-
Notifications
You must be signed in to change notification settings - Fork 4
/
core-charter.txt
40 lines (22 loc) · 9.17 KB
/
core-charter.txt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Charter for Working Group
The CoRE Working Group (WG) provides a framework for resource-oriented applications intended to run on constrained IP networks. A constrained IP network has limited packet sizes, may exhibit a high degree of packet loss, and may have a substantial number of devices that may be powered off at any point in time but periodically "wake up" for brief periods of time. These networks and the nodes within them are characterized by severe limits on throughput, available power, and particularly on the complexity that can be supported with limited code size and limited RAM per node [RFC 7228]. More generally, we speak of constrained node networks whenever at least some of the nodes and networks involved exhibit these characteristics. Low-Power Wireless Personal Area Networks (LoWPANs) are an example of this type of network. Constrained networks can occur as part of home and building automation, energy management, and the Internet of Things.
The CoRE WG will define a framework for a limited class of applications: those that deal with the manipulation of simple resources on constrained networks. This includes applications to monitor simple sensors (e.g., temperature sensors, light sensors, and power meters), to control actuators (e.g., light switches, heating controllers, and door locks), and to manage devices.
The general architecture targeted by the CoRE WG framework consists of nodes on the constrained network, called Devices, that are responsible for one or more Resources that may represent sensors, actuators, combinations of values, and/or other information. Devices send messages to change and query resources on other Devices. A Device can send notifications about changed resource values to Devices that have expressed their interest to receive notification about changes. A Device can also publish or be queried about its resources. Typically, a single physical host on the network would have just one Device but a host might represent multiple logical Devices. The specific terminology to be used here is to be decided by the working group.
As part of the framework for building these applications, the CoRE WG has defined the Constrained Application Protocol (CoAP) for the manipulation of Resources on a Device. CoAP is designed for use between Devices on the same constrained network, between Devices and general nodes on the Internet, and between Devices on different constrained networks both joined by an internet. CoAP is also being used via other mechanisms, such as SMS on mobile communication networks. CoAP targets the type of operating environments defined in the ROLL and 6Lo WGs, which have additional constraints compared to normal IP networks. Nevertheless, the CoAP protocol also operates over traditional IP networks.
There also may be intermediary nodes acting as proxies that possibly also interconnect between other Internet protocols and the Devices using the CoAP protocol. It is worth noting that a proxy does not have to occur at the boundary between the constrained network and the more general network, but can be deployed at various locations in the less-constrained network. The CoRE WG will continue to evolve the support of proxies for CoAP to increase their practical applicability.
CoAP supports various forms of "caching". Beyond the benefits of caching already well known from REST, caching can be used to increase energy savings of low-power nodes by allowing them to be normally-off [RFC 7228]. For example, a temperature sensor might wake up every five minutes and send the current temperature to a proxy that has expressed interest in notifications. When the proxy receives a request over CoAP or HTTP for that temperature resource, it can respond with the last notified value, instead of trying to query the Device which may not be reachable at this time. The CoRE WG will continue to evolve this model to increase its practical applicability.
The CoRE WG will perform maintenance as well as possible updating and complementing on its first four standards-track specifications as required:
- RFC 6690
- RFC 7252
- RFC 7641
- RFC 7959
The CoRE WG will continue to evolve the support for CoAP group communication originally developed in the Experimental RFC 7390. The CoRE WG will not develop a solution for reliable multicast delivery of CoAP messages, which will remain Non-Confirmable when sent over multicast.
RFC 7252 defines a basic HTTP mapping for CoAP, which was further elaborated in RFC 8075. This mapping will be evolved and supported by further documents as required.
CoAP was initially designed to work over UDP and DTLS. Later on, mapping were defined between CoAP and IP-based transports, especially TCP and WebSockets including a secure version over TLS (RFC 8323). The CoRE WG will continue defining transport mappings for alternative transports as required, both IP-based and non IP-based (e.g., SMS and Bluetooth), working with the Security Area on potentially addressing the security gap. This includes defining appropriate URI schemes. Continued compatibility with CoAP over SMS as defined in OMA Lightweight Machine-to-Machine (LwM2M) will be considered. Furthermore, the CoRE WG will work on solutions to facilitate the signaling of transports available to a Device.
The CoRE WG will continue and complete its work on the CoRE Resource Directory (draft-ietf-core-resource-directory), as already partially adopted by OMA LwM2M, and will perform maintenance as well as possible updating, complementing and specification of relevant uses as required. A primary related consideration is the interoperability with DNS-SD and the work of the dnssd WG. The use of CoAP to transport DNS queries and responses will also be investigated. Furthermore, the CoRE WG will also continue and complete its work on enabling broker-based publish-subscribe-style communication over CoAP (draft-ietf-core-coap-pubsub).
The CoRE WG will work on related data formats, such as alternative representations of RFC 6690 link format and RFC 7390 group communication information. Also, the CoRE WG will complete its work on Constrained Resource Identifiers for serializing URI components in CBOR (draft-ietf-core-href). Furthermore, the CoRE WG will develop CoRAL (draft-ietf-core-coral), a constrained RESTful application language suitable also for constrained node networks, which comprises an information model and an interaction model, and is intended for driving automated software agents that navigate a Web application. The CoRE WG will complete the Sensor Measurement Lists (SenML) set of specifications, again with consideration to its adoption in OMA LwM2M.
Besides continuing to examine operational and manageability aspects of the CoAP protocol itself, the CoRE WG will also complete the work on RESTCONF-style management functions available via CoAP that are appropriate for constrained node networks (draft-ietf-core-yang-cbor, draft-ietf-core-sid, draft-ietf-core-comi, draft-ietf-core-yang-library). This requires very close coordination with NETCONF and other operations and management WGs. YANG data models are used for manageability. Note that the YANG modeling language is not a target for change in this process, although additional mechanisms that support YANG modules may be employed in specific cases where significant performance gains are both attainable and required. The CoRE WG will continue to consider the OMA LwM2M management functions as a well-accepted alternative form of management and provide support at the CoAP protocol level where required.
The CoRE WG originally selected DTLS as the basis for the communication security in CoAP. The CoRE WG will work with the TLS WG on the efficiency of this solution. The preferred cipher suites will evolve in cooperation with the TLS WG and CFRG.
The CoRE WG considered object security as originally defined in JOSE and later adapted to the constrained node network requirements in COSE. Building on that, the CoRE WG has defined the Object Security for Constrained RESTful Environments (OSCORE) protocol (RFC 8613) for protecting CoAP messages at the application layer using COSE. The CoRE WG will complete the work on the Group OSCORE protocol (draft-ietf-core-oscore-groupcomm) that enables OSCORE-protection of CoAP messages in group communication environments. Also, the CoRE WG will complete an optimization-oriented profiling of the EDHOC protocol developed in the LAKE WG, when this is used to establish security material for OSCORE (draft-ietf-core-oscore-edhoc). Furthermore, the CoRE WG will perform maintenance as well as possible updating and complementing of the (Group) OSCORE documents above as required.
The ACE WG is expected to provide solutions on authentication and authorization that may need complementary elements on the CoRE side.
The CoRE WG will coordinate on requirements from many organizations and SDOs. The CoRE WG will closely coordinate with other IETF WGs, particularly of the constrained node networks cluster (6Lo, 6TiSCH, LWIG, ROLL, ACE, CBOR, COSE, IOTOPS, LAKE, SUIT), and with further appropriate groups in the IETF OPS and Security Areas. Work on these subjects, as well as on data/interaction models and design patterns (including follow-up work around the CoRE Interfaces draft) will additionally benefit from close cooperation with the Thing-to-Thing Research Group.