Multi-Link DevicesGroup Name: WG1Source: Kaonmedia, KETIContact: Hwang Kwang Tae (kthwang@kaonmedia.com) , Yong-Suk Park (yspark@keti.re.kr) Meeting Date: 2014-10-31Agenda Item: Discussion

REQ-2014-0485R01-Usecase_for_multi-link_device

Motivation and Background

• One of the most widely used IoT/M2M applications is measuring energy consumption of a device (such as TV, fan, refrigerator, etc.)

• Because most of these devices do not have the capability to measure their own energy usage, a separate device is used to measure the energy usage

• Also, there are some devices that contain multiple small devices (sub-devices), but they register as a single device to the server (e.g. smart multi-tab serving multiple electric devices and measuring energy usage)

• Since a smart multi-tab is a single device and has a network connection to the server, the smart multi-tab can be registered as a node to the server. However, since the smart multi-tab sends packets containing energy usages of its connected devices, the measured values should be assigned to appropriate applications

• However, the current oneM2M architecture does not provide this kind of device and message handling

• The oneM2M specification standardizes a link between resources, but the link in the specification is only for simple child and parent relationship

IoT/M2M systemIoT/M2M systemCSE-Base

CSEs

CSE.1

applications

GA.1

attributes

applications

GA.1

attributes

applications

GA.1

attributes

applications

GA.1

attributes

for fan

for toaster

for refrigerator

for smart multi-plug

All measured data are stored under smart multi-plug resource although the values are for other devices

Background and Motivation

Delivery of measured data• If a smart multi-plug sends a packet, the packet contains measured data of the devices

plugged-in

• There should be a mechanism to deliver measured values to the corresponding connected device

• For example, let’s assume that there are three devices (A: refrigerator, B: toaster and C: fan) plugged in sockets 1, 2 and 3 of a smart multi-plug, respectively, and that the smart multi-plug can send measured data regularly to the server

• The packet created by the smart multi-plug has to contain – all measured values from connected devices– an indication that this packet is coming from a device serving multiple devices– pair of values distinguishing devices and their measured values, for example, A:30.B:20.C:40 or

A.B.C=30.20.40. This indicates that devices A, B and C consume 30, 20 and 40 watts, respectively• If there is no indication in the packet, the server has to know about the type of devices when the device

is registered. Therefore, if the value is delivered to the resource of such muti-homed devices, the server has to perform some actions, such as parsing and distributing values to the proper corresponding resources

Delivery of measured data• For this purpose, CMDH (Communication Management and Delivery Handling)

requires to perform additional functions as follows: – Option 1:

• Detect a message from MLD (Multi-Linked Device)• If the message is coming from MLD, perform parsing based on the packet rules (such as msg

type + device id + value + device id + value, etc.)• After the parsing, CMDH stores the values to the appropriate resources

– Option 2: • Store the given value from a message from MLD to MLD’s resource• In this case, we require an additional resource type called MLD resource • Once a value is stored into the MLD resource, the IN-CSE parses the stored value and

distributes the parsed values into the proper resources.

The issue here is whether to perform parsing and distributing the values based on message type or resource type

The issue here is whether to perform parsing and distributing the values based on message type or resource type

Delivery of measured data

- an indication that this packet is coming from a device serving multiple devices- pair of values to distinguish devices

1 . A . 30 .

indication

delimiter

Device id

delimiter

value

IN-CSE

CMDH

- Parsing- Distributing