CBOR Encoding for HTTPS-based Transport for YANG Notifications

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Table of Contents

1. Introduction

This document introduces a CBOR encoding scheme for event notifications over HTTPS by using the framework proposed in [I-D.draft-ietf-netconf-https-notif-15] which supports transfer of YANG notifications over HTTPS using JSON and XML encoding schemes.¶

In [I-D.draft-ietf-netconf-https-notif-15], the capabilities HTTP-target resource allows a publisher to retrieve supported encoding formats via a GET request, while the relay-notification resource enables the publisher to send YANG notifications via POST requests. These requests and responses use different content types based on the selected encoding scheme. This document defines support for using CBOR encoding as mentioned in section 1 of [I-D.draft-ietf-netconf-https-notif-15]¶

CBOR offers an efficient and compact representation of YANG notifications.¶

Examples of the GET and POST request and reply encoded in CBOR are also provided.¶

2. Conventions and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

3. Terminology

This document uses the following terms defined in Section 2,3 and 4 of [I-D.draft-ietf-netconf-https-notif-15]:¶

• Capabilities Resource¶

• Relay-Notification¶

• Event Notification¶

The following term(s) are defined in Subscription to YANG Notifications [RFC8639]:¶

• Publisher¶

• Receiver¶

• Subscribed Notifications¶

The following term(s) are defined in Encoding of Data Modeled with YANG in the Concise Binary Object Representation (CBOR) [RFC9254]:¶

• Diagnostic Notifications¶

• YANG Schema Item iDentifier (or "YANG SID" or simply "SID"): 63-bit unsigned integer used to identify different YANG items.¶

4. CBOR Encoding of the notification(s)

YANG notifications can be encoded in CBOR using Names or SIDs in keys. Notifications encoded using names is similar to JSON encoding as defined in Section 3.4 and 4.3 of [I-D.draft-ietf-netconf-https-notif-15]. Notification encoded using YANG-SIDs replaces the names of the keys of the CBOR encoded message with a 63 bit unsigned integer. In this case, the term 'SID' is defined in Section 3.2 of [RFC9254], and the keys of the encoded data use SID value as mentioned in 4.3.2 of this document.¶

GET /some/path/capabilities HTTP/1.1
   Host: example.com
   Accept: application/cbor, application/xml;0.9, application/json;q=0.5

   HTTP/1.1 200 OK
   Date: Tue, 4 March 2025 20:33:30 GMT
   Server: example-server
   Cache-Control: no-cache
   Content-Type: application/json
   {
   "receiver-capabilities": {
     "receiver-capability": [
       "urn:ietf:capability:https-notif-receiver:encoding:json",
       "urn:ietf:capability:https-notif-receiver:encoding:xml",
       "urn:ietf:capability:https-notif-receiver:encoding:cbor"
        ]
      }
   }

A1                                      # map(1)
   75                                   # text(21)
      72656365697665722D6361706162696C6974696573 # "receiver-capabilities"
   A1                                   # map(1)
      73                                # text(19)
         72656365697665722D6361706162696C697479 # "receiver-capability"
      83                                # array(3)
         78 36                          # text(54)
            75726E3A696574663A6361706162696C6974793A68747470732D6E6F7469662D72656365697665723A656E636F64696E673A6A736F6E # "urn:ietf:capability:https-notif-receiver:encoding:json"
         78 35                          # text(53)
            75726E3A696574663A6361706162696C6974793A68747470732D6E6F7469662D72656365697665723A656E636F64696E673A786D6C # "urn:ietf:capability:https-notif-receiver:encoding:xml"
         78 36                          # text(54)
            75726E3A696574663A6361706162696C6974793A68747470732D6E6F7469662D72656365697665723A656E636F64696E673A63626F72 # "urn:ietf:capability:https-notif-receiver:encoding:cbor"

POST /some/path/relay-notification HTTP/1.1
   Host: example.com
   Content-Type: application/cbor

   {
     "ietf-https-notif:notification": {
       "eventTime": "2013-12-21T00:01:00Z",
       "example-mod:event" : {
         "event-class" : "fault",
         "reporting-entity" : { "card" : "Ethernet0" },
         "severity" : "major"
       }
     }
   }

A1                                      # map(1)
   78 1D                                # text(29)
      696574662D68747470732D6E6F7469663A6E6F74696669636174696F6E # "ietf-https-notif:notification"
   A2                                   # map(2)
      69                                # text(9)
         6576656E7454696D65             # "eventTime"
      74                                # text(20)
         323031332D31322D32315430303A30313A30305A # "2013-12-21T00:01:00Z"
      71                                # text(17)
         6578616D706C652D6D6F643A6576656E74 # "example-mod:event"
      A3                                # map(3)
         68                             # text(8)
            7365766572697479            # "severity"
         65                             # text(5)
            6D616A6F72                  # "major"
         6B                             # text(11)
            6576656E742D636C617373      # "event-class"
         65                             # text(5)
            6661756C74                  # "fault"
         70                             # text(16)
            7265706F7274696E672D656E74697479 # "reporting-entity"
         A1                             # map(1)
            64                          # text(4)
               63617264                 # "card"
            69                          # text(9)
               45746865726E657430       # "Ethernet0"

   {
    2600: {
       1: "2013-12-21T00:01:00Z",
       "example-mod:event" : {
         "event-class" : "fault",
         "reporting-entity" : { "card" : "Ethernet0" },
         "severity" : "major"
       }
     }
   }

"item": [
      {
        "namespace": "module",
        "identifier": "ietf-notification",
        "sid": "2600"
      },
      {
        "namespace": "data",
        "identifier": "/ietf-notification:notification",
        "sid": "2601"
      },
      {
        "namespace": "data",
        "identifier": "/ietf-notification:notification/eventTime",
        "sid": "2602"
      }
    ]

A1                                      # map(1)
   19 0A28                              # unsigned(2600)
   A2                                   # map(2)
      01                                # unsigned(1)
      74                                # text(20)
         323031332D31322D32315430303A30313A30305A # "2013-12-21T00:01:00Z"
      71                                # text(17)
         6578616D706C652D6D6F643A6576656E74 # "example-mod:event"
      A3                                # map(3)
         68                             # text(8)
            7365766572697479            # "severity"
         65                             # text(5)
            6D616A6F72                  # "major"
         6B                             # text(11)
            6576656E742D636C617373      # "event-class"
         65                             # text(5)
            6661756C74                  # "fault"
         70                             # text(16)
            7265706F7274696E672D656E74697479 # "reporting-entity"
         A1                             # map(1)
            64                          # text(4)
               63617264                 # "card"
            69                          # text(9)
               45746865726E657430       # "Ethernet0"

5. Scope of Experimentation

CBOR encoding may be tested against JSON and XML to evaluate requests per second, data transfer rate, and overall network efficiency.¶

Bandwidth constraints can be applied using traffic control to analyze CBOR encoding efficiency under different network conditions.¶

6. Security Considerations

Addition of the CBOR encoding introduces no specific security exposures or risks other that the ones mentioned in [RFC9254] and [I-D.draft-ietf-netconf-https-notif-15] (An HTTPS-based Transport for YANG Notifications)¶

7. IANA Considerations

This document requests the the IANA registry to include an additional entry to the proposed initial assignments in the “Capabilities for HTTPS Notification Receivers” registry within the YANG Notifications registry group(defined in [RFC3553]) as requested in the draft [I-D.ietf-netconf-http-client-server]. The following entry is added :¶

Record:
   URN:         urn:ietf:params:yang-notif:https-capability:encoding:cbor
   Reference:   RFC XXXX:An HTTPS-based Transport for YANG Notifications
   Description: Identifies support for CBOR-encoded notifications.

8. References

Acknowledgments

The authors acknowlegde the support of Kent Watsen and Mahesh Jethanandani, the authors of [I-D.draft-ietf-netconf-https-notif-15] for their guidance and support provided to draft this document.¶

Authors' Addresses