Observe Notifications as CoAP Multicast Responses
draft-tiloca-core-observe-multicast-notifications-03
CoRE Working Group M. Tiloca
Internet-Draft R. Hoeglund
Updates: 7252, 7641 (if approved) RISE AB
Intended status: Standards Track C. Amsuess
Expires: January 14, 2021
F. Palombini
Ericsson AB
July 13, 2020
Observe Notifications as CoAP Multicast Responses
draft-tiloca-core-observe-multicast-notifications-03
Abstract
The Constrained Application Protocol (CoAP) allows clients to
"observe" resources at a server, and receive notifications as unicast
responses upon changes of the resource state. In some use cases,
such as based on publish-subscribe, it would be convenient for the
server to send a single notification to all the clients observing a
same target resource. This document defines how a CoAP server sends
observe notifications as response messages over multicast, by
synchronizing all the observers of a same resource on a same shared
Token value. Besides, this document defines how Group OSCORE can be
used to protect multicast notifications end-to-end from the CoAP
server to the multiple observer clients.
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 https://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 January 14, 2021.
Tiloca, et al. Expires January 14, 2021 [Page 1]
Internet-Draft Observe Multicast Notifications July 2020
Copyright Notice
Copyright (c) 2020 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
(https://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 . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Server-Side Requirements . . . . . . . . . . . . . . . . . . 5
2.1. Request . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. Informative Response . . . . . . . . . . . . . . . . . . 6
2.3. Notifications . . . . . . . . . . . . . . . . . . . . . . 8
2.4. Congestion Control . . . . . . . . . . . . . . . . . . . 9
2.5. Cancellation . . . . . . . . . . . . . . . . . . . . . . 9
2.5.1. Rough Counting of Clients in the Group Observation . 10
3. Client-Side Requirements . . . . . . . . . . . . . . . . . . 13
3.1. Request . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2. Informative Response . . . . . . . . . . . . . . . . . . 14
3.3. Notifications . . . . . . . . . . . . . . . . . . . . . . 14
3.4. Cancellation . . . . . . . . . . . . . . . . . . . . . . 15
4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5. Protection of Multicast Notifications with Group OSCORE . . . 17
5.1. Signaling the OSCORE Group in the Informative Response . 17
5.2. Server-Side Requirements . . . . . . . . . . . . . . . . 19
5.2.1. Registration . . . . . . . . . . . . . . . . . . . . 19
5.2.2. Informative Response . . . . . . . . . . . . . . . . 20
5.2.3. Notifications . . . . . . . . . . . . . . . . . . . . 20
5.2.4. Cancellation . . . . . . . . . . . . . . . . . . . . 21
5.3. Client-Side Requirements . . . . . . . . . . . . . . . . 21
5.3.1. Informative Response . . . . . . . . . . . . . . . . 21
5.3.2. Notifications . . . . . . . . . . . . . . . . . . . . 22
6. Example with Group OSCORE . . . . . . . . . . . . . . . . . . 22
7. Informative Response Parameters . . . . . . . . . . . . . . . 25
8. Security Considerations . . . . . . . . . . . . . . . . . . . 26
Show full document text