Information technology — Open Connectivity Foundation (OCF) Specification — Part 3: Bridging specification

This document specifies a framework for translation between OCF Devices and other ecosystems, and specifies the behaviour of a Bridging Function that exposes servers in non-OCF ecosystem to OCF Clients and/or exposes OCF Servers to clients in non-OCF ecosystem. Translation per specific Device is left to other documents (deep translation). This document provides generic requirements that apply unless overridden by a more specific document.

Technologies de l'information — Specification de la Fondation pour la connectivité ouverte (Fondation OCF) — Partie 3: Spécification de pontage

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Published
Publication Date
17-Oct-2021
Current Stage
6060 - International Standard published
Start Date
18-Oct-2021
Due Date
16-May-2022
Completion Date
18-Oct-2021
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INTERNATIONAL ISO/IEC
STANDARD 30118-3
Second edition
2021-10
Information technology — Open
Connectivity Foundation (OCF)
Specification —
Part 3:
Bridging specification
Technologies de l'information — Specification de la Fondation pour la
connectivité ouverte (Fondation OCF) —
Partie 3: Spécification de pontage
Reference number
ISO/IEC 30118-3:2021(E)
© ISO/IEC 2021

---------------------- Page: 1 ----------------------
ISO/IEC 30118-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
  © ISO/IEC 2021 – All rights reserved

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ISO/IEC 30118-3:2021(E)
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviated terms . 4
4 Document conventions and organization . 4
4.1 Conventions . 4
4.2 Notation . 4
5 Introduction . 5
5.1 Translation between OCF and non-OCF ecosystem - primitive concept of
Bridging . 5
5.2 Bridge platform . 5
5.3 Symmetric vs. asymmetric bridging . 7
5.4 General requirements . 8
5.4.1 Requirements common to all bridge platforms . 8
5.4.2 Requirements specific to symmetric bridge platforms . 8
5.5 VOD list . 9
5.6 Resource discovery . 9
5.7 "Deep translation" vs. "on-the-fly" . 14
5.8 Security . 14
6 Device type definitions . 14
7 Resource type definitions . 14
7.1 List of resource types . 14
7.2 VOD list . 15
7.2.1 Introduction . 15
7.2.2 Example URI . 15
7.2.3 Resource type . 15
7.2.4 OpenAPI 2.0 definition . 15
7.2.5 Property definition . 17
7.2.6 CRUDN behaviour . 17

© ISO/IEC 2021 – All rights reserved iii

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ISO/IEC 30118-3:2021(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees established
by the respective organization to deal with particular fields of technical activity. ISO and IEC technical
committees collaborate in fields of mutual interest. Other international organizations, governmental and non-
governmental, in liaison with ISO and IEC, also take part in the work.
The procedures used to develop this document and those intended for its further maintenance are described in
the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
document should be noted (see www.iso.org/directives or www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on the ISO list
of patent declarations received (see www.iso.org/patents) or the IEC list of patent declarations received
(see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not constitute
an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see  www.iso.org/iso/foreword.html. In
the IEC, see www.iec.ch/understanding-standards.
This document was prepared by the Open Connectivity Foundation (OCF) (as OCF Bridging Framework
Specification, version 2.2.0) and drafted in accordance with its editorial rules. It was adopted, under the JTC 1
PAS procedure, by Joint Technical Committee ISO/IEC JTC 1, Information technology.
This second edition cancels and replaces the first edition (ISO/IEC 30118-3:2018), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— bridging specification has been made more generic;
— text moved from AllJoyn mapping to the resource to Resource to AllJoyn interface mapping specification;
— addition of clarifications throughout.
A list of all parts in the ISO/IEC 30118 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html and www.iec.ch/national-
committees.

iv © ISO/IEC 2021 – All rights reserved

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ISO/IEC 30118-3:2021(E)
Introduction
This document, and all the other parts associated with this document, were developed in response to
worldwide demand for smart home focused Internet of Things (IoT) devices, such as appliances, door
locks, security cameras, sensors, and actuators; these to be modelled and securely controlled, locally
and remotely, over an IP network.
While some inter-device communication existed, no universal language had been developed for the
IoT. Device makers instead had to choose between disparate frameworks, limiting their market share,
or developing across multiple ecosystems, increasing their costs. The burden then falls on end users
to determine whether the products they want are compatible with the ecosystem they bought into, or
find ways to integrate their devices into their network, and try to solve interoperability issues on their
own.
In addition to the smart home, IoT deployments in commercial environments are hampered by a lack
of security. This issue can be avoided by having a secure IoT communication framework, which this
standard solves.
The goal of these documents is then to connect the next 25 billion devices for the IoT, providing secure
and reliable device discovery and connectivity across multiple OSs and platforms. There are multiple
proposals and forums driving different approaches, but no single solution addresses the majority of
key requirements. This document and the associated parts enable industry consolidation around a
common, secure, interoperable approach.
ISO/IEC 30118 consists of eighteen parts, under the general title Information technology — Open
Connectivity Foundation (OCF) Specification. The parts fall into logical groupings as described herein:
– Core framework
– Part 1: Core Specification
– Part 2: Security Specification
– Part 13: Onboarding Tool Specification
– Bridging framework and bridges
– Part 3: Bridging Specification
– Part 6: Resource to Alljoyn Interface Mapping Specification
– Part 8: OCF Resource to oneM2M Resource Mapping Specification
– Part 14: OCF Resource to BLE Mapping Specification
– Part 15: OCF Resource to EnOcean Mapping Specification
– Part 16: OCF Resource to UPlus Mapping Specification
– Part 17: OCF Resource to Zigbee Cluster Mapping Specification
– Part 18: OCF Resource to Z-Wave Mapping Specification
– Resource and Device models
– Part 4: Resource Type Specification
– Part 5: Device Specification
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ISO/IEC 30118-3:2021(E)
– Core framework extensions
– Part 7: Wi-Fi Easy Setup Specification
– Part 9: Core Optional Specification
– OCF Cloud
– Part 10: Cloud API for Cloud Services Specification
– Part 11: Device to Cloud Services Specification
– Part 12: Cloud Security Specification
vi © ISO/IEC 2021 – All rights reserved

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INTERNATIONAL STANDARD ISO/IEC 30118-3:2021(E)

Information technology — Open Connectivity
Foundation (OCF) Specification —
Part 3:
Bridging specification
1 Scope
This document specifies a framework for translation between OCF Devices and other ecosystems, and
specifies the behaviour of a Bridging Function that exposes servers in non-OCF ecosystem to OCF
Clients and/or exposes OCF Servers to clients in non-OCF ecosystem. Translation per specific Device
is left to other documents (deep translation). This document provides generic requirements that apply
unless overridden by a more specific document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 30118-1 Information technology -- Open Connectivity Foundation (OCF) Specification -- Part 1:
Core specification
https://www.iso.org/standard/53238.html
ISO/IEC 30118-2 Information technology -- Open Connectivity Foundation (OCF) Specification -- Part 2:
Security specification
https://www.iso.org/standard/74239.html
JSON Schema Core, JSON Schema: core definitions and terminology, January 2013
http://json-schema.org/latest/json-schema-core.html
OpenAPI Specification, Version 2.0
https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 30118-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
– ISO Online browsing platform: available at https://www.iso.org/obp
– IEC Electropedia: available at http://www.electropedia.org/
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ISO/IEC 30118-3:2021(E)
3.1.1
Asymmetric Client Bridge
Bridge (3.1.3) that exposes another ecosystem's clients into the OCF ecosystem as Virtual OCF Clients
(3.1.21). This is equivalent to exposing OCF Servers (3.1.18) into the other ecosystem.
3.1.2
Asymmetric Server Bridge
Bridge that exposes another ecosystem devices into the OCF ecosystem as Virtual OCF Servers
(3.1.18). How this is handled in each ecosystem is specified on a per ecosystem basis in this document.
3.1.3
Bridge
OCF Device that has a Device Type of "oic.d.bridge", provides information on the set of Virtual OCF
Devices (3.1.22) that are resident on the same Bridge Platform.
3.1.4
Bridge Platform
entity on which the Bridge (3.1.3) and Virtual OCF Devices (3.1.22) are resident
3.1.5
Bridged Client
logical entity that accesses data via a Bridged Protocol (3.1.7)
3.1.6
Bridged Device
Bridged Client (3.1.5) or Bridged Server (3.1.10).
3.1.7
Bridged Protocol
another protocol that is being translated to or from OCF protocols
3.1.8
Bridged Resource
artefact modelled and exposed by a Bridged Protocol (3.1.7)
3.1.9
Bridged Resource Type
schema used with a Bridged Protocol (3.1.7)
3.1.10
Bridged Server
logical entity that provides data via a Bridged Protocol (3.1.7). More than one Bridged Server can exist
on the same physical platform.
3.1.11
Bridging Function
logic resident on the Bridge Platform (3.1.4) that performs that protocol mapping between OCF and
the Bridged Protocol (3.1.7); a Bridge Platform (3.1.4) may contain multiple Bridging Functions
dependent on the number of Bridged Protocols (3.1.7) supported.
3.1.12
OCF Bridge Device
OCF Device (3.1.14) that can represent devices that exist on the network but communicate using a
Bridged Protocol (3.1.7) rather than OCF protocols.
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ISO/IEC 30118-3:2021(E)
3.1.13
OCF Client
logical entity that accesses an OCF Resource (3.1.15) on an OCF Server (3.1.18), which might be a
Virtual OCF Server (3.1.24) exposed by the OCF Bridge Device (3.1.12)
3.1.14
OCF Device
logical entity that assumes one or more OCF. More than one OCF Device can exist on the same
physical platform
3.1.15
OCF Resource
represents an artefact modelled and exposed by the OCF Framework
3.1.16
OCF Resource Property
significant aspect or notion including metadata that is exposed through the OCF Resource (3.1.15)
3.1.17
OCF Resource Type
OCF Resource Property (3.1.16) that represents the data type definition for the OCF Resource (3.1.15)
3.1.18
OCF Server
logical entity with the role of providing resource state information and allowing remote control of its
resources
3.1.19
Virtual Bridged Client
logical representation of an OCF Client (3.1.13), which an OCF Bridge Device (3.1.12) exposes to
Bridged Servers (3.1.10).
3.1.20
Virtual Bridged Server
logical representation of an OCF Server (3.1.18), which an OCF Bridge Device (3.1.12) exposes to
Bridged Clients (3.1.5).
3.1.21
Virtual OCF Client
logical representation of a Bridged Client (3.1.5), which an OCF Bridge Device (3.1.12) exposes to
OCF Servers (3.1.18)
3.1.22
Virtual OCF Device
Virtual OCF Client (3.1.21) or Virtual OCF Server (3.1.24).
3.1.23
Virtual OCF Resource
logical representation of a Bridged Resource (3.1.8), which an OCF Bridge Device (3.1.12) exposes to
OCF Clients (3.1.13)
3.1.24
Virtual OCF Server
logical representation of a Bridged Server (3.1.10), which an OCF Bridge Device (3.1.12) exposes to
OCF Clients (3.1.13).
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ISO/IEC 30118-3:2021(E)
3.2 Symbols and abbreviated terms
CRUDN Create, Read, Update, Delete, and Notify
4 Document conventions and organization
4.1 Conventions
In this document a number of terms, conditions, mechanisms, sequences, parameters, events, states,
or similar terms are printed with the first letter of each word in uppercase and the rest lowercase (e.g.,
Network Architecture). Any lowercase uses of these words have the normal technical English meaning.
In this document, to be consistent with the IETF usages for RESTful operations, the RESTful operation
words CRUDN, CREATE, RETRIVE, UPDATE, DELETE, and NOTIFY will have all letters capitalized.
Any lowercase uses of these words have the normal technical English meaning.
4.2 Notation
In this document, features are described as required, recommended, allowed or DEPRECATED as
follows:
Required (or shall or mandatory).
– These basic features shall be implemented to comply with this document. The phrases “shall not”,
and "PROHIBITED" indicate behaviour that is prohibited, i.e. that if performed means the
implementation is not in compliance.
Recommended (or should).
– These features add functionality supported by this document and should be implemented.
Recommended features take advantage of the capabilities of this document, usually without
imposing major increase of complexity. Notice that for compliance testing, if a recommended
feature is implemented, it shall meet the specified requirements to be in compliance with these
guidelines. Some recommended features could become requirements in the future. The phrase
"should not" indicates behaviour that is permitted but not recommended.
Allowed (or allowed).
– These features are neither required nor recommended by this document, but if the feature is
implemented, it shall meet the specified requirements to be in compliance with these guidelines.
– Conditionally allowed (CA)The definition or behaviour depends on a condition. If the specified
condition is met, then the definition or behaviour is allowed, otherwise it is not allowed.
Conditionally required (CR)
– The definition or behaviour depends on a condition. If the specified condition is met, then the
definition or behaviour is required. Otherwise the definition or behaviour is allowed as default
unless specifically defined as not allowed.
DEPRECATED
– Although these features are still described in this document, they should not be implemented except
for backward compatibility. The occurrence of a deprecated feature during operation of an
implementation compliant with the current document has no effect on the implementation’s
operation and does not produce any error conditions. Backward compatibility may require that a
feature is implemented and functions as specified but it shall never be used by implementations
compliant with this document.
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ISO/IEC 30118-3:2021(E)
Strings that are to be taken literally are enclosed in "double quotes".
Words that are emphasized are printed in italic.
5 Introduction
5.1 Translation between OCF and non-OCF ecosystem - primitive concept of
Bridging
The details of Bridging may be implemented in many ways, for example, by using a Bridge Platform
with an entity handler to interface directly to a Non-OCF device as shown in Figure 1.
OCF
Heart Rate
Non-OCF
Device
Bridge Platform Sensor
Protocol
(as Client)
Device
Non-OCF ecosystem

Figure 1 – Server bridging to Non- OCF device
On start-up the Bridge Platform runs the entity handlers which discover the non-OCF systems (e.g.,
Heart Rate Sensor Device) and create Resources for each Device or functionality discovered. The
entity handler creates a Resource for each discovered Device or functionality and binds itself to that
Resource. These Resources are made discoverable by the Bridge Platform.
Once the Resources are created and made discoverable, then the Client Device can discover these
Resources and operate on them using the mechanisms described in ISO/IEC 30118-1. The requests
to a Resource on the Bridge Platform are then interpreted by the entity handler and forwarded to the
non-OCF device using the protocol supported by the non-OCF device. The returned information from
the non-OCF device is then mapped to the appropriate response for that Resource.
Current OCF Bridging architecture implements the entity handler in the form of VOD.
5.2 Bridge platform
This clause describes the functionality of a Bridge Platform; such a device is illustrated in Figure 2.
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Bridging Function
ISO/IEC 30118-3:2021(E)
Bridge Platform
Bridge
Virtual Virtual
OCF Bridged
OCF Bridged
OCF Bridged
Protocol Protocol
Server Client
Client Server
Virtual Virtual
OCF Bridged
OCF Bridged
OCF Bridged
Protocol Protocol
Client Server
Server Client

Figure 2 – Bridge Platform components
A Bridge Platform enables the representation of one or more Bridged Devices as Virtual OCF Devices
(VODs) on the network and/or enables the representation of one or more OCF Devices as Virtual OCF
Devices using another protocol on the network. The Bridged Devices themselves are out of the scope
of this document. The only difference between a native OCF Device and a VOD from the perspective
of an OCF Client is the inclusion of "oic.d.virtual" in the "rt" of "/oic/d" of the VOD.
A Bridge Platform exposes a Bridge Device which is an OCF Device with a Device Type of
"oic.d.bridge". This provides to an OCF Client an explicit indication that the discovered Device is
performing a bridging function. This is useful for several reasons; 1) when establishing a home network,
the Client can determine that the bridge is reachable and functional when no bridged devices are
present, 2) allows for specific actions to be performed on the bridge considering the known functionality
a bridge supports, 3) allows for explicit discovery of all devices that are serving a bridging function
which benefits trouble shooting and maintenance actions on behalf of a user. When such a device is
discovered the exposed Resources on the OCF Bridge Device describe other devices. For example,
as shown in Figure 3.
OCF facing
Bridged Devices
Bridge Platform
Fan
Virtual OCF Server 1
(oic.d.fan)
Virtual OCF Server 2
Light 1
(oic.d.light)
Virtual OCF Server 3
(oic.d.light)
Light 2

Figure 3 – Schematic overview of a Bridge Platform bridging non-OCF devices
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Bridging Function
ISO/IEC 30118-3:2021(E)
It is expected that the Bridge Platform creates a set of devices during the start-up of the Bridge Platform,
these being the Bridge and any known VODs. The exposed set of VODs can change as Bridged
Devices are added or removed from the bridge. The adding and removing of Bridged Devices is
implementation dependent.
5.3 Symmetric vs. asymmetric bridging
There are two kinds of bridging: symmetric and asymmetric. In symmetric bridging, a bridge device
exposes OCF server(s) to another ecosystem and exposes other ecosystem’s server(s) to OCF. In
asymmetric bridging, a bridge device exposes OCF server(s) to another ecosystem or exposes another
ecosystem’s server(s) to OCF, but not both. The former case is called an Asymmetric Server Bridge
(see Figure 4), the latter case is called an Asymmetric Client Bridge (see Figure 5)
Bridge Platform
Bridged
Bridged
Server #1
OCF
OCF Virtual OCF
Protocol
Protocol Server #1
Client #1
Virtual
OCF
Bridged
Protocol
Client(s)
Virtual OCF
OCF
OCF
Bridged
Server #2
Protocol
Bridged
Protocol
Client #2
Server #2
Not in scope
of OCF Bridging spec

Figure 4 – Asymmetric server bridge
In Figure 4 each Bridged Server is exposed as a Virtual OCF Server to OCF side. These Virtual OCF
Servers are same as normal OCF Servers except that they have additional rt value ("oic.d.virtual") for
"/oic/d". The details of the Virtual Bridged Client are not in scope of this document.
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Bridging Function
ISO/IEC 30118-3:2021(E)
Bridge Platform
Bridged Client #1
(Read-Write Server #1)
Virtual OCF Client
OCF
(Aligned to:
Server #1
RW ACL on Server #1)
Virtual
Bridged Client #2
Bridged
(Read-Write Server #1)
Server(s)
Virtual OCF Client
(Aligned to:
OCF
RO ACL on Server #1,
Server #2
RW ACL on Server #2)
Bridged Client #3
(Read-Only Server #1)
Not in scope
of OCF Bridging spec

Figure 5 – Asymmetric client bridge
Figure 5 shows that each access to the OCF Server is modelled as a Virtual OCF Client. Those
accesses can be aggregated if their target OCF servers and access permissions are same, therefore
a Virtual OCF Client can tackle multiple Bridged Clients.
5.4 General requirements
5.4.1 Requirements common to all bridge platforms
A VOD shall have a Device Type that contains "oic.d.virtual". This allows Bridge Platforms to determine
if a device is already being translated when multiple Bridge Platforms are present or Clients to
determine if corresponding Server is a VOD or not.
Each Bridged Device shall be exposed as a separate Virtual OCF Server or Client, with its own OCF
Endpoint, and set of mandatory Resources (as defined in ISO/IEC 30118-1 and ISO/IEC 30118-2).
Discovery of a VOD is the same as for an ordinary OCF Device; that is the VOD shall respond to
multicast discovery requests. This allows platform-specific, device-specific, and resource-specific
fields to all be preserved across translation.
The Bridge Introspection Device Data (IDD) provides information for the Resources exposed by the
Bridge only. Each VOD shall expose an instance of "oic.wk.introspection" which provides a URL to an
IDD for the specific VOD.
5.4.2 Requirements specific to symmetric bridge platforms
In addition to the requirements mentioned in 5.4.1, Symmetric Bridging shall satisfy following
requirements.
The Bridge Platform shall check the protocol-independent UUID ("piid" in OCF) of each device and
shall not advertise back into a Bridged Protocol a device originally seen via that Bridged Protocol. The
Bridge Platform shall stop translating any Bridged Protocol device exposed in OCF via another Bridge
Platform if the Bridge Platform sees the device via the Bridged Protocol. Similarly, the Bridge Platform
shall not advertise an OCF Device back into OCF, and the Bridge Platform shall stop translating any
OCF device exposed in the Bridged Protocol via another Bridge Platform if the Bridge Platform sees
the device via OCF. These require that the Bridge Platform can determine when a device is already
being translated. A VOD shall be indicated on the OCF Security Domain with a Device Type of
"oic.d.virtual".
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ISO/IEC 30118-3:2021(E)
The Bridge Platform shall detect duplicate VODs (with the same protocol-independent UUID) present
in a network and shall not create more than one corresponding virtual device as it translates those
duplicate devices into another network.
5.5 VOD list
For maintenance purposes, the Bridge maintains a list of VODs. This list includes Virtual OCF Servers
and Virtual OCF Clients created by the Bridge Platform and subsequently on-boarded, as specified in
ISO/IEC 30118-2. A single instance of the Resource Type that defines the VOD list (see clause 7.2)
shall be exposed by the Bridge. Please refer to ISO/IEC 30118-2 for detailed operational requirements
for the VOD list.
5.6 Resource discovery
A Bridge Platform shall detect devices that arrive and leave the Bridged network or the OCF Security
Domain. Where there is no pre-existing mechanism to reliably detect the arrival and departure of
devices on a network, a Bridge Platform shall periodically poll the network to detect the arrival and
departure of devices, for example using COAP multicast discovery (a multicast RETRIEVE of "/oic/res")
in the case of the OCF Security Domain. Bridge Platform implementations are encouraged to use a
poll interval of 30 seconds plus or minus a random delay of a few seconds.
A Bridge Platform and any exposed VODs shall each respond to network discovery commands. The
response to a RETRIEVE on "/oic/res" shall only include the devices that match the RETRIEVE request.
For example, if a Bridge exposes VODs for the fan and lights shown in Figure 3, and an OCF Client
performs a discovery request with a content format of "application/vnd.ocf+cbor", there will be four
discrete respon
...

INTERNATIONAL ISO/IEC
STANDARD 30118-3
Second edition
Information technology — Open
Connectivity Foundation (OCF)
Specification —
Part 3:
Bridging specification
Technologies de l'information — Spécification de la Fondation pour la
connectivité ouverte (Fondation OCF) —
Partie 3: Spécification de pontage
PROOF/ÉPREUVE
Reference number
ISO/IEC 30118-3:2021(E)
©
ISO/IEC 2021

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ISO/IEC 30118-3:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved

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ISO/IEC 30118-3:2021(E)
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviated terms . 4
4 Document conventions and organization . 4
4.1 Conventions . 4
4.2 Notation . 4
5 Introduction . 5
5.1 Translation between OCF and non-OCF ecosystem - primitive concept of
Bridging . 5
5.2 Bridge platform . 5
5.3 Symmetric vs. asymmetric bridging . 7
5.4 General requirements . 8
5.4.1 Requirements common to all bridge platforms . 8
5.4.2 Requirements specific to symmetric bridge platforms . 8
5.5 VOD list . 9
5.6 Resource discovery . 9
5.7 "Deep translation" vs. "on-the-fly" . 14
5.8 Security . 14
6 Device type definitions . 14
7 Resource type definitions . 14
7.1 List of resource types . 14
7.2 VOD list . 15
7.2.1 Introduction . 15
7.2.2 Example URI . 15
7.2.3 Resource type . 15
7.2.4 OpenAPI 2.0 definition . 15
7.2.5 Property definition . 17
7.2.6 CRUDN behaviour . 17

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ISO/IEC 30118-3:2021(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees established
by the respective organization to deal with particular fields of technical activity. ISO and IEC technical
committees collaborate in fields of mutual interest. Other international organizations, governmental and non-
governmental, in liaison with ISO and IEC, also take part in the work.
The procedures used to develop this document and those intended for its further maintenance are described in
the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of document should be noted (see www.iso.org/directives or www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on the ISO list
of patent declarations received (see www.iso.org/patents) or the IEC list of patent declarations received
(see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not constitute
an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see  www.iso.org/iso/foreword.html.
In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by the Open Connectivity Foundation (OCF) (as OCF Bridging Framework
Specification, version 2.2.0) and drafted in accordance with its editorial rules. It was adopted, under the JTC 1
PAS procedure, by Joint Technical Committee ISO/IEC JTC 1, Information technology.
This second edition cancels and replaces the first edition (ISO/IEC 30118-3:2018), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— renaming of smarthome to generic applicable device specification;
— addition of various new resources;
— addition of clarifications throughout.
A list of all parts in the ISO/IEC 30118 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards body.
A complete listing of these bodies can be found at www.iso.org/members.html and www.iec.ch/
national-committees.
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ISO/IEC 30118-3:2021(E)
Introduction
This document, and all the other parts associated with this document, were developed in response to
worldwide demand for smart home focused Internet of Things (IoT) devices, such as appliances, door
locks, security cameras, sensors, and actuators; these to be modelled and securely controlled, locally
and remotely, over an IP network.
While some inter-device communication existed, no universal language had been developed for the
IoT. Device makers instead had to choose between disparate frameworks, limiting their market share,
or developing across multiple ecosystems, increasing their costs. The burden then falls on end users
to determine whether the products they want are compatible with the ecosystem they bought into, or
find ways to integrate their devices into their network, and try to solve interoperability issues on their
own.
In addition to the smart home, IoT deployments in commercial environments are hampered by a lack
of security. This issue can be avoided by having a secure IoT communication framework, which this
standard solves.
The goal of these documents is then to connect the next 25 billion devices for the IoT, providing secure
and reliable device discovery and connectivity across multiple OSs and platforms. There are multiple
proposals and forums driving different approaches, but no single solution addresses the majority of
key requirements. This document and the associated parts enable industry consolidation around a
common, secure, interoperable approach.
ISO/IEC 30118 consists of eighteen parts, under the general title Information technology — Open
Connectivity Foundation (OCF) Specification. The parts fall into logical groupings as described herein:
– Core framework
– Part 1: Core Specification
– Part 2: Security Specification
– Part 13: Onboarding Tool Specification
– Bridging framework and bridges
– Part 3: Bridging Specification
– Part 6: Resource to Alljoyn Interface Mapping Specification
– Part 8: OCF Resource to oneM2M Resource Mapping Specification
– Part 14: OCF Resource to BLE Mapping Specification
– Part 15: OCF Resource to EnOcean Mapping Specification
– Part 16: OCF Resource to UPlus Mapping Specification
– Part 17: OCF Resource to Zigbee Cluster Mapping Specification
– Part 18: OCF Resource to Z-Wave Mapping Specification
– Resource and Device models
– Part 4: Resource Type Specification
– Part 5: Device Specification
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ISO/IEC 30118-3:2021(E)
– Core framework extensions
– Part 7: Wi-Fi Easy Setup Specification
– Part 9: Core Optional Specification
– OCF Cloud
– Part 10: Cloud API for Cloud Services Specification
– Part 11: Device to Cloud Services Specification
– Part 12: Cloud Security Specification
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INTERNATIONAL STANDARD ISO/IEC 30118-3:2021(E)
Information technology — Open Connectivity
Foundation (OCF) —
Part 3:
Bridging specification
1 Scope
This document specifies a framework for translation between OCF Devices and other ecosystems, and
specifies the behaviour of a Bridging Function that exposes servers in non-OCF ecosystem to OCF
Clients and/or exposes OCF Servers to clients in non-OCF ecosystem. Translation per specific Device
is left to other documents (deep translation). This document provides generic requirements that apply
unless overridden by a more specific document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 30118-1 Information technology -- Open Connectivity Foundation (OCF) Specification -- Part 1:
Core specification
https://www.iso.org/standard/53238.html
ISO/IEC 30118-2 Information technology -- Open Connectivity Foundation (OCF) Specification -- Part 2:
Security specification
https://www.iso.org/standard/74239.html
JSON Schema Core, JSON Schema: core definitions and terminology, January 2013
http://json-schema.org/latest/json-schema-core.html
OpenAPI Specification, Version 2.0
https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 30118-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
– ISO Online browsing platform: available at https://www.iso.org/obp
– IEC Electropedia: available at http://www.electropedia.org/
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ISO/IEC 30118-3:2021(E)
3.1.1
Asymmetric Client Bridge
Bridge (3.1.3) that exposes another ecosystem's clients into the OCF ecosystem as Virtual OCF Clients
(3.1.21). This is equivalent to exposing OCF Servers (3.1.18) into the other ecosystem.
3.1.2
Asymmetric Server Bridge
Bridge that exposes another ecosystem devices into the OCF ecosystem as Virtual OCF Servers
(3.1.18). How this is handled in each ecosystem is specified on a per ecosystem basis in this document.
3.1.3
Bridge
OCF Device that has a Device Type of "oic.d.bridge", provides information on the set of Virtual OCF
Devices (3.1.22) that are resident on the same Bridge Platform.
3.1.4
Bridge Platform
entity on which the Bridge (3.1.3) and Virtual OCF Devices (3.1.22) are resident
3.1.5
Bridged Client
logical entity that accesses data via a Bridged Protocol (3.1.7)
3.1.6
Bridged Device
Bridged Client (3.1.5) or Bridged Server (3.1.10).
3.1.7
Bridged Protocol
another protocol that is being translated to or from OCF protocols
3.1.8
Bridged Resource
artefact modelled and exposed by a Bridged Protocol (3.1.7)
3.1.9
Bridged Resource Type
schema used with a Bridged Protocol (3.1.7)
3.1.10
Bridged Server
logical entity that provides data via a Bridged Protocol (3.1.7). More than one Bridged Server can exist
on the same physical platform.
3.1.11
Bridging Function
logic resident on the Bridge Platform (3.1.4) that performs that protocol mapping between OCF and
the Bridged Protocol (3.1.7); a Bridge Platform (3.1.4) may contain multiple Bridging Functions
dependent on the number of Bridged Protocols (3.1.7) supported.
3.1.12
OCF Bridge Device
OCF Device (3.1.14) that can represent devices that exist on the network but communicate using a
Bridged Protocol (3.1.7) rather than OCF protocols.
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ISO/IEC 30118-3:2021(E)
3.1.13
OCF Client
logical entity that accesses an OCF Resource (3.1.15) on an OCF Server (3.1.18), which might be a
Virtual OCF Server (3.1.24) exposed by the OCF Bridge Device (3.1.12)
3.1.14
OCF Device
logical entity that assumes one or more OCF. More than one OCF Device can exist on the same
physical platform
3.1.15
OCF Resource
represents an artefact modelled and exposed by the OCF Framework
3.1.16
OCF Resource Property
significant aspect or notion including metadata that is exposed through the OCF Resource (3.1.15)
3.1.17
OCF Resource Type
OCF Resource Property (3.1.16) that represents the data type definition for the OCF Resource (3.1.15)
3.1.18
OCF Server
logical entity with the role of providing resource state information and allowing remote control of its
resources
3.1.19
Virtual Bridged Client
logical representation of an OCF Client (3.1.13), which an OCF Bridge Device (3.1.12) exposes to
Bridged Servers (3.1.10).
3.1.20
Virtual Bridged Server
logical representation of an OCF Server (3.1.18), which an OCF Bridge Device (3.1.12) exposes to
Bridged Clients (3.1.5).
3.1.21
Virtual OCF Client
logical representation of a Bridged Client (3.1.5), which an OCF Bridge Device (3.1.12) exposes to
OCF Servers (3.1.18)
3.1.22
Virtual OCF Device
Virtual OCF Client (3.1.21) or Virtual OCF Server (3.1.24).
3.1.23
Virtual OCF Resource
logical representation of a Bridged Resource (3.1.8), which an OCF Bridge Device (3.1.12) exposes to
OCF Clients (3.1.13)
3.1.24
Virtual OCF Server
logical representation of a Bridged Server (3.1.10), which an OCF Bridge Device (3.1.12) exposes to
OCF Clients (3.1.13).
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ISO/IEC 30118-3:2021(E)
3.2 Symbols and abbreviated terms
CRUDN Create, Read, Update, Delete, and Notify
4 Document conventions and organization
4.1 Conventions
In this document a number of terms, conditions, mechanisms, sequences, parameters, events, states,
or similar terms are printed with the first letter of each word in uppercase and the rest lowercase (e.g.,
Network Architecture). Any lowercase uses of these words have the normal technical English meaning.
In this document, to be consistent with the IETF usages for RESTful operations, the RESTful operation
words CRUDN, CREATE, RETRIVE, UPDATE, DELETE, and NOTIFY will have all letters capitalized.
Any lowercase uses of these words have the normal technical English meaning.
4.2 Notation
In this document, features are described as required, recommended, allowed or DEPRECATED as
follows:
Required (or shall or mandatory).
– These basic features shall be implemented to comply with this document. The phrases “shall not”,
and "PROHIBITED" indicate behaviour that is prohibited, i.e. that if performed means the
implementation is not in compliance.
Recommended (or should).
– These features add functionality supported by this document and should be implemented.
Recommended features take advantage of the capabilities of this document, usually without
imposing major increase of complexity. Notice that for compliance testing, if a recommended
feature is implemented, it shall meet the specified requirements to be in compliance with these
guidelines. Some recommended features could become requirements in the future. The phrase
"should not" indicates behaviour that is permitted but not recommended.
Allowed (or allowed).
– These features are neither required nor recommended by this document, but if the feature is
implemented, it shall meet the specified requirements to be in compliance with these guidelines.
– Conditionally allowed (CA)The definition or behaviour depends on a condition. If the specified
condition is met, then the definition or behaviour is allowed, otherwise it is not allowed.
Conditionally required (CR)
– The definition or behaviour depends on a condition. If the specified condition is met, then the
definition or behaviour is required. Otherwise the definition or behaviour is allowed as default
unless specifically defined as not allowed.
DEPRECATED
– Although these features are still described in this document, they should not be implemented except
for backward compatibility. The occurrence of a deprecated feature during operation of an
implementation compliant with the current document has no effect on the implementation’s
operation and does not produce any error conditions. Backward compatibility may require that a
feature is implemented and functions as specified but it shall never be used by implementations
compliant with this document.
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ISO/IEC 30118-3:2021(E)
Strings that are to be taken literally are enclosed in "double quotes".
Words that are emphasized are printed in italic.
5 Introduction
5.1 Translation between OCF and non-OCF ecosystem - primitive concept of
Bridging
The details of Bridging may be implemented in many ways, for example, by using a Bridge Platform
with an entity handler to interface directly to a Non-OCF device as shown in Figure 1.
OCF
Heart Rate
Non-OCF
Device
Bridge Platform Sensor
Protocol
(as Client)
Device
Non-OCF ecosystem
Figure 1 – Server bridging to Non- OCF device
On start-up the Bridge Platform runs the entity handlers which discover the non-OCF systems (e.g.,
Heart Rate Sensor Device) and create Resources for each Device or functionality discovered. The
entity handler creates a Resource for each discovered Device or functionality and binds itself to that
Resource. These Resources are made discoverable by the Bridge Platform.
Once the Resources are created and made discoverable, then the Client Device can discover these
Resources and operate on them using the mechanisms described in ISO/IEC 30118-1. The requests
to a Resource on the Bridge Platform are then interpreted by the entity handler and forwarded to the
non-OCF device using the protocol supported by the non-OCF device. The returned information from
the non-OCF device is then mapped to the appropriate response for that Resource.
Current OCF Bridging architecture implements the entity handler in the form of VOD.
5.2 Bridge platform
This clause describes the functionality of a Bridge Platform; such a device is illustrated in Figure 2.
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Bridging Function
ISO/IEC 30118-3:2021(E)
Bridge Platform
Bridge
Virtual Virtual
OCF Bridged
OCF Bridged
OCF Bridged
Protocol Protocol
Server Client
Client Server
Virtual Virtual
OCF Bridged
OCF Bridged
OCF Bridged
Protocol Protocol
Client Server
Server Client
Figure 2 – Bridge Platform components
A Bridge Platform enables the representation of one or more Bridged Devices as Virtual OCF Devices
(VODs) on the network and/or enables the representation of one or more OCF Devices as Virtual OCF
Devices using another protocol on the network. The Bridged Devices themselves are out of the scope
of this document. The only difference between a native OCF Device and a VOD from the perspective
of an OCF Client is the inclusion of "oic.d.virtual" in the "rt" of "/oic/d" of the VOD.
A Bridge Platform exposes a Bridge Device which is an OCF Device with a Device Type of
"oic.d.bridge". This provides to an OCF Client an explicit indication that the discovered Device is
performing a bridging function. This is useful for several reasons; 1) when establishing a home network,
the Client can determine that the bridge is reachable and functional when no bridged devices are
present, 2) allows for specific actions to be performed on the bridge considering the known functionality
a bridge supports, 3) allows for explicit discovery of all devices that are serving a bridging function
which benefits trouble shooting and maintenance actions on behalf of a user. When such a device is
discovered the exposed Resources on the OCF Bridge Device describe other devices. For example,
as shown in Figure 3.
OCF facing
Bridged Devices
Bridge Platform
Fan
Virtual OCF Server 1
(oic.d.fan)
Virtual OCF Server 2
Light 1
(oic.d.light)
Virtual OCF Server 3
(oic.d.light)
Light 2
Figure 3 – Schematic overview of a Bridge Platform bridging non-OCF devices
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Bridging Function
ISO/IEC 30118-3:2021(E)
It is expected that the Bridge Platform creates a set of devices during the start-up of the Bridge Platform,
these being the Bridge and any known VODs. The exposed set of VODs can change as Bridged
Devices are added or removed from the bridge. The adding and removing of Bridged Devices is
implementation dependent.
5.3 Symmetric vs. asymmetric bridging
There are two kinds of bridging: symmetric and asymmetric. In symmetric bridging, a bridge device
exposes OCF server(s) to another ecosystem and exposes other ecosystem’s server(s) to OCF. In
asymmetric bridging, a bridge device exposes OCF server(s) to another ecosystem or exposes another
ecosystem’s server(s) to OCF, but not both. The former case is called an Asymmetric Server Bridge
(see Figure 4), the latter case is called an Asymmetric Client Bridge (see Figure 5)
Bridge Platform
Bridged
Bridged
Server #1
OCF
OCF Virtual OCF
Protocol
Protocol Server #1
Client #1
Virtual
OCF
Bridged
Protocol
Client(s)
Virtual OCF
OCF
OCF
Bridged
Server #2
Protocol
Bridged
Protocol
Client #2
Server #2
Not in scope
of OCF Bridging spec
Figure 4 – Asymmetric server bridge
In Figure 4 each Bridged Server is exposed as a Virtual OCF Server to OCF side. These Virtual OCF
Servers are same as normal OCF Servers except that they have additional rt value ("oic.d.virtual") for
"/oic/d". The details of the Virtual Bridged Client are not in scope of this document.
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Bridging Function
ISO/IEC 30118-3:2021(E)
Bridge Platform
Bridged Client #1
(Read-Write Server #1)
Virtual OCF Client
OCF
(Aligned to:
Server #1
RW ACL on Server #1)
Virtual
Bridged Client #2
Bridged
(Read-Write Server #1)
Server(s)
Virtual OCF Client
(Aligned to:
OCF
RO ACL on Server #1,
Server #2
RW ACL on Server #2)
Bridged Client #3
(Read-Only Server #1)
Not in scope
of OCF Bridging spec
Figure 5 – Asymmetric client bridge
Figure 5 shows that each access to the OCF Server is modelled as a Virtual OCF Client. Those
accesses can be aggregated if their target OCF servers and access permissions are same, therefore
a Virtual OCF Client can tackle multiple Bridged Clients.
5.4 General requirements
5.4.1 Requirements common to all bridge platforms
A VOD shall have a Device Type that contains "oic.d.virtual". This allows Bridge Platforms to determine
if a device is already being translated when multiple Bridge Platforms are present or Clients to
determine if corresponding Server is a VOD or not.
Each Bridged Device shall be exposed as a separate Virtual OCF Server or Client, with its own OCF
Endpoint, and set of mandatory Resources (as defined in ISO/IEC 30118-1 and ISO/IEC 30118-2).
Discovery of a VOD is the same as for an ordinary OCF Device; that is the VOD shall respond to
multicast discovery requests. This allows platform-specific, device-specific, and resource-specific
fields to all be preserved across translation.
The Bridge Introspection Device Data (IDD) provides information for the Resources exposed by the
Bridge only. Each VOD shall expose an instance of "oic.wk.introspection" which provides a URL to an
IDD for the specific VOD.
5.4.2 Requirements specific to symmetric bridge platforms
In addition to the requirements mentioned in 5.4.1, Symmetric Bridging shall satisfy following
requirements.
The Bridge Platform shall check the protocol-independent UUID ("piid" in OCF) of each device and
shall not advertise back into a Bridged Protocol a device originally seen via that Bridged Protocol. The
Bridge Platform shall stop translating any Bridged Protocol device exposed in OCF via another Bridge
Platform if the Bridge Platform sees the device via the Bridged Protocol. Similarly, the Bridge Platform
shall not advertise an OCF Device back into OCF, and the Bridge Platform shall stop translating any
OCF device exposed in the Bridged Protocol via another Bridge Platform if the Bridge Platform sees
the device via OCF. These require that the Bridge Platform can determine when a device is already
being translated. A VOD shall be indicated on the OCF Security Domain with a Device Type of
"oic.d.virtual".
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ISO/IEC 30118-3:2021(E)
The Bridge Platform shall detect duplicate VODs (with the same protocol-independent UUID) present
in a network and shall not create more than one corresponding virtual device as it translates those
duplicate devices into another network.
5.5 VOD list
For maintenance purposes, the Bridge maintains a list of VODs. This list includes Virtual OCF Servers
and Virtual OCF Clients created by the Bridge Platform and subsequently on-boarded, as specified in
ISO/IEC 30118-2. A single instance of the Resource Type that defines the VOD list (see clause 7.2)
shall be exposed by the Bridge. Please refer to ISO/IEC 30118-2 for detailed operational requirements
for the VOD list.
5.6 Resource discovery
A Bridge Platform shall detect devices that arrive and leave the Bridged network or the OCF Security
Domain. Where there is no pre-existing mechanism to reliably detect the arrival and departure of
devices on a network, a Bridge Platform shall periodically poll the network to detect the arrival and
departure of devices, for example using COAP multicast discovery (a multicast RETRIEVE of "/oic/res")
in the case of the OCF Security Domain. Bridge Platform implementations are encouraged to use a
poll interval of 30 seconds plus or minus a random delay of a few seconds.
A Bridge Platform and any exposed VODs shall each respond to network discovery commands. The
response to a RETRIEVE on "/oic/res" shall only include the devices that match the RETRIEVE request.
For example, if a Bridge exposes VODs for the fan and lights shown in Figure 3, and an OCF Client
performs a discovery request with a content format of "application/vnd.ocf+cbor", there will be four
discrete responses, one for the Bridge, one for the virtual fan Device, and two for the virtual light
Devices. Note that
...

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