Internet Inter-ORB Protocol

What Does Internet Inter-ORB Protocol Mean?

Internet Inter-ORB Protocol (IIOP) is an object-oriented protocol used to facilitate network interaction between distributed programs written in different programming languages. IIOP is used to enhance Internet and intranet communication for applications and services.


IIOP is an integral component of the Common Object Request Broker Architecture (CORBA), which is a well-known IT industry standard. IIOP is an implementation of General Inter-ORB Protocol (GIOP), which is an abstract interation protocol used by object request brokers (ORB).

IIOP is similar to Microsoft’s Distributed Component Object Model (DCOM), which is a primary CORBA/IIOP competitor.

Techopedia Explains Internet Inter-ORB Protocol

Like CORBA, IIOP follows a client-server architecture for communication, where a message request is always transmitted from a client to a server.

Object Management Group (OMG) specifications for IIOP are as follows:

  • Common Data Representation (CDR): Provides a standard data encoding/decoding method
  • Interoperable Object Reference (IOR): The client must have a program address, known as an IOR, prior to sending a server request. The IOR is based on the IP address and port numbers of the server and is usually mapped to a value table created by the client’s computer.
  • Message formats defined to support CORBA’s ORB specifications

IIOP advantages include:

  • Better architecture neutrality
  • Communication transparency
  • Scalability
  • Code reusability

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Margaret Rouse
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Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.