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O-MI vs O-DF: Understanding the Differences in IoT

iot data format open messaging interface data communication interoperability

This article compares O-MI and O-DF, two important formats used in the Internet of Things (IoT) for interoperability. It outlines the key differences between their functions and formats.

O-MI stands for Open Messaging Interface, while O-DF stands for Open Data Format.

Here are the key features of both O-MI and O-DF:

  • These formats are published by the Open Group.
  • O-MI and O-DF have a similar relationship to HTTP and HTML used on the web, respectively.
  • They can be used independently of each other.
  • O-MI, as the name suggests, is used for communication between IoT devices.
  • O-DF, also as the name implies, is used as the data or payload format for communication between IoT devices.
  • Both are specified using XML schema.
  • They can be transported by any underlying protocol, such as HTTP, HTTPS, FTP, SMTP, XMPP, etc.
  • They facilitate publishing and discovering available information and services.
  • Read and Write operations for immediate information, historical information, alerts, and events can be performed using these formats.
  • It is possible to subscribe to information using the Observer Design Pattern.

O-MI: Open Messaging Interface

O-MI Open Messaging Interface

O-MI supports operations like read, write, subscribe, and cancel, as described below:

  • Read: Retrieves current and historical information, events, alerts, etc.
  • Write: Sends information such as sensor values, alerts, events, set points, etc.
  • Subscribe: Allows you to subscribe to information with various options, including:
    • Ad-hoc subscriptions
    • Time-limited subscriptions (event-based vs. regular interval)
    • Piggybacking
    • With or without callback
  • Cancel: Cancels subscriptions before their expiration.

O-DF: Open Data Format

  • O-DF is a generic format that represents “anything” within the IoT domain.
  • The same structure is used to publish, discover, query, and retrieve information.
  • It can be extended, similar to the class inheritance concept in Object-Oriented Programming (OOP).
  • Taxonomy may be provided by open group standards such as UDEF.

Reference

www.opengroup.org/