--- 1/draft-ietf-core-resource-directory-00.txt 2013-12-11 19:15:18.114622844 -0800 +++ 2/draft-ietf-core-resource-directory-01.txt 2013-12-11 19:15:18.170624247 -0800 @@ -1,97 +1,100 @@ CoRE Z. Shelby -Internet-Draft Sensinode -Intended status: Standards Track S. Krco -Expires: December 05, 2013 Ericsson - C. Bormann - Universitaet Bremen TZI - June 03, 2013 +Internet-Draft ARM +Intended status: Standards Track C. Bormann +Expires: June 14, 2014 Universitaet Bremen TZI + S. Krco + Ericsson + December 11, 2013 CoRE Resource Directory - draft-ietf-core-resource-directory-00 + draft-ietf-core-resource-directory-01 Abstract In many M2M applications, direct discovery of resources is not practical due to sleeping nodes, disperse networks, or networks where multicast traffic is inefficient. These problems can be solved by employing an entity called a Resource Directory (RD), which hosts descriptions of resources held on other servers, allowing lookups to be performed for those resources. This document specifies the web interfaces that a Resource Directory supports in order for web servers to discover the RD and to register, maintain, lookup and remove resources descriptions. Furthermore, new link attributes useful in conjunction with an RD are defined. -Status of This Memo +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 December 05, 2013. + This Internet-Draft will expire on June 14, 2014. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents - 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3. Architecture and Use Cases . . . . . . . . . . . . . . . . . 4 - 3.1. Use Case: Cellular M2M . . . . . . . . . . . . . . . . . 5 - 3.2. Use Case: Home and Building Automation . . . . . . . . . 5 - 4. Simple Directory Discovery . . . . . . . . . . . . . . . . . 6 - 4.1. Finding a Directory Server . . . . . . . . . . . . . . . 7 + 3. Architecture and Use Cases . . . . . . . . . . . . . . . . . . 4 + 3.1. Use Case: Cellular M2M . . . . . . . . . . . . . . . . . . 5 + 3.2. Use Case: Home and Building Automation . . . . . . . . . . 6 + 4. Simple Directory Discovery . . . . . . . . . . . . . . . . . . 6 + 4.1. Finding a Directory Server . . . . . . . . . . . . . . . . 7 5. Resource Directory Function Set . . . . . . . . . . . . . . . 8 5.1. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 8 - 5.2. Registration . . . . . . . . . . . . . . . . . . . . . . 10 - 5.3. Update . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 5.4. Validation . . . . . . . . . . . . . . . . . . . . . . . 13 - 5.5. Removal . . . . . . . . . . . . . . . . . . . . . . . . . 14 - 6. Group Function Set . . . . . . . . . . . . . . . . . . . . . 15 - 6.1. Register a Group . . . . . . . . . . . . . . . . . . . . 15 + 5.2. Registration . . . . . . . . . . . . . . . . . . . . . . . 10 + 5.3. Update . . . . . . . . . . . . . . . . . . . . . . . . . . 12 + 5.4. Removal . . . . . . . . . . . . . . . . . . . . . . . . . 14 + 6. Group Function Set . . . . . . . . . . . . . . . . . . . . . . 15 + 6.1. Register a Group . . . . . . . . . . . . . . . . . . . . . 15 6.2. Group Removal . . . . . . . . . . . . . . . . . . . . . . 17 - 7. RD Lookup Function Set . . . . . . . . . . . . . . . . . . . 18 - 8. New Link-Format Attributes . . . . . . . . . . . . . . . . . 22 - 8.1. Resource Instance 'ins' attribute . . . . . . . . . . . . 23 - 8.2. Export 'exp' attribute . . . . . . . . . . . . . . . . . 23 - 9. Security Considerations . . . . . . . . . . . . . . . . . . . 23 - 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 - 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 - 12. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 24 - 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 25 - 13.1. Normative References . . . . . . . . . . . . . . . . . . 25 - 13.2. Informative References . . . . . . . . . . . . . . . . . 26 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26 + 7. RD Lookup Function Set . . . . . . . . . . . . . . . . . . . . 18 + 8. New Link-Format Attributes . . . . . . . . . . . . . . . . . . 22 + 8.1. Resource Instance 'ins' attribute . . . . . . . . . . . . 22 + 8.2. Export 'exp' attribute . . . . . . . . . . . . . . . . . . 23 + 9. DNS-SD Mapping . . . . . . . . . . . . . . . . . . . . . . . . 23 + 10. Security Considerations . . . . . . . . . . . . . . . . . . . 23 + 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 + 11.1. Resource Types . . . . . . . . . . . . . . . . . . . . . . 23 + 11.2. Link Extension . . . . . . . . . . . . . . . . . . . . . . 24 + 11.3. RD Parameter Registry . . . . . . . . . . . . . . . . . . 24 + 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25 + 13. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 25 + 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26 + 14.1. Normative References . . . . . . . . . . . . . . . . . . . 26 + 14.2. Informative References . . . . . . . . . . . . . . . . . . 27 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 28 1. Introduction The Constrained RESTful Environments (CoRE) work aims at realizing the REST architecture in a suitable form for the most constrained nodes (e.g. 8-bit microcontrollers with limited RAM and ROM) and networks (e.g. 6LoWPAN). CoRE is aimed at machine-to-machine (M2M) applications such as smart energy and building automation. The discovery of resources offered by a constrained server is very @@ -108,21 +111,21 @@ traffic is inefficient. These problems can be solved by employing an entity called a Resource Directory (RD), which hosts descriptions of resources held on other servers, allowing lookups to be performed for those resources. This document specifies the web interfaces that a Resource Directory supports in order for web servers to discover the RD and to register, maintain, lookup and remove resource descriptions. Furthermore, new link attributes useful in conjunction with a Resource Directory are defined. Although the examples in this document show the use of - these interfaces with CoAP [I-D.ietf-core-coap], they may be applied + these interfaces with CoAP [I-D.ietf-core-coap], they can be applied in an equivalent manner to HTTP [RFC2616]. 2. Terminology 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 [RFC2119]. The term "byte" is used in its now customary sense as a synonym for "octet". This specification requires readers to be familiar with all the terms @@ -305,52 +310,47 @@ 4.1. Finding a Directory Server Endpoints that want to contact a directory server can obtain candidate IP addresses for such servers in a number of ways. In a 6LoWPAN, good candidates can be taken from: o specific static configuration (e.g., anycast addresses), if any, o the ABRO option of 6LoWPAN-ND [RFC6775], - o other ND options that happen to point to servers (such as RDNSS), o DHCPv6 options that might be defined later. In networks with more inexpensive use of multicast, the candidate IP - address may be a well-known multicast address, i.e. directory - servers are found by simply sending POST requests to that well-known + address may be a well-known multicast address, i.e. directory servers + are found by simply sending POST requests to that well-known multicast address (details TBD). As some of these sources are just (more or less educated) guesses, endpoints MUST make use of any error messages to very strictly rate- limit requests to candidate IP addresses that don't work out. E.g., an ICMP Destination Unreachable message (and, in particular, the port unreachable code for this message) may indicate the lack of a CoAP server on the candidate host, or a CoAP error response code such as 4.05 "Method Not Allowed" may indicate unwillingness of a CoAP server to act as a directory server. 5. Resource Directory Function Set This section defines the REST interfaces between an RD and endpoint servers, which is called the Resource Directory Function Set. Although the examples throughout this section assume use of CoAP [I-D.ietf-core-coap], these REST interfaces can also be realized using HTTP [RFC2616]. An RD implementing this specification MUST support the discovery, registration, update, and removal interfaces - defined in this section and MAY support the validation interface. - For the purpose of validation, an endpoint implementing this - specification SHOULD support ETag validation on /.well-known/core - (which is very straightforward for static /.well-known/core link - documents). + defined in this section. Resource directory entries are designed to be easily exported to other discovery mechanisms such as DNS-SD. For that reason, parameters that would meaningfully be mapped to DNS are limited to a maximum length of 63 bytes. 5.1. Discovery Before an endpoint can make use of an RD, it must first know the RD's IP address, port and the path of its RD Function Set. There can be @@ -425,79 +424,85 @@ ;rt="core.rd", ;rt="core.rd-lookup", ;rt="core.rd-group" 5.2. Registration After discovering the location of an RD Function Set, an endpoint MAY register its resources using the registration interface. This interface accepts a POST from an endpoint containing the list of resources to be added to the directory as the message payload in the - CoRE Link Format along with query string parameters indicating the - name of the endpoint, its domain and the lifetime of the - registration. All parameters except the endpoint name are optional. - It is expected that other specifications MAY define further - parameters (it is to be determined if a registry of parameters is - needed for this purpose). The RD then creates a new resource or - updates an existing resource in the RD and returns its location. An - endpoint MUST use that location when refreshing registrations using - this interface. Endpoint resources in the RD are kept active for the - period indicated by the lifetime parameter. The endpoint is - responsible for refreshing the entry within this period using either - the registration or update interface. The registration interface - MUST be implemented to be idempotent, so that registering twice with - the same endpoint parameter does not create multiple RD entries. + CoRE Link Format [RFC6690] or JSON Link Format + [I-D.ietf-core-links-json] along with query string parameters + indicating the name of the endpoint, its domain and the lifetime of + the registration. All parameters except the endpoint name are + optional. It is expected that other specifications MAY define + further parameters (it is to be determined if a registry of + parameters is needed for this purpose). The RD then creates a new + resource or updates an existing resource in the RD and returns its + location. An endpoint MUST use that location when refreshing + registrations using this interface. Endpoint resources in the RD are + kept active for the period indicated by the lifetime parameter. The + endpoint is responsible for refreshing the entry within this period + using either the registration or update interface. The registration + interface MUST be implemented to be idempotent, so that registering + twice with the same endpoint parameter does not create multiple RD + entries. The registration request interface is specified as follows: Interaction: EP -> RD - Method: POST URI Template: /{+rd}{?ep,d,et,lt,con} URI Template Variables: - RD Function Set path (mandatory). This is the path of the RD - Function Set. An RD SHOULD use the value "rd" for this + rd := RD Function Set path (mandatory). This is the path of the + RD Function Set. An RD SHOULD use the value "rd" for this variable whenever possible. - Endpoint (mandatory). The endpoint identifier or name of the - registering node, unique within that domain. The maximum + ep := Endpoint (mandatory). The endpoint identifier or name of + the registering node, unique within that domain. The maximum length of this parameter is 63 bytes. - Domain (optional). The domain to which this endpoint belongs. - The maximum length of this parameter is 63 bytes. Optional. - When this parameter is elided, the RD MAY associate the - endpoint with a configured default domain. + d := Domain (optional). The domain to which this endpoint + belongs. The maximum length of this parameter is 63 bytes. + Optional. When this parameter is elided, the RD MAY associate + the endpoint with a configured default domain. - Endpoint Type (optional). The semantic type of the endpoint. - The maximum length of this parameter is 63 bytes. Optional. + et := Endpoint Type (optional). The semantic type of the + endpoint. The maximum length of this parameter is 63 bytes. + Optional. - Lifetime (optional). Lifetime of the registration in seconds. - Range of 60-4294967295. If no lifetime is included, a default - value of 86400 (24 hours) SHOULD be assumed. + lt := Lifetime (optional). Lifetime of the registration in + seconds. Range of 60-4294967295. If no lifetime is included, + a default value of 86400 (24 hours) SHOULD be assumed. - Context (optional). This parameter sets the scheme, address - and port at which this server is available in the form scheme:/ - /host:port. Optional. In the absence of this parameter the - scheme of the protocol, source IP address and source port of - the register request are assumed. + con := Context (optional). This parameter sets the scheme, + address and port at which this server is available in the form + scheme://host:port. Optional. In the absence of this + parameter the scheme of the protocol, source IP address and + source port of the register request are assumed. Content-Type: application/link-format + Content-Type: application/link-format+json + The following response codes are defined for this interface: Success: 2.01 "Created". The Location header MUST be included with the new resource entry for the endpoint. This Location MUST be a stable identifier generated by the RD as it is used for all - subsequent operations on this registration (update, delete). + subsequent operations on this registration. The resource returned + in the Location is only for the purpose of the Update (PUT) and + Removal (DELETE), and MUST NOT implement GET or POST methods. Failure: 4.00 "Bad Request". Malformed request. Failure: 5.03 "Service Unavailable". Service could not perform the operation. The following example shows an endpoint with the name "node1" registering two resources to an RD using this interface. The resulting location /rd/4521 is just an example of an RD generated location. @@ -526,42 +531,42 @@ response to the first registration. An update MAY contain registration parameters if there have been changes since the last registration or update. Parameters that have not changed SHOULD NOT be included in an update. Upon receiving an update request, the RD resets the timeout for that endpoint and stores the values of the parameters included in the update (if any). The update request interface is specified as follows: Interaction: EP -> RD - Method: PUT URI Template: /{+location}{?et,lt,con} URI Template Variables: - This is the Location path returned by the RD as a result of a - successful registration. + location := This is the Location path returned by the RD as a + result of a successful registration. - Endpoint Type (optional). The semantic type of the endpoint. - The maximum length of this parameter is 63 btyes. Optional. + et := Endpoint Type (optional). The semantic type of the + endpoint. The maximum length of this parameter is 63 btyes. + Optional. - Lifetime (optional). Lifetime of the registration in seconds. - Range of 60-4294967295. If no lifetime is included, a default - value of 86400 (24 hours) SHOULD be assumed. + lt := Lifetime (optional). Lifetime of the registration in + seconds. Range of 60-4294967295. If no lifetime is included, + a default value of 86400 (24 hours) SHOULD be assumed. - Context (optional). This parameter sets the scheme, address - and port at which this server is available in the form scheme:/ - /host:port. Optional. In the absence of this parameter the - scheme of the protocol, source IP address and source port used - to register are assumed. + con := Context (optional). This parameter sets the scheme, + address and port at which this server is available in the form + scheme://host:port. Optional. In the absence of this + parameter the scheme of the protocol, source IP address and + source port used to register are assumed. Content-Type: None The following response codes are defined for this interface: Success: 2.04 "Changed" in the update was successfully processed. Failure: 4.00 "Bad Request". Malformed request. Failure: 5.03 "Service Unavailable". Service could not perform the @@ -575,66 +580,21 @@ | --- PUT /rd/4521 --------------------------> | | | | | | <-- 2.04 Changed ---------------------------- | | | Req: PUT /rd/4521 Res: 2.04 Changed -5.4. Validation - - In some cases, an RD may want to validate that it has the latest - version of an endpoint's resources. This can be performed with a GET - on the well-known interface of the CoRE Link Format including the - latest ETag stored for that endpoint. For the purpose of validation, - an endpoint implementing this specification SHOULD support ETag - validation on /.well-known/core. - - The validation request interface is specified as follows: - - Interaction: RD -> EP - - Method: GET - Path: /.well-known/core - - Parameters: None - - ETag: The ETag option MUST be included - - The following responses codes are defined for this interface: - - Success: 2.03 "Valid" in case the ETag matches - - Success: 2.05 "Content" in case the ETag does not match, the - response MUST include the most recent resource representation - (application/link-format) and its corresponding ETag. - - Failure: 4.00 "Bad Request". Malformed request. - - The following examples shows a successful validation. - - EP RD - | | - | <--- GET /.well-known/core ETag: 0x40 -------- | - | | - | | - | --- 2.03 Valid -----------------------------> | - | | - - Req: GET /.well-known/core - ETag: 0x40 - - Res: 2.03 Valid - -5.5. Removal +5.4. Removal Although RD entries have soft state and will eventually timeout after their lifetime, an endpoint SHOULD explicitly remove its entry from the RD if it knows it will no longer be available (for example on shut-down). This is accomplished using a removal interface on the RD by performing a DELETE on the endpoint resource. The removal request interface is specified as follows: Interaction: EP -> RD @@ -633,26 +593,27 @@ their lifetime, an endpoint SHOULD explicitly remove its entry from the RD if it knows it will no longer be available (for example on shut-down). This is accomplished using a removal interface on the RD by performing a DELETE on the endpoint resource. The removal request interface is specified as follows: Interaction: EP -> RD Method: DELETE + URI Template: /{+location} URI Template Variables: - This is the Location path returned by the RD as a result of a - successful registration. + location := This is the Location path returned by the RD as a + result of a successful registration. The following responses codes are defined for this interface: Success: 2.02 "Deleted" upon successful deletion Failure: 4.00 "Bad Request". Malformed request. Failure: 5.03 "Service Unavailable". Service could not perform the operation. @@ -676,61 +637,67 @@ This section defines a function set for the creation of groups of endpoints for the purpose of managing and looking up endpoints for group operations. The group function set is similar to the resource directory function set, in that a group may be created or removed. However unlike an endpoint entry, a group entry consists of a list of endpoints and does not have a lifetime associated with it. In order to make use of multicast requests with CoAP, a group MAY have a multicast address associated with it. 6.1. Register a Group + In order to create a group, a management entity used to configure groups, makes a request to the RD indicating the name of the group to create (or update), the optional domain the group belongs to, and the optional multicast address of the group. The registration message includes the list of endpoints that belong to that group. If an endpoint has already registered with the RD, the RD attempts to use the context of the endpoint from its RD endpoint entry. If the client registering the group knows the endpoint has already registered, then it MAY send a blank target URI for that endpoint - link when registering the group. + link when registering the group. Configuration of the endpoints + themselves is out of scope of this specification. Such an interface + for managing the group membership of an endpoint has been defined in + [I-D.ietf-core-groupcomm]. The registration request interface is specified as follows: Interaction: Manager -> RD Method: POST URI Template: /{+rd-group}{?gp,d,con} URI Template Variables: - RD Group Function Set path (mandatory). This is the path of - the RD Group Function Set. An RD SHOULD use the value "rd- - group" for this variable whenever possible. + rd-group := RD Group Function Set path (mandatory). This is the + path of the RD Group Function Set. An RD SHOULD use the value + "rd-group" for this variable whenever possible. - Group Name (mandatory). The name of the group to be created or - replaced, unique within that domain. The maximum length of - this parameter is 63 bytes. + gp := Group Name (mandatory). The name of the group to be + created or replaced, unique within that domain. The maximum + length of this parameter is 63 bytes. - Domain (optional). The domain to which this group belongs. + d := Domain (optional). The domain to which this group belongs. The maximum length of this parameter is 63 bytes. Optional. When this parameter is elided, the RD MAY associate the endpoint with a configured default domain. - Context (optional). This parameter is used to set the IP + con := Context (optional). This parameter is used to set the IP multicast address at which this server is available in the form scheme://multicast-address:port. Optional. In the absence of this parameter no multicast address is configured. Content-Type: application/link-format + Content-Type: application/link-format+json + The following response codes are defined for this interface: Success: 2.01 "Created". The Location header MUST be included with the new group entry. This Location MUST be a stable identifier generated by the RD as it is used for delete operations on this registration. Failure: 4.00 "Bad Request". Malformed request. Failure: 5.03 "Service Unavailable". Service could not perform the @@ -766,22 +733,22 @@ The removal request interface is specified as follows: Interaction: Manager -> RD Method: DELETE URI Template: /{+location} URI Template Variables: - This is the Location path returned by the RD as a result of a - successful group registration. + location := This is the Location path returned by the RD as a + result of a successful group registration. The following responses codes are defined for this interface: Success: 2.02 "Deleted" upon successful deletion Failure: 4.00 "Bad Request". Malformed request. Failure: 5.03 "Service Unavailable". Service could not perform the operation. @@ -820,62 +787,63 @@ parameters MUST match for a resource to be returned. The character '*' MAY be included at the end of a parameter value as a wildcard operator. The lookup interface is specified as follows: Interaction: Client -> RD Method: GET - URI Template: /{+rd-lookup-base}/{lookup- - type}{?d,ep,gp,et,rt,page,count,resource-param} + URI Template: /{+rd-lookup-base}/ + {lookup-type}{?d,ep,gp,et,rt,page,count,resource-param} Parameters: rd-lookup-base := RD Lookup Function Set path (mandatory). This - is the path of the RD Lookup Function Set. An RD SHOULD use - the value "rd-lookup" for this variable whenever possible. + is the path of the RD Lookup Function Set. An RD SHOULD use the + value "rd-lookup" for this variable whenever possible. lookup-type := ("d", "ep", "res", "gp") (mandatory) This variable is used to select the kind of lookup to perform (domain, endpoint or resource). ep := Endpoint (optional). Used for endpoint, group and resource lookups. d := Domain (optional). Used for domain, group, endpoint and resource lookups. page := Page (optional). Parameter can not be used without the - count parameter. Results are returned from result set in - pages that contains 'count' results starting from index - (page * count). + count parameter. Results are returned from result set in pages + that contains 'count' results starting from index (page * + count). count := Count (optional). Number of results is limited to this - parameter value. If the parameter is not present, then an - RD implementation specific default value SHOULD be used. + parameter value. If the parameter is not present, then an RD + implementation specific default value SHOULD be used. rt := Resource type (optional). Used for group, endpoint and resource lookups. - rt := Endpoint type (optional). Used for group, endpoint and + et := Endpoint type (optional). Used for group, endpoint and resource lookups. resource-param := Link attribute parameters (optional). Any - link attribute as defined in Section 4.1 of [RFC6690], used - for resource lookups. + link attribute as defined in Section 4.1 of [RFC6690], used for + resource lookups. The following responses codes are defined for this interface: - Success: 2.05 "Content" with an application/link-format payload - containing a matching entries for the lookup. + Success: 2.05 "Content" with an application/link-format or + application/link-format+json payload containing a matching entries + for the lookup. Failure: 4.04 "Not Found" in case no matching entry is found for a unicast request. Failure: No error response to a multicast request. Failure: 4.00 "Bad Request". Malformed request. Failure: 5.03 "Service Unavailable". Service could not perform the operation. @@ -1006,54 +976,118 @@ description MAY be exported by a resource directory to external directories. The CoRE Link Format is used for many purposes between CoAP endpoints. Some are useful mainly locally, for example checking the observability of a resource before accessing it, determining the size of a resource, or traversing dynamic resource structures. However, other links are very useful to be exported to other directories, for example the entry point resource to a functional service. -9. Security Considerations +9. DNS-SD Mapping + + TODO + +10. Security Considerations This document needs the same security considerations as described in Section 7 of [RFC5988] and Section 6 of [RFC6690]. The /.well-known/ core resource may be protected e.g. using DTLS when hosted on a CoAP server as described in [I-D.ietf-core-coap]. Access control SHOULD be performed separately for the RD Function Set and the RD Lookup Function Set, as different endpoints may be authorized to register with an RD from those authorized to lookup endpoints from the RD. Such access control SHOULD be performed in as fine-grained a level as possible. For example access control for lookups could be performed either at the domain, endpoint or resource level. -10. IANA Considerations +11. IANA Considerations + +11.1. Resource Types "core.rd", "core.rd-group" and "core.rd-lookup" resource types need to be registered with the resource type registry defined by [RFC6690]. +11.2. Link Extension + The "exp" attribute needs to be registered when a future Web Linking - attribute is created. + link-extension registry is created (e.g. in RFC5988bis). -11. Acknowledgments +11.3. RD Parameter Registry + + This specification defines a new sub-registry for registration and + lookup parameters called "RD Parameters" under "CoRE Parameters". + Although this specification defines a basic set of parameters, it is + expected that other standards that make use of this interface will + define new ones. + + Each entry in the registry must include the human readable name of + the parameter, the query parameter, validity requirements if any and + a description. The query parameter MUST be a valid URI query key + [RFC3986]. + + Initial entries in this sub-registry are as follows: + + +----------+-------+---------------+--------------------------------+ + | Name | Query | Validity | Description | + +----------+-------+---------------+--------------------------------+ + | Endpoint | ep | < 63 bytes | Name of the endpoint | + | Name | | | | + | Lifetime | lt | 60-4294967295 | Lifetime of the registration | + | | | | in seconds | + | Domain | d | < 63 bytes | Domain to which this endpoint | + | | | | belongs | + | Endpoint | et | | Semantic name of the endpoint | + | Type | | | | + | Context | con | URI | The scheme, address and port | + | | | | at which this server is | + | | | | available | + | Endpoint | ep | | Name of the endpoint, max 63 | + | Name | | | bytes | + | Group | gp | | Name of a group in the RD | + | Name | | | | + | Page | page | Integer | Used for pagination | + | Count | count | Integer | Used for pagination | + +----------+-------+---------------+--------------------------------+ + + Table 1: RD Parameters + + The IANA policy for future additions to the sub-registry is "Expert + Review" as described in [RFC5226] + +12. Acknowledgments Szymon Sasin, Kerry Lynn, Esko Dijk, Peter van der Stok, Anders Brandt, Matthieu Vial, Sampo Ukkola and Linyi Tian have provided helpful comments, discussions and ideas to improve and shape this document. The authors would also like to thank their collagues from the EU FP7 SENSEI project, where many of the resource directory concepts were originally developed. -12. Changelog +13. Changelog + + Changes from -00 to -01: + + o Removed the ETag validation feature. + + o Place holder for the DNS-SD mapping section. + + o Explicitly disabled GET or POST on returned Location. + + o New registry for RD parameters. + + o Added support for the JSON Link Format. + + o Added reference to the Groupcomm WG draft. Changes from -05 to WG Document -00: o Updated the version and date. Changes from -04 to -05: o Restricted Update to parameter updates. o Added pagination support for the Lookup interface. @@ -1099,74 +1133,94 @@ o Added the concept of an RD Domain and a registration parameter for it. o Recommended the Location returned from a registration to be stable, allowing for endpoint and Domain information to be changed during updates. o Changed the lookup interface to accept endpoint and Domain as query string parameters to control the scope of a lookup. -13. References +14. References -13.1. Normative References +14.1. Normative References + + [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. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. + [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform + Resource Identifier (URI): Generic Syntax", STD 66, + RFC 3986, January 2005. + + [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an + IANA Considerations Section in RFCs", BCP 26, RFC 5226, + May 2008. + [RFC5988] Nottingham, M., "Web Linking", RFC 5988, October 2010. [RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M., and D. Orchard, "URI Template", RFC 6570, March 2012. [RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link Format", RFC 6690, August 2012. -13.2. Informative References +14.2. Informative References [I-D.brandt-coap-subnet-discovery] Brandt, A., "Discovery of CoAP servers across subnets", draft-brandt-coap-subnet-discovery-00 (work in progress), March 2011. [I-D.ietf-core-coap] Shelby, Z., Hartke, K., and C. Bormann, "Constrained - Application Protocol (CoAP)", draft-ietf-core-coap-14 - (work in progress), March 2013. + Application Protocol (CoAP)", draft-ietf-core-coap-18 + (work in progress), June 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.vanderstok-core-bc] Stok, P. and K. Lynn, "CoAP Utilization for Building Control", draft-vanderstok-core-bc-05 (work in progress), October 2011. [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. [RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", RFC 6775, November 2012. Authors' Addresses Zach Shelby - Sensinode - Kidekuja 2 - Vuokatti 88600 + ARM + 150 Rose Orchard + San Jose 95134 FINLAND - Phone: +358407796297 - Email: zach@sensinode.com - - Srdjan Krco - Ericsson + Phone: +1-408-203-9434 + Email: zach.shelby@arm.com - Email: srdjan.krco@ericsson.com Carsten Bormann Universitaet Bremen TZI Postfach 330440 Bremen D-28359 Germany Phone: +49-421-218-63921 Email: cabo@tzi.org + + Srdjan Krco + Ericsson + + Phone: + Email: srdjan.krco@ericsson.com