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

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 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/