Internet DRAFT - draft-bormann-core-roadmap
draft-bormann-core-roadmap
CoRE Working Group C. Bormann
Internet-Draft Universitaet Bremen TZI
Intended status: Standards Track October 22, 2013
Expires: April 25, 2014
CoRE Roadmap and Implementation Guide
draft-bormann-core-roadmap-05
Abstract
The CoRE set of protocols, in particular the CoAP protocol, is
defined in draft-ietf-core-coap in conjunction with a number of
specifications that are currently nearing completion. There are also
several dozen more individual Internet-Drafts in various states of
development, with various levels of WG review and interest.
Today, this is simply a bewildering array of documents. Beyond the
main four documents, it is hard to find relevant information and
assess the status of proposals. At the level of Internet-Drafts, the
IETF has only adoption as a WG document to assign status - too crude
an instrument to assess the level of development and standing for
anyone who does not follow the daily proceedings of the WG.
With a more long-term perspective, as additional drafts mature and
existing specifications enter various levels of spec maintenance, the
entirety of these specifications may become harder to understand,
pose specific implementation problems, or be simply inconsistent.
The present guide aims to provide a roadmap to these documents as
well as provide specific advice how to use these specifications in
combination. In certain cases, it may provide clarifications or even
corrections to the specifications referenced.
This guide is intended as a continued work-in-progress, i.e. a long-
lived Internet-Draft, to be updated whenever new information becomes
available and new consensus on how to handle issues is formed.
Similar to the ROHC implementation guide, RFC 4815, it might be
published as an RFC at some future time later in the acceptance curve
of the specifications.
This document does not describe a new protocol or attempt to set a
new standard of any kind - it mostly describes good practice in using
the existing specifications, but it may also document emerging
consensus where a correction needs to be made.
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(TODO: The present version does not completely cover the new
Internet-Drafts submitted concurrently with it; it is to be updated
by the start of IETF88.)
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 25, 2014.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. The Main Four . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. The CoAP protocol . . . . . . . . . . . . . . . . . . . . 4
2.2. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Further reading . . . . . . . . . . . . . . . . . . . . . 6
3. Informational Drafts . . . . . . . . . . . . . . . . . . . . 6
3.1. Implementation . . . . . . . . . . . . . . . . . . . . . 6
3.2. Multicast and Group Communication . . . . . . . . . . . . 7
3.3. Security . . . . . . . . . . . . . . . . . . . . . . . . 8
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3.4. Intermediaries . . . . . . . . . . . . . . . . . . . . . 9
3.5. Congestion Control . . . . . . . . . . . . . . . . . . . 9
4. CoAP over X . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Optional components of CoRE . . . . . . . . . . . . . . . . . 10
5.1. CoAP-misc . . . . . . . . . . . . . . . . . . . . . . . . 10
5.2. Generalizing Media Types . . . . . . . . . . . . . . . . 11
5.3. Patience, Leisure, Pledge, or: Timing extensions . . . . 11
5.4. Extending Observe . . . . . . . . . . . . . . . . . . . . 11
5.5. Service discovery . . . . . . . . . . . . . . . . . . . . 11
5.6. Server discovery, Naming, etc. . . . . . . . . . . . . . 12
5.7. More support for sleepy nodes . . . . . . . . . . . . . . 12
6. Replaced drafts . . . . . . . . . . . . . . . . . . . . . . . 14
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
8. Security Considerations . . . . . . . . . . . . . . . . . . . 15
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . 16
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction
(To be written - for now please see the Abstract.)
1.1. Terminology
This document is a guide. However, it might evolve to make specific
recommendations on how to use standards-track specifications.
Therefore: 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. They indicate requirement levels for compliant CoRE
implementations [RFC2119]. Note that these keywords are not only
used where a correction or clarification is intended; the latter are
explicitly identified as such.
The term "byte" is used in its now customary sense as a synonym for
"octet".
2. The Main Four
The main component of the CoRE architecture is the Constrained
Application Protocol (CoAP). It aims to provide a RESTful transfer
service, not unlike HTTP, but radically simplified for the use on
constrained devices on constrained networks. REST is the
architectural style that informed the design of HTTP [REST]. The
terms "constrained device" and "constrained network" refer to
limited-capability devices such as sensors operating on networks such
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as the IEEE 802.15.4 based 6LoWPAN [RFC4919].
[I-D.ietf-lwig-terminology] provides a more detailed discussion of
what we mean by these terms.
2.1. The CoAP protocol
The CoAP protocol is defined in three specifications:
o [I-D.ietf-core-coap]
o [I-D.ietf-core-block]
o [I-D.ietf-core-observe]
The first specification, [I-D.ietf-core-coap], provides the core
transfer protocol, including the means to provide communication
security using the DTLS protocol [RFC6347] (compare this to the way
[RFC2616] and [RFC2818] define HTTP and HTTPS). The protocol is
structured into a message layer, which provides duplicate detection
and optional message reliability on top of UDP, and a request/
response layer, which provides the usual REST operations GET, PUT,
POST, and DELETE. A highly efficient protocol encoding carries the
4-byte base header, a sequence of _Options_, and the payload (body)
of a message. The main extension points of CoAP are its Options,
similar to the way new header fields are used to extend HTTP.
Since CoAP is a very simple protocol running on top of UDP, it is
limited in its transfer size by the datagram sizes provided by UDP.
As a further constraint, many constrained networks do not provide
good reliability of delivery once their small frame sizes are
exceeded and the adaptation layer is forced to fragment [WEI]. This
may lead to a practical limitation to payload sizes as small as 64
bytes. [I-D.ietf-core-block] extends the base CoAP protocol with
three options that enable _blockwise_ transfer, i.e., splitting up a
larger transfer into a sequence of smaller transactions, as well as
the early determination of the overall size of the resource
representation.
In HTTP, transactions are always client initiated, and it is the
responsibility of the client to perform GET operations again and
again (polling) if it wants to stay up to date about the status of a
resource. This "pull model" becomes expensive in an environment with
limited power, limited network resources, and nodes that sleep most
of the time. Some more or less savory workarounds have been
developed for HTTP [RFC6202], but, as a new protocol, CoAP can do
better. [I-D.ietf-core-observe] extends the base CoAP protocol with
an option that a client can use to indicate its interest in further
updates from a resource. If the server accepts this option, the
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client becomes an _Observer_ of this resource and receives an
asynchronous notification message each time it changes. Each such
notification message is identical in structure to the response to the
initial GET request.
While the "Block" and "Observe" specifications are optional additions
to the CoAP protocol (just as the core specification already defines
14 options most of which will not need to be used in every message),
they together form what is now generally considered to be the CoAP
protocol.
The CoRE Working Group has completed its work on the base CoAP
protocol specification [I-D.ietf-core-coap] and it has been approved
by the IESG for publication as a Standards-Track RFC on 2013-07-15.
The completed document is currently waiting in the RFC editor queue
for two of its normative references in the security area,
[I-D.mcgrew-tls-aes-ccm-ecc] and [I-D.ietf-tls-oob-pubkey], to be
completed and approved.
The other two CoAP specifications are, at the time of this writing,
in the process of being updated based on the comments to the first
Working-Group Last-Call [RFC2418], and in the second Working-Group
Last-Call, respectively; these are prerequisites to submitting them
to the IESG for publication as a Standards-Track RFC.
The specifications, together with link-format (below), have been
widely implemented in highly interoperable implementations: an ETSI
"plugtest" event in March 2012 was attended by 15 organizations with
20 implementations; in over 3000 tests performed only about 6 %
failed; a second plugtest was conducted in November 2012 and led to
some final adjustments of some details in the specifications.
Another plugtest is planned for November 2013 [COAP3].
2.2. Discovery
The fourth specification in the main set now nearing completion does
not extend the CoAP protocol but addresses a different problem.
In the Web, a number of methods for discovery of resources are
common. Initially, Web discovery was just performed by humans based
on an entry resource to a server (e.g., "/index.html"). This
resource then includes links that directly or indirectly allow a
human to reach the other Web resources that make up the Web site.
Web discovery can be performed by machines if standardized interfaces
and resource descriptions are available. Among the component
mechanisms for Web discovery that are standardized in the IETF are
the well-known resource path "/.well-known/..." [RFC5785] and the
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HTTP link header [RFC5988]. Several related techniques are in common
use today.
Clearly, in the machine-to-machine environments that will be typical
of CoAP applications, it is important to enable devices to discover
each other and their resources. Autonomous devices and embedded
systems necessitate uniform, interoperable resource discovery.
A basic component for this is provided by a standardized description
format for the resources a server provides, the _link-format_.
Unless other methods of discovery are available, CoAP servers should
provide such a description via the well-known URI "/.well-known/
core", available for access via a GET request on that URI. (More
advanced resource discovery schemes might make the same description
available by other means, e.g. by posting it to a resource
directory.)
The description format has been adapted from the format used in the
HTTP link header [RFC5988], which is simple and easy to parse. In
contrast to the HTTP specification, link-format is specified as an
Internet media type (what used to be called "MIME type") and intended
to be carried around in the payload [RFC6690].
[RFC6690] was the first RFC of the CoRE working group.
2.3. Further reading
A recent article provides a more detailed overview over the CoRE
documents nearing completion [SB].
While the specification documents themselves have to go into
meticulous details on every aspect of their protocols, they are the
ultimate reference source and are the recommended reading if this
basic overview is not sufficient.
3. Informational Drafts
3.1. Implementation
In the IETF, a separate working group is working on informational
documents concerning guidance in lightweight implementation of
protocols, the LWIG working group. LWIG has several drafts pertinent
here:
[I-D.ietf-lwig-terminology] provides some common terms that are
useful for discussing implementations and specification in the
constrained node network space. Section 2 and 3 of this document are
quite stable at this time; a new section 4 is in preparation that
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will include discussion of power-related terminology.
[I-D.ietf-lwig-cellular] provides a well-founded discussion of
methods for power conservation in CoAP nodes connected via cellular
networks, from which some of the material will be used.
[I-D.ietf-lwig-guidance] was originally intended as the main working
document of the WG. It contains some discussion about CoAP
implementation in its section 3.4.2, including the efficient
representation of managing duplicate detection state.
[I-D.kovatsch-lwig-class1-coap] contains additional considerations
that, over time, might move into [I-D.ietf-lwig-guidance].
[I-D.castellani-lwig-coap-separate-responses] contains some examples
for message exchanges, focusing on elaborating exchanges involving
separate responses. Since IETF86, work is under way to merge the
CoAP-related information from these three drafts into a new document,
[I-D.kovatsch-lwig-coap].
A new working group has been established in the IETF Security Area to
address the use of DTLS In Constrained Environments (DICE); several
drafts are available for discussion at IETF88 in Vancouver. On the
implementation side, two drafts show how to build minimal
implementations of security protocols relevant for CoAP:
[I-D.ietf-lwig-tls-minimal] for TLS, which is relevant for CoAP's use
of DTLS; and [I-D.ietf-lwig-ikev2-minimal] for IKEv2, the protocol
for setting up IPsec security associations. Similarly,
[I-D.hartke-core-codtls] looks specifically into the use of DTLS in
constrained networks. It raises issues that pertain both to the LWIG
and CoRE working groups of the IETF.
Further drafts submitted to LWIG address energy efficient
implementation [I-D.hex-lwig-energy-efficient] and recent
developments in operating systems for constrained devices
[I-D.hahm-lwig-painless-constrained-programming].
After a somewhat slow start, LWIG is now picking up considerable
energy.
3.2. Multicast and Group Communication
As it is based on UDP, CoAP easily supports the use of IP multicast
to confer messages. However, there are difficult issues around
making the desirable multicast applications actually work well.
This led to an additional milestone on the CoRE charter:
Nov 2012: Using CoAP for group communications to IESG as
Informational
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The informational WG draft [I-D.ietf-core-groupcomm] discusses
fundamentals and use cases for group communication with CoAP. This
is now very close to Working Group last call.
[I-D.dijk-core-groupcomm-misc] gives some additional considerations,
listing requirements, providing some taxonomy, proposing deployment
guidelines, and discussing approaches that are not (yet?) in the
focus of the WG. Its section 5 can serve as an overview over the
status of multicast in constrained node/networks.
3.3. Security
Several individual drafts analyze the issues around the security of
constrained devices in constrained networks.
[I-D.garcia-core-security] in particular describes the "Thing
Lifecycle" and discusses resulting architectural considerations.
[I-D.sarikaya-core-secure-bootsolution] documents the approach taken
in the ZigBee IP specification (used in Smart Energy Profile 2.0);
the CoRE WG currently is not working on replicating this
specification as an IETF document.
[I-D.jennings-core-transitive-trust-enrollment] demonstrates a
specific approach to securing the Thing Lifecycle based on defined
roles of security players, including a Manufacturer, an Introducer,
and a Transfer Agent. There is considerable interest in the CoRE
working group to complete one or more specifications in this space.
Further work around Thing Lifecycles was expected to occur in the
SOLACE initiative (Smart Object Lifecycle Architecture for
Constrained Environments), with its early mailing list at
solace@ietf.org -- developed after the model of the COMAN
initiative (Management for Constrained Management Networks and
Devices, coman@ietf.org, [I-D.ersue-constrained-mgmt]).
Besides [I-D.garcia-core-security], recently, more work has been
focused on the Authentication and Authorization aspects of CoRE:
o [I-D.gerdes-core-dcaf-authorize]
o [I-D.greevenbosch-core-authreq]
o [I-D.pporamba-dtls-certkey]
o [I-D.urien-core-racs]
o [I-D.schmitt-two-way-authentication-for-iot]
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o [I-D.seitz-core-sec-usecases]
o [I-D.selander-core-access-control]
o [I-D.zhu-core-groupauth]
3.4. Intermediaries
[I-D.castellani-core-http-mapping] discusses some ideas about what
HTTP/CoAP intermediaries could do beyond the basic mapping defined in
[I-D.ietf-core-coap]; in the IETF86 WG meeting, this document was
agreed as a future working group item (with validation of the
adoption on the mailing list still pending). An earlier version of
this draft was split into the current document describing best
practices for mapping between HTTP and CoAP (beyond what is already
described in [I-D.ietf-core-coap]), and one additional document that
describes usages that serve as additional useful examples for more
advanced forms of mapping, a first draft of the latter is available
in [I-D.castellani-core-advanced-http-mapping].
3.5. Congestion Control
[I-D.ietf-core-coap] only defines a very basic congestion control
scheme that is focused on being safe in a wide variety of
applications. Additional documents will define more advanced
congestion control schemes that can provide more optimized
performance in exchange for more implementation complexity and/or a
narrower field of application.
Several drafts are contributing to this active subject of discussion
in the WG:
| draft-bormann-core-congestion-control | -02 | 2012-08-01 |
| draft-bormann-core-cocoa | -00 | 2012-08-13 |
[I-D.greevenbosch-core-minimum-request-interval] proposes adding an
option that allows a server to indicate its desire for some pacing of
the requests sent to it by one client; enabling a form of server load
control.
4. CoAP over X
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[I-D.becker-core-coap-sms-gprs] shows how to run CoAP over cellular
SMS and in mixed SMS/GPRS environments. This draft optionally makes
use of an SMS-oriented encoding for CoAP that is described in
[I-D.bormann-coap-misc].
[I-D.silverajan-core-coap-alternative-transports] discusses how to
indicate the alternative transport in a URI.
[I-D.li-core-coap-payload-length-option] defines a way to indicate
the length of the payload in case the underlying transport does not
provide a suitable definite length indication.
5. Optional components of CoRE
Additional sub-protocols are being discussed in the IETF that may
become optional protocols in CoREs.
The present document will track these sub-protocols and be amended
once the sub-protocols reach formal status in the IETF.
Since the WG is cautious in adopting additional work while the main
specifications near completion, none of the additional protocols
proposed have become WG documents yet.
5.1. CoAP-misc
One draft is a little different from the other drafts in this
category: [I-D.bormann-coap-misc] is a running document capturing
CoAP extensions that are in various states of being cooked.
Some of these extensions may finally be adopted for the WG documents
and then vanish from CoAP-misc. For other extensions, we may decide
that they are not very good ideas. Instead of deleting them from
CoAP-misc, they are moved to an appendix. This documents the
approach, the best implementation of that approach that was reached,
and the reasons why it was not adopted. This documentation should
spare the WG and its contributors from the continuous reinvention of
bad ideas.
As of the time of writing, the main body of CoAP-misc is almost
empty, as most urgent developments have found their way into the WG
documents, and many other ideas wait in the "nursery" section of the
document.
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5.2. Generalizing Media Types
CoAP defines a registry for combinations of an Internet Media Type
("MIME type") and a Content Encoding (e.g. some form of compression),
enabling its compact encoding of this information in one or two
bytes. Each entry in the registry defines a single, fixed set of
media type parameters (as in ";charset=utf-8"), if any. This does
not work well with media types that rely on more complex combinations
of parameter settings. [I-D.doi-core-parameter-option] proposes to
add an option to carry parameters for media types.
[I-D.fossati-core-multipart-ct] defines a new media type that can
carry multiple embedded representations employing different media
types using a binary type-length-value format.
5.3. Patience, Leisure, Pledge, or: Timing extensions
Several proposals intend to extend the amount of information
available during an exchange about the timing requirements of the
participants.
| draft-li-core-coap-patience-option | -01 | 2012-10-22 |
Another discussion is in Appendix B.4 of [I-D.bormann-coap-misc].
The question of whether some of this functionality should be
introduced into the main WG documents now is currently also the
subject of an active issue tracker ticket [CoRE204].
5.4. Extending Observe
5.5. Service discovery
Basic service discovery is defined in [RFC6690]. A JSON
representation of the same information is defined in
[I-D.ietf-core-links-json]. The intention is to make this
information available in an equivalent format that is more accessible
to classic Web servers, both as a file format (Internet media type)
and as a format that can be used in e.g. a JavaScript API.
[I-D.arkko-core-dev-urn] defines a new Uniform Resource Name (URN)
namespace that can be used to provide hardware device identifiers in
resource descriptions.
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[I-D.ietf-core-interfaces] provides additional semantics that can be
used to make resource descriptions more directly machine-
interpretable. This ties in to a more general discussion about CoRE
profiles that has only just begun.
[I-D.greevenbosch-core-profile-description] ties into this and
defines a basic JSON format for indicating what CoAP Options and what
Content-Formats (still called media-types there) are available for a
resource. At IETF86 there was fairly good consensus in the CoRE WG
that we should be working on something addressing the underlying
problem statement, while there was not yet agreement on the specific
solution.
[I-D.fossati-core-fp-link-format-attribute] defines a link-format
attribute that indicates a certain resource is best reached via a
specific proxy.
5.6. Server discovery, Naming, etc.
On the boundary between service and server discovery, resource
directory servers provide a way to collect resource descriptions from
multiple servers into one accessible location.
[I-D.bormann-core-simple-server-discovery] provided a basic way to
discover such servers in a constrained node/network without
necessarily having to resort to multicast. It has been merged into
[I-D.ietf-core-resource-directory], which defines protocol elements
that can be used for setting up such a resource directory.
An attempt to merge mDNS/DNS-SD-based discovery (colloquially known
as zeroconf or Bonjour), including recent approaches to extend these
for constrained networks, into the picture is documented in
[I-D.vanderstok-core-dna]; at IETF86 the authors showed interest to
continue work on this.
5.7. More support for sleepy nodes
The basic communication model of CoAP was imported from the Web.
This applies well to some communication requirements in constrained
node/networks, but leaves some other requirements open.
The assumption underlying the current set of WG documents is that the
communication layers below the application provide support functions
for sleeping nodes. Adding support at the application layer might be
able to further reduce the power requirements of "sleepy nodes" that
can sleep most of the time.
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[I-D.rahman-core-sleepy-problem-statement] summarizes the overall
problem statement for sleepy nodes without getting into any specific
solution.
A number of drafts aim to extend the CoAP communication model towards
more support for sleepy nodes.
The base CoAP spec [I-D.ietf-core-coap] already provides some
rudimentary support of sleepy nodes by supporting caching in
intermediaries: resources from a sleepy node may be available from a
caching proxy (if previously retrieved) even though the node is
asleep. [I-D.ietf-core-observe] enhances this support by enabling
sleepy nodes to update caching intermediaries on their own schedule.
A number of drafts more extensively extend the concept of an
intermediary by introducing an additional kind of server that is
hosting the resources of the sleepy node:
The approach of [I-D.vial-core-mirror-server] is to store the actual
resource representations in a special type of Resource Directory
called the Mirror Server. Communicating devices can then fetch the
resource from the Mirror Server regardless of the state of the sleepy
server. ([I-D.vial-core-mirror-proxy] simply appears to be a
previous version of this draft.)
Similar to the above, the approach of
[I-D.fossati-core-publish-option] is to temporarily delegate
authority of its resources (when it is sleeping) to a proxy server
that is always on.
Also, the approach of [I-D.giacomin-core-sleepy-option] is to define
a proxy that acts as a store-and-forward agent for a sleepy node.
Other drafts introduce a variety of signaling based approaches to
facilitate communicating with sleepy nodes: The approach of
[I-D.castellani-core-alive] is to define a new CoAP message type
(called "Alive") which the sleepy node multicasts to all interested
devices when it wakes up. The approach of [I-D.rahman-core-sleepy]
is to introduce storing of sleep characteristics in the Resource
Directory. Communicating devices can then query the RD to learn the
sleep status of the sleepy node before attempting communications.
Finally, some drafts build on the concept of the Observe mechanism to
help keep track of the sleepy node information. The approach of
[I-D.fossati-core-monitor-option] is to extend the Observe pattern to
handle the scenario when both server and clients are sleepy nodes.
Note that some of the other drafts (e.g.,
[I-D.vial-core-mirror-server], [I-D.rahman-core-sleepy]) include
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using/extending the Observe mechanism as part of their overall
approach.
Support for sleepy nodes is currently a very active subject of
discussion in the WG; it is clear that there is a high level of
interest in the WG in addressing application-level support for sleepy
nodes in future specifications. See also the discussion of
[I-D.ietf-lwig-cellular] in Section 3.1 above.
6. Replaced drafts
Internet-Drafts often get replaced by merged drafts or get promoted
to WG drafts. As the relationships between drafts are not always
accurately captured by the secretariat tools, this table provides a
mapping from current drafts to any previous drafts they are
replacing:
+------------------------------------+------------------------------+
| current draft | replaced draft |
+------------------------------------+------------------------------+
| [I-D.ietf-core-coap] | draft-shelby-core-coap |
| | |
| [I-D.ietf-core-block] | draft-bormann-core-coap- |
| | block |
| | |
| | draft-li-core-coap-size- |
| | option |
| | |
| [I-D.ietf-core-observe] | draft-hartke-coap-observe |
| | |
| [RFC6690] | draft-shelby-core-link- |
| | format |
| | |
| [I-D.ietf-core-groupcomm] | draft-rahman-core-groupcomm |
| | |
| [I-D.becker-core-coap-sms-gprs] | draft-li-core-coap-over-sms |
| | |
| [I-D.vanderstok-core-dna] | draft-vanderstok-core-bc |
| | |
| [I-D.ietf-core-resource-directory] | draft-bormann-core-simple- |
| | server-discovery |
| | |
| [I-D.greevenbosch-core-minimum- | draft-greevenbosch-core- |
| request-interval] | block-minimum-time |
+------------------------------------+------------------------------+
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Note that draft-scim-core-schema is just named against the naming
conventions and actually unrelated to the CoRE working group.
7. IANA Considerations
This document has no actions for IANA.
8. Security Considerations
(None so far; this section will certainly grow as additional security
considerations beyond those listed in the base specifications become
known.)
9. Acknowledgements
(The concept for this document is borrowed from [RFC4815], which was
invented by Lars-Erik Jonsson. Thanks!)
Akbar Rahman contributed text to this roadmap.
10. References
10.1. Normative References
[I-D.ietf-core-block]
Bormann, C. and Z. Shelby, "Blockwise transfers in CoAP",
draft-ietf-core-block-13 (work in progress), October 2013.
[I-D.ietf-core-coap]
Shelby, Z., Hartke, K., and C. Bormann, "Constrained
Application Protocol (CoAP)", draft-ietf-core-coap-18
(work in progress), June 2013.
[I-D.ietf-core-observe]
Hartke, K., "Observing Resources in CoAP", draft-ietf-
core-observe-11 (work in progress), October 2013.
[I-D.ietf-tls-oob-pubkey]
Wouters, P., Tschofenig, H., Gilmore, J., Weiler, S., and
T. Kivinen, "Using Raw Public Keys in Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", draft-ietf-tls-oob-pubkey-10 (work in progress),
October 2013.
[I-D.mcgrew-tls-aes-ccm-ecc]
McGrew, D., Bailey, D., Campagna, M., and R. Dugal, "AES-
CCM ECC Cipher Suites for TLS", draft-mcgrew-tls-aes-ccm-
ecc-07 (work in progress), August 2013.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785, April
2010.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, January 2012.
[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
Format", RFC 6690, August 2012.
10.2. Informative References
[COAP3] ETSI plugtests, "CoAP 3 & OMA Lightweight M2M", 2013,
<http://www.etsi.org/coap-oma-lightweight-m2m>.
[CoRE204] Bormann, C., "Introduce a minimal version of Pledge", CoRE
ticket #204, 2012,
<http://trac.tools.ietf.org/wg/core/trac/ticket/204>.
[I-D.arkko-core-dev-urn]
Arkko, J., Jennings, C., and Z. Shelby, "Uniform Resource
Names for Device Identifiers", draft-arkko-core-dev-urn-03
(work in progress), July 2012.
[I-D.becker-core-coap-sms-gprs]
Becker, M., Li, K., Poetsch, T., and K. Kuladinithi,
"Transport of CoAP over SMS", draft-becker-core-coap-sms-
gprs-04 (work in progress), August 2013.
[I-D.bormann-coap-misc]
Bormann, C. and K. Hartke, "Miscellaneous additions to
CoAP", draft-bormann-coap-misc-25 (work in progress), May
2013.
[I-D.bormann-core-simple-server-discovery]
Bormann, C., "CoRE Simple Server Discovery", draft-
bormann-core-simple-server-discovery-01 (work in
progress), March 2012.
[I-D.castellani-core-advanced-http-mapping]
Castellani, A., Loreto, S., Rahman, A., Fossati, T., and
E. Dijk, "Best Practices for HTTP-CoAP Mapping
Implementation", draft-castellani-core-advanced-http-
mapping-02 (work in progress), July 2013.
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[I-D.castellani-core-alive]
Castellani, A. and S. Loreto, "CoAP Alive Message", draft-
castellani-core-alive-00 (work in progress), March 2012.
[I-D.castellani-core-http-mapping]
Castellani, A., Loreto, S., Rahman, A., Fossati, T., and
E. Dijk, "Best Practices for HTTP-CoAP Mapping
Implementation", draft-castellani-core-http-mapping-07
(work in progress), February 2013.
[I-D.castellani-lwig-coap-separate-responses]
Castellani, A., "Learning CoAP separate responses by
examples", draft-castellani-lwig-coap-separate-
responses-00 (work in progress), March 2012.
[I-D.dijk-core-groupcomm-misc]
Dijk, E. and A. Rahman, "Miscellaneous CoAP Group
Communication Topics", draft-dijk-core-groupcomm-misc-04
(work in progress), June 2013.
[I-D.doi-core-parameter-option]
Doi, Y. and K. Lynn, "CoAP Content-Type Parameter Option",
draft-doi-core-parameter-option-03 (work in progress),
August 2013.
[I-D.ersue-constrained-mgmt]
Ersue, M., Romascanu, D., and J. Schoenwaelder,
"Management of Networks with Constrained Devices: Problem
Statement, Use Cases and Requirements", draft-ersue-
constrained-mgmt-03 (work in progress), February 2013.
[I-D.fossati-core-fp-link-format-attribute]
Fossati, T. and S. Loreto, "Resource Discovery through
Proxies", draft-fossati-core-fp-link-format-attribute-00
(work in progress), July 2012.
[I-D.fossati-core-monitor-option]
Fossati, T., Giacomin, P., and S. Loreto, "Monitor Option
for CoAP", draft-fossati-core-monitor-option-00 (work in
progress), July 2012.
[I-D.fossati-core-multipart-ct]
Fossati, T., "Multipart Content-Format Encoding for CoAP",
draft-fossati-core-multipart-ct-03 (work in progress),
October 2013.
[I-D.fossati-core-publish-option]
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Fossati, T., Giacomin, P., and S. Loreto, "Publish Option
for CoAP", draft-fossati-core-publish-option-02 (work in
progress), October 2013.
[I-D.garcia-core-security]
Garcia-Morchon, O., Kumar, S., Keoh, S., Hummen, R., and
R. Struik, "Security Considerations in the IP-based
Internet of Things", draft-garcia-core-security-06 (work
in progress), September 2013.
[I-D.gerdes-core-dcaf-authorize]
Gerdes, S., Bergmann, O., and C. Bormann, "Delegated CoAP
Authorization Function (DCAF)", draft-gerdes-core-dcaf-
authorize-00 (work in progress), July 2013.
[I-D.giacomin-core-sleepy-option]
Fossati, T., Giacomin, P., Loreto, S., and M. Rossini,
"Sleepy Option for CoAP", draft-giacomin-core-sleepy-
option-00 (work in progress), February 2012.
[I-D.greevenbosch-core-authreq]
Greevenbosch, B., "Use cases and requirements for
authentication and authorisation in CoAP", draft-
greevenbosch-core-authreq-00 (work in progress), September
2013.
[I-D.greevenbosch-core-minimum-request-interval]
Greevenbosch, B., "CoAP Minimum Request Interval", draft-
greevenbosch-core-minimum-request-interval-01 (work in
progress), April 2013.
[I-D.greevenbosch-core-profile-description]
Greevenbosch, B., Hoebeke, J., Ishaq, I., and F. Abeele,
"CoAP Profile Description Format", draft-greevenbosch-
core-profile-description-02 (work in progress), June 2013.
[I-D.hahm-lwig-painless-constrained-programming]
Hahm, O., Baccelli, E., and K. Schleiser, "Painless Class
1 Devices Programming", draft-hahm-lwig-painless-
constrained-programming-00 (work in progress), March 2013.
[I-D.hartke-core-codtls]
Hartke, K. and O. Bergmann, "Datagram Transport Layer
Security in Constrained Environments", draft-hartke-core-
codtls-02 (work in progress), July 2012.
[I-D.hex-lwig-energy-efficient]
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Cao, Z., He, X., Kovatsch, M., Tian, H., and C. Gomez,
"Energy Efficient Implementation of IETF Constrained
Protocol Suite", draft-hex-lwig-energy-efficient-02 (work
in progress), October 2013.
[I-D.ietf-core-groupcomm]
Rahman, A. and E. Dijk, "Group Communication for CoAP",
draft-ietf-core-groupcomm-16 (work in progress), October
2013.
[I-D.ietf-core-interfaces]
Shelby, Z. and M. Vial, "CoRE Interfaces", draft-ietf-
core-interfaces-00 (work in progress), June 2013.
[I-D.ietf-core-links-json]
Bormann, C., "Representing CoRE Link Collections in JSON",
draft-ietf-core-links-json-00 (work in progress), June
2013.
[I-D.ietf-core-resource-directory]
Shelby, Z., Krco, S., and C. Bormann, "CoRE Resource
Directory", draft-ietf-core-resource-directory-00 (work in
progress), June 2013.
[I-D.ietf-lwig-cellular]
Arkko, J., Eriksson, A., and A. Keranen, "Building Power-
Efficient CoAP Devices for Cellular Networks", draft-ietf-
lwig-cellular-00 (work in progress), August 2013.
[I-D.ietf-lwig-guidance]
Bormann, C., "Guidance for Light-Weight Implementations of
the Internet Protocol Suite", draft-ietf-lwig-guidance-03
(work in progress), February 2013.
[I-D.ietf-lwig-ikev2-minimal]
Kivinen, T., "Minimal IKEv2", draft-ietf-lwig-
ikev2-minimal-01 (work in progress), October 2013.
[I-D.ietf-lwig-terminology]
Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained Node Networks", draft-ietf-lwig-terminology-05
(work in progress), July 2013.
[I-D.ietf-lwig-tls-minimal]
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Kumar, S., Keoh, S., and H. Tschofenig, "A Hitchhiker's
Guide to the (Datagram) Transport Layer Security Protocol
for Smart Objects and Constrained Node Networks", draft-
ietf-lwig-tls-minimal-00 (work in progress), September
2013.
[I-D.jennings-core-transitive-trust-enrollment]
Jennings, C., "Transitive Trust Enrollment for Constrained
Devices", draft-jennings-core-transitive-trust-
enrollment-01 (work in progress), October 2012.
[I-D.kovatsch-lwig-class1-coap]
Kovatsch, M., "Implementing CoAP for Class 1 Devices",
draft-kovatsch-lwig-class1-coap-00 (work in progress),
October 2012.
[I-D.kovatsch-lwig-coap]
Kovatsch, M., Bergmann, O., Dijk, E., He, X., and C.
Bormann, "CoAP Implementation Guidance", draft-kovatsch-
lwig-coap-01 (work in progress), July 2013.
[I-D.li-core-coap-payload-length-option]
Li, K., "CoAP Payload-Length Option Extension", draft-li-
core-coap-payload-length-option-02 (work in progress),
August 2013.
[I-D.pporamba-dtls-certkey]
Porambage, P., Kumar, P., Gurtov, A., Ylianttila, M., and
E. Harjula, "Certificate based keying scheme for DTLS
secured IoT", draft-pporamba-dtls-certkey-00 (work in
progress), June 2013.
[I-D.rahman-core-sleepy-problem-statement]
Rahman, A., Fossati, T., Loreto, S., and M. Vial, "Sleepy
Devices in CoAP - Problem Statement", draft-rahman-core-
sleepy-problem-statement-01 (work in progress), October
2012.
[I-D.rahman-core-sleepy]
Rahman, A., "Enhanced Sleepy Node Support for CoAP",
draft-rahman-core-sleepy-04 (work in progress), October
2013.
[I-D.sarikaya-core-secure-bootsolution]
Sarikaya, B., "Security Bootstrapping Solution for
Resource-Constrained Devices", draft-sarikaya-core-secure-
bootsolution-00 (work in progress), February 2013.
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[I-D.schmitt-two-way-authentication-for-iot]
Schmitt, C., Stiller, B., Kothmayr, T., and W. Hu, "DTLS-
based Security with two-way Authentication for IoT",
draft-schmitt-two-way-authentication-for-iot-01 (work in
progress), October 2013.
[I-D.seitz-core-sec-usecases]
Seitz, L., Gerdes, S., and G. Selander, "Use cases for
CoRE security", draft-seitz-core-sec-usecases-00 (work in
progress), September 2013.
[I-D.selander-core-access-control]
Selander, G., Sethi, M., and L. Seitz, "Access Control
Framework for Constrained Environments", draft-selander-
core-access-control-01 (work in progress), October 2013.
[I-D.silverajan-core-coap-alternative-transports]
Silverajan, B. and T. Savolainen, "CoAP Communication with
Alternative Transports", draft-silverajan-core-coap-
alternative-transports-03 (work in progress), October
2013.
[I-D.urien-core-racs]
Urien, P., "Remote APDU Call Secure (RACS)", draft-urien-
core-racs-00 (work in progress), August 2013.
[I-D.vanderstok-core-dna]
Stok, P., Lynn, K., and A. Brandt, "CoRE Discovery,
Naming, and Addressing", draft-vanderstok-core-dna-02
(work in progress), July 2012.
[I-D.vial-core-mirror-proxy]
Vial, M., "CoRE Mirror Server", draft-vial-core-mirror-
proxy-01 (work in progress), July 2012.
[I-D.vial-core-mirror-server]
Vial, M., "CoRE Mirror Server", draft-vial-core-mirror-
server-01 (work in progress), April 2013.
[I-D.zhu-core-groupauth]
Zhu, J. and M. Qi, "Group Authentication", draft-zhu-core-
groupauth-01 (work in progress), September 2013.
[REST] Fielding, R., "Architectural Styles and the Design of
Network-based Software Architectures", Ph.D. Dissertation,
University of California, Irvine, 2000, <http://
www.ics.uci.edu/~fielding/pubs/dissertation/
fielding_dissertation.pdf>.
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[RFC2418] Bradner, S., "IETF Working Group Guidelines and
Procedures", BCP 25, RFC 2418, September 1998.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC4815] Jonsson, L-E., Sandlund, K., Pelletier, G., and P. Kremer,
"RObust Header Compression (ROHC): Corrections and
Clarifications to RFC 3095", RFC 4815, February 2007.
[RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals", RFC
4919, August 2007.
[RFC5988] Nottingham, M., "Web Linking", RFC 5988, October 2010.
[RFC6202] Loreto, S., Saint-Andre, P., Salsano, S., and G. Wilkins,
"Known Issues and Best Practices for the Use of Long
Polling and Streaming in Bidirectional HTTP", RFC 6202,
April 2011.
[SB] Bormann, C., Castellani, A., and Z. Shelby, "CoAP: An
Application Protocol for Billions of Tiny Internet Nodes",
DOI 10.1109/MIC.2012.29, 2012.
[WEI] Shelby, Z. and C. Bormann, "6LoWPAN: the Wireless Embedded
Internet", ISBN 9780470747995, 2009.
Author's Address
Carsten Bormann
Universitaet Bremen TZI
Postfach 330440
Bremen D-28359
Germany
Phone: +49-421-218-63921
Email: cabo@tzi.org
Bormann Expires April 25, 2014 [Page 22]
