EI-Agent Handshake Protocol

Message Topics

• MQTT Topic Define
  • From Server to Agent:
    /wisepaas/<tenantId>/<product>/<agentId>/<function>ack
  • From Agent to Server:
    /wisepaas/<tenantId>/<product>/<agentId>/<function>req

• Preserved Topic for Common use, the product name "device" is preserved for common use.
  • Agent Registration Topic:  /wisepaas/<tenantId>/device/<agentId>/agentinfoack
  • Will Message Topic:  /wisepaas/<tenantId>/device/<agentId>/willmessage Or /wisepaas/<tenantId>/device/<serverId>/willmessage
  • Command Topic:  /wisepaas/<tenantId>/device/<agentId>/agentactionreq
  • Response Topic:  /wisepaas/<tenantId>/device/<agentId>/agentactionack
  • Report Data Topic:  /wisepaas/<tenantId>/device/<agentId>/devinfoack
• Custom Topic Sample
  • ​For example, the product name is "custom" and function name is "powerctrl", the topic for Power ON/OFF control will be:
    • Server send command with topic: /wisepaas/<tenantId>/custom/<agentId>/powerctrlreq
    • Agent send response with topic: /wisepaas/<tenantId>/custom/<agentId>/powerctrlack

Handshake Sequence

Normal sign in and sign out sequence:

Agent lost connection with will message sequence:

Server lost connection with will message sequence:

Data Format

Agent ID Format

• Format define

Agent ID Format is based on UUID format, which is represented as 32 characters, displayed in six groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters. In this format the UUID could map to Agent ID directly.

For example:

The UUID is: 

 123e4567-e89b-12d3-a456-426655440000

Mapping to the Agent ID is:

 123e4567-e89b-12d3-a456-426655440000

• Generate Agent ID

If the target device has it own unique ID, but less the 32 characters, then we could follow the steps to generate the Unique Agent ID:

1. Retrieve Unique ID as key, for example: MAC address or IMEI.
2. The first 8 digits is predefined to identify the Unique ID source.
   • 00000001: MAC
   • 00000002: IMEU
   • 00000004: Hardware System config, ex: "/sys/fsl_otp/HW_OCOTP_CFG0"
   • 00000005: Custom generates serial number. The serial number may not be unique, so we add the product or brand name before the serial number to make sure the ID is unique. 
3.  Add 'Zero'(0) to extended to 24 lowercase hexadecimal digits as UUID format.

For example:

Unique ID with MAC address:

MAC:

 000babbb7ef3 

Agent ID:

00000001-0000-0000-0000-000babbb7ef3

Custom Serial number:

Serial number for Advantech ARK 1120 :

 KSA0451097

Agent ID:

00000005-0000-0000-000a-rkksa0451097

Basic JSON Format

• JSON (JavaScript Object Notation) is a lightweight data-interchange format.
• JSON is built on two structures:
  • A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
  • An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.
• JSON Forms:

Object: { string : value} Array: [ value ] Value: string       number       object       array        true        false        null

• WISE-PaaS predefined string:
  • agentID: target device ID, value type is string.
  • handlerName: target device supported function block (Plugin or Handler) name, value type is string.
  • commCmd: the sub command ID in function block (Plugin or Handler), value type is unsigned integer.
  • content: the contain data.
  • opTS: message generated time stamp (optional), the unit is millisecond.
    • format: "opTS":{"$date":1494308768000}
• Device Registration Format:

{   "agentID":"00000001-0000-0000-0000-000babbb7ef3",   "handlerName":"general",         //defined for device registration   "commCmd":1,                          //defined for device registration   "content": {      "parentID":"",                                //the parent device ID if the target device has parent device.     "hostname":"PC001104",            //target device name     "sn":"14DAE996BE04",                //target device serial number     "mac":"14DAE996BE04",            //target device mac address     "version":"1.0.0.0",                     //client application version     "type":"IPC",                                  //target device type     "tag":"RMM,Custom",               //target device  tag for supported software product name.     "product":"",                                   //target device hardware product name     "manufacture":"",                         //target device hardware manufacture     "account":"anonymous",            //bind target device to a specific account     "password":"",                               //encrypt with DES and Base64     "status":1                                         //1: registration, 0: un-registration   } }

 

• Report Data Format:

{   "agentID":"00000001-0000-0000-0000-000babbb7ef3",   "handlerName":"general",   "commCmd":2055,   "content":{     "opTS":{"$date":1494308768000},     "custom_object":{                      //User defined report data object.       "custom_data1":"string_value",       "custom_data2":123,       "custom_data3":false     }   } }

IPSO Format (Application Framework)

The IPSO Application Framework makes use of IETF standards as building blocks for a simple and efficient RESTful design model for IP smart objects. The framework may be used over either HTTP or CoAP web transfer protocols. HTTP, REST, XML, JSON, COAP and other key components of web technology are powerful mechanisms in an Internet of Things application.

Note: The objective of the Alliance is not to define technologies, but to document the use of IP-based technologies defined at the standard organizations such as IETF with focus on support by the Alliance of various use cases.   Function Sets: The framework is organized into groups of resource types called Function Sets.  A Function Set has a recommended root path, under which its sub-resources are organized.  Each Function Set is assigned a Resource Type parameter, therefore making it possible to discover it.  

Function Set	Root Path	Resource Type
General Purpose IO	/gpio	gpio
Power	/pwr	pwr
Load Control	/load	load
Sensors	/sen	sen
Light Control	/lt	lt
Message	/msg	msg
Location	/loc	loc
Configuration	/cfg	cfg

 

• IPSO Smart Object

IPSO Smart Object [2] Guidelines provide a common design pattern, an object model, which can effectively use the IETF CoAP protocol to provide high level interoperability between Smart Object devices and connected software applications on other devices and services

The common object model is based on the Lightweight M2M (LWM2M 1.0) specification from the Open Mobile Alliance. OMA LWM2M is a device management and service architecture specification based on IETF CoAP, and provides a simple and flexible object template (object model) for constrained device management.

The object model from OMA LWM2M is reused to define application level IPSO Smart Objects. This enables the OMA Name Authority (OMNA) to be used to register new objects, and enables existing LWM2M compliant device libraries and server software to be used as an infrastructure for IPSO Smart Objects

 

• Media Types for Sensor Markup Language (SENML)
  • Semantics

SenML	JSON	Type	Description
Base Name	bn	String	This is a string that is prepended to the names found in the entries
Base Time	bt	Integer	A base time that is added to the time found in an entry
Base Units	bu	String	A base unit that is assumed for all entries, unless otherwise indicated
Version	ver	Number	Version number of media type format
Measurement or Parameters	e	Array	Array of values for sensor measurements or other generic parameters
Name	n	String	Name of the sensor or parameter
Units	u	String	Units for a measurement value
Value	v	Float	Value of the entry
String Value	sv	String
Boolean Value	bv	Boolean
Value Sum	s	Float	Integrated sum of the values over time
Time	t	Integer	Time when value was recorded
Update Time	ut	Integer	Update time. A time in seconds that represents the maximum time before this sensor will provide an updated reading for a measurement.

 

• The Data Type of Sensor Data Type

Data Type (type)	SenML Field
b (boolean)	bv
s (string)	s
e (enum)	e
i (integer)	v
d (decimal)	v
h(hexadecimal)	s
o(octet-stream)	s

 

• Advantech Sensor Semantics

SenML	JSON	Type	Description
Min Range Value	min	Float	The minimum value that can be measured by the sensor
Max Range Value	max	Float	The maximum value that can be measured by the sensor
Access Mode	asm	String	The access mode of the resource. Ex: read (r), write (w), read/write (rw)
Standard Format	st	String	The sensor format is which standard format
Health Status	Health	Integer	The health status of network or device. Range: -1 ~ 100 Good: > 80, Average: 60 ~ 80, Below Average: 40~60, Bad:0~40, -1: Off line or Fault

 

• IPSO Report Data Format:

{   "agentID":"00000001-0000-0000-0000-000babbb7ef3",   "handlerName":"general",   "commCmd":2055,   "content":{     "opTS":{"$date":1494308768000},     "custom_object":{                      //User defined report data object in IPSO format.       "bn":"custom_object",       "e":[         {"n":"custom_data1","sv":"string_value"},         {"n":"custom_data2","v":123},         {"n":"custom_data3","bv":false}       ]     }   } }