Specification

• https://openconnectivity.org/developer/specifications

Terminology

• ACL: Access Control List
• SACL: Signed Access Control List
• ACE: Access Control Entry
• SRM: Secure Resource Manager
• BS: Bootstrap Server
• BC: Bootstrapping Credential
• BP: Bootstrapping Parameters
• icv: Spec version of the core specification this device is implemented to. (e.g. ocf.1.1.0)
• dmv: Data Model Version. Spec version of the Resource Specification to which this device data model is implemented. (e.g. ocf.res.1.0.0, ocf.sh.1.0.0)
• OTM: Ownership Transfer Methods
• doxm: Device Owner Transfer Method
• OBT: Onboarding Tool
• RD: Resource Directory
• rt: Resource Type
• if: Interface
• p: Policy
• bm: bitmask corresponds to a specific Policyt rule.
  • Bit 0 (discoverable flag)
  • Bit 1 (observable flag)
• di: Device ID
• wk: Wellknown
• RAML: RESTful API Modeling Language
• SSV: String with Space Separated Values
• BSP: Blank(i.e. space) separated list of values encoded within a string.
• CSV: Comma separated list of values encoded within a string.

Interfaces

• oic.if.baseline (baseline) - RETRIEVE, UPDATE
• oic.if.ll (links list) - RETRIEVE
• oic.if.b (batch) - RETRIEVE, UPDATE
• oic.if.r (read-only) - RETRIEVE
• oic.if.rw (read-write) - RETRIEVE, UPDATE
• oic.if.a (actuator)- CREATE, RETRIEVE, UPDATE
• oic.if.s (sensor) - RETRIEVE

Mapping of CRUDN to CoAP

• RETRIEVE: GET
• CREATE: POST or PUT
• UPDATE: POST
• DELETE: DELETE

CoAP over TCP

• KeepAlive
  • '/oic/ping' (rt=oic.wk.ping, if=oic.if.rw) - Ping
    • prop: 'in' (integer) - Interval

Versioning

• Versioning is implemented through the "CoAP Options"
• CoAP Content-Formats (RFC7252 Section 12.3 Table 9)
  • ID 0: text/plain
  • ID 50: application/json
  • ID 60: application/cbor
  • ID 10000: application/vnd.ocf+cbor
  • Content-Format ID policy (RFC7252 Section 12.3 Table 10)
    • 0~255: Expert Review
    • 256~9999: IETF Review or IESG Approval
    • 10000~64999: First Come First Served
    • 65000~65535: Experimental use (no operational use)
• CoAP Option Numbers (RFC7252 Section 5.10 Table 4)
  • Number 12: "Content-Format", Format=uint, Length=2bytes
  • Number 17: "Accept", Format=uint, Length=2bytes
  • Number 2049: "Accept Version", Format=uint, Length=2bytes
  • Number 2053: "Content-Format Version", Format=uint, Length=2bytes
  • Option Number policy (RFC7252 Section 12.2 Table 8)
    • 0~255: IETF Review or IESG Approval
    • 256~2047: Specification Required
    • 2048~64999: Expert Review
    • 65000~65535: Experimental use (no operational use)
    • Odd numbers indicate a critical option, while even numbers indicate an elective option.
• Version Representation (uint, Length=2bytes(16bits))
  • Major:Minor:Sub = 5:5:6
  • OCF 1.0.0 = 0b00001 00000 000000 = 0x0800 = 2048
  • OCF 1.1.0 = 0b00001 00001 000000 = 0x0840 = 2112

Use case

• OK: OIC 1.1 Client <----> OIC 1.1 Server
  • GET /oic/res with application/cbor
    • Accept (17) = 60
  • Response /oic/res per OIC 1.1
    • Content-Format (12) = 60
• OK: OIC 1.1 Clinet <----> OCF 1.0 Server
  • GET /oic/res with application/cbor
    • Accept (17) = 60
  • Response /oic/res per OIC 1.1
    • Content-Format (12) = 60
• OK: OCF 1.0 Client <----> OCF 1.0 Server
  • GET /oic/res with application/vnd.ocf+cbor
    • Accept (17) = 10000
    • Accept-Version (2049) = 2048 (OCF 1.0.0)
  • Response /oic/res per OCF 1.0
    • Content-Format (12) = 10000
    • Content-Format Version (2053) = 2048 (OCF 1.0.0)
• retry with fallback case
  • Try 1) OCF 1.0 Client <----> OIC 1.1 Server
    • GET /oic/res with application/vnd.ocf+cbor
      • Accept (17) = 10000
      • Accept-Version (2049) = 2048 (OCF 1.0.0)
    • Response with error
      • (error code ???)
  • Try 2) OCF 1.0 Client <----> OIC 1.1 Server
    • GET /oic/res with application/cbor
      • Accept (17) = 60
    • Response with OIC 1.1
      • Content-Format (12) = 60