-routing].
All of these suggestions are only viable within a specified
domain. The case of the extension header is particularly
interesting, since its existence has been a major "selling point"
for IPv6, but it is notorious that new extension headers are
virtually impossible to deploy across the whole Internet
[RFC7045], [RFC7872]. It is worth noting that extension header
filtering is considered as an important security issue
[I-D.ietf-opsec-ipv6-eh-filtering]. There is considerable
appetite among vendors or operators to have flexibility in
defining extension headers for use in limited or specialised
domains, e.g. [I-D.voyer-6man-extension-header-insertion] and
[BIGIP].
9. Deterministic Networking (DetNet). The Deterministic Networking
Architecture [I-D.ietf-detnet-architecture] and encapsulation
[I-D.ietf-detnet-dp-sol] aim to support flows with extremely low
data loss rates and bounded latency, but only within a part of
the network that is "DetNet aware". Thus, as for differentiated
services above, the concept of a domain is fundamental.
4. Common Aspects of Limited Domains
This section derives common aspects of limited domains from the
examples above.
TBD
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5. The Need to Define a Limited Domain Boundary
This section justifies the need for a precise definition of a limited
domain boundary and for a corresponding protocol to allow nodes to
discover where such a boundary exists.
TBD
6. Defining Protocol Scope
This section suggests that protocols or protocol extensions should,
when appropriate, be standardised to interoperate only within a
Limited Domain Boundary. Such protocols are not required to operate
across the Internet as a whole.
TBD
7. Security Considerations
Clearly, the boundary of a limited domain will almost always also act
as a security boundary. In particular, it will serve as a trust
boundary, and as a boundary of authority for defining capabilities.
Within the boundary, limited-domain protocols or protocol features
will be useful, but they will be meaningless if they enter or leave
the domain.
The security model for a limited-scope protocol must allow for the
boundary, and in particular for a trust model that changes at the
boundary. Typically, credentials will need to be signed by a domain-
specific authority.
8. IANA Considerations
This document makes no request of the IANA.
9. Acknowledgements
Useful comments were received from ...
10. Informative References
[BIGIP] Li, R., "HUAWEI - Big IP Initiative.", 2018,
<https://www.iaria.org/announcements/HuaweiBigIP.pdf>.
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[I-D.fioccola-v6ops-ipv6-alt-mark]
Fioccola, G., Velde, G., Cociglio, M., and P. Muley, "IPv6
Performance Measurement with Alternate Marking Method",
draft-fioccola-v6ops-ipv6-alt-mark-01 (work in progress),
June 2018.
[I-D.geng-netslices-architecture]
67, 4., Dong, J., Bryant, S., kiran.makhijani@huawei.com,
k., Galis, A., Foy, X., and S. Kuklinski, "Network Slicing
Architecture", draft-geng-netslices-architecture-02 (work
in progress), July 2017.
[]
Previdi, S., Filsfils, C., Leddy, J., Matsushima, S., and
d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header
(SRH)", draft-ietf-6man-segment-routing-header-13 (work in
progress), May 2018.
[I-D.ietf-anima-autonomic-control-plane]
Eckert, T., Behringer, M., and S. Bjarnason, "An Autonomic
Control Plane (ACP)", draft-ietf-anima-autonomic-control-
plane-16 (work in progress), June 2018.
[I-D.ietf-anima-reference-model]
Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
and J. Nobre, "A Reference Model for Autonomic
Networking", draft-ietf-anima-reference-model-06 (work in
progress), February 2018.
[I-D.ietf-detnet-architecture]
Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", draft-ietf-
detnet-architecture-05 (work in progress), May 2018.
[I-D.ietf-detnet-dp-sol]
Korhonen, J., Andersson, L., Jiang, Y., Finn, N., Varga,
B., Farkas, J., Bernardos, C., Mizrahi, T., and L. Berger,
"DetNet Data Plane Encapsulation", draft-ietf-detnet-dp-
sol-04 (work in progress), March 2018.
[I-D.ietf-detnet-use-cases]
Grossman, E., "Deterministic Networking Use Cases", draft-
ietf-detnet-use-cases-16 (work in progress), May 2018.
[I-D.ietf-homenet-simple-naming]
Lemon, T., Migault, D., and S. Cheshire, "Simple Homenet
Naming and Service Discovery Architecture", draft-ietf-
homenet-simple-naming-01 (work in progress), March 2018.
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[I-D.ietf-ipwave-vehicular-networking]
Jeong, J., "IP-based Vehicular Networking: Use Cases,
Survey and Problem Statement", draft-ietf-ipwave-
vehicular-networking-02 (work in progress), March 2018.
[I-D.ietf-opsec-ipv6-eh-filtering]
Gont, F. and W. LIU, "Recommendations on the Filtering of
IPv6 Packets Containing IPv6 Extension Headers", draft-
ietf-opsec-ipv6-eh-filtering-05 (work in progress), March
2018.
[I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing
Architecture", draft-ietf-spring-segment-routing-15 (work
in progress), January 2018.
[I-D.irtf-nfvrg-gaps-network-virtualization]
Bernardos, C., Rahman, A., Zuniga, J., Contreras, L.,
Aranda, P., and P. Lynch, "Network Virtualization Research
Challenges", draft-irtf-nfvrg-gaps-network-
virtualization-09 (work in progress), February 2018.
[I-D.jiang-semantic-prefix]
Jiang, S., Qiong, Q., Farrer, I., Bo, Y., and T. Yang,
"Analysis of Semantic Embedded IPv6 Address Schemas",
draft-jiang-semantic-prefix-06 (work in progress), July
2013.
[I-D.martocci-6lowapp-building-applications]
Martocci, J., Schoofs, A., and P. Stok, "Commercial
Building Applications Requirements", draft-martocci-
6lowapp-building-applications-01 (work in progress), July
2010.
[I-D.moulchan-nmrg-network-intent-concepts]
Sivakumar, K. and M. Chandramouli, "Concepts of Network
Intent", draft-moulchan-nmrg-network-intent-concepts-00
(work in progress), October 2017.
[]
daniel.voyer@bell.ca, d., Leddy, J., Filsfils, C., Dukes,
D., Previdi, S., and S. Matsushima, "Insertion of IPv6
Segment Routing Headers in a Controlled Domain", draft-
voyer-6man-extension-header-insertion-03 (work in
progress), May 2018.
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[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>.
[RFC6294] Hu, Q. and B. Carpenter, "Survey of Proposed Use Cases for
the IPv6 Flow Label", RFC 6294, DOI 10.17487/RFC6294, June
2011, <https://www.rfc-editor.org/info/rfc6294>.
[RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing
of IPv6 Extension Headers", RFC 7045,
DOI 10.17487/RFC7045, December 2013,
<https://www.rfc-editor.org/info/rfc7045>.
[RFC7368] Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J.
Weil, "IPv6 Home Networking Architecture Principles",
RFC 7368, DOI 10.17487/RFC7368, October 2014,
<https://www.rfc-editor.org/info/rfc7368>.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015,
<https://www.rfc-editor.org/info/rfc7665>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <https://www.rfc-editor.org/info/rfc7788>.
[RFC7872] Gont, F., Linkova, J., Chown, T., and W. Liu,
"Observations on the Dropping of Packets with IPv6
Extension Headers in the Real World", RFC 7872,
DOI 10.17487/RFC7872, June 2016,
<https://www.rfc-editor.org/info/rfc7872>.
[RFC8151] Yong, L., Dunbar, L., Toy, M., Isaac, A., and V. Manral,
"Use Cases for Data Center Network Virtualization Overlay
Networks", RFC 8151, DOI 10.17487/RFC8151, May 2017,
<https://www.rfc-editor.org/info/rfc8151>.
[RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed.,
"Network Service Header (NSH)", RFC 8300,
DOI 10.17487/RFC8300, January 2018,
<https://www.rfc-editor.org/info/rfc8300>.
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Appendix A. Change log [RFC Editor: Please remove]
draft-carpenter-limited-domains, 2018-06-11:
Initial version
Authors' Addresses
Brian Carpenter
Department of Computer Science
University of Auckland
PB 92019
Auckland 1142
New Zealand
Email: brian.e.carpenter@gmail.com
Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: jiangsheng@huawei.com
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