Interconnecting in a multi-vendor, multi-network, multi-service environment

The Centre of Excellence for interoperability in a multi-polar interconnected world

Interoperability is driven by market demand. It gives users much greater choice of products, and allows manufacturers to benefit from the economies of scale of a wider market. In order to achieve interoperable products and services, clean unambiguous standards need to be developed and followed.

A unique approach to interoperability

Our Centre for Testing and Interoperability (CTI) provides hands-on expertise in standards validation to support our standardization activities through:

  • the organization of our highly regarded Plugtests™ interoperability events
  • the development of test specifications
  • the application of protocol specification techniques
  • the use of ‘best practice’ methodologies.

Our CTI works closely with our Technical Committee for Methods for Testing and Specification (TC MTS). TC MTS creates standards related to testing and specification languages and provides frameworks, guidelines and methodologies for other ETSI committees to achieve this goal. Much of the work done by TC MTS has also been adapted and used globally by other organizations, fora and industry bodies.

ETSI is unique among Standards Development Organizations in having pioneered the combined use of these practices. As a result we deliver interoperable standards of consistently high quality.

ETSI test specifications

For over 20 years ETSI has been a pioneer among standardization bodies in recognizing the importance of achieving interoperability through testing. Many key ETSI technologies have an accompanying set of standardized test specifications that may be used by ETSI Members and others for in-house product development or industrial certification schemes.

ETSI test specifications are written using Testing and Test Control Notation Version 3 (TTCN-3). TTCN-3 is a standardized test specification language developed and maintained by ETSI’s TC MTS and specifically designed for testing and certification. TTCN-3 is used in a variety of application domains and types of testing in industry, research, international projects and academia. The ETSI TTCN-3 standards have also been adopted by the ITU-T in the Z.160 series.

Validation through ETSI interoperability events

ETSI organizes interoperability events, or Plugtests™. These are a well-proven and cost-effective approach to validate standards for interoperability, through validating the interoperability of equipment based on the standards.

These events bring together engineers and equipment in a neutral environment where they can execute a large variety of real-life scenarios in various combinations.

Interoperability events provide an open forum for resolving issues of non-interoperability and other technical aspects related to standards development and validation. It is a place for engineers to meet in a very practical environment and to provide feedback to the standardization groups.

ETSI has organized almost 200 Plugtests worldwide, covering well over 50 technologies. For more information please visit logo plugtests


Over the years, interoperability activities have been a feature of most ETSI committees:

  • 3GPP - Continued development of user equipment test specifications for use by GCF (Global Certification Forum), PTCRB (North America) and TDIA (China), and organization of a series of small cell interoperability events with the Small Cell Forum
  • AERO - A series of Plugtests with EUROCAE on VoIP for ATM (Air Traffic Management) to improve the robustness between Voice Communication Systems (VCS) as well as the interworking between VCS and Ground Radio Stations (GRS)
  • ATTM - A series of Plugtests with the Fixed Services and Networks Alliance on Gigabit Passive Optical Networks (GPON)
  • BRAN - Development of conformance test specifications, interoperability test specifications and the organization of interoperability events with the WiMAX Forum
  • CABLE – development of test specifications and interoperability events for IPv6 Transitioning
  • CLOUD - Organization of GRID interoperability events and demonstrations with the Open Grid Forum (closed now)
  • DECT - Development of conformance test specifications for the DECT standards and more recently working with the DECT Forum on the organization of interoperability events for Cordless Advanced Technology- Internet and Quality interoperability events (CAT-iq)
  • eHealth - Participation in IHE (Integrating the Healthcare Enterprise) CONNECTATHON events with the provision of state-of-the-art TTCN-3 test tools for HN7 profiles
  • ERM - Development of test specifications for PMR (Public Mobile Radio), DMR (Digital Mobile Radio) and the organization of several RFID Plugtests.
  • ESI - Development of an interoperability portal to facilitate remote interoperability events for standards XAdES, CAdES, PAdES (Advanced Electronic Signature) and ASiC
  • HF - Plugtests events for handsets from a user perspective
  • INT - Development of test specifications and organization of Plugtests for IMS (Internet Multi-media Subsystem) and RCS (Rich Communication Suite)
  • ITS - Development of test specifications and test frameworks, as well as interoperability events on Cooperative Mobile Systems and Road Toll Systems/DSRC co-existence
  • LI - Organization of interoperability events for Lawful Interception
  • M2M and IoT (related) – M2M interoperability demonstrations and CoAP and 6LowPAN interoperability events
  • MSG – eCall interoperability events in partnership with ERTICO
  • MTS - Development of specification techniques including TTCN-3 and testing methodologies such as Automated Interoperability TestingNTECH - Development of test specifications for NGN
  • oneM2M – Interoperability demonstrations
  • PLT - Organization of co-existence testing events between PLT and ADSL
  • SCP - Prototype testing tools and methodology for ePassport readers (jointly with MTS)
  • SmartM2M – Interoperability demonstrations
  • STQ - Organization of speech quality test events
  • TETRA - Development of test specifications (now TCCE - TETRA and Critical Communications Evolution)


Test specifications

Our Core Network and Interoperability Testing committee (TC INT) assists the industry with the deployment of the Internet Protocol (IP) Multimedia Subsystem (IMS) by producing high quality test specifications.

We are developing conformance test specifications for the Diameter protocol, for use in roaming. We will continue to develop LTE test specifications for terminal certification and conformance test specifications for LTE.

Conformance testing during the development phase of Evolved Packet Core (EPC) and IMS products will significantly reduce the time-to-market of the LTE architecture, as protocol conformant products will be less likely to cause interoperability problems with the products of other vendors.

We are also consolidating the Intelligent Transport Systems (ITS) conformance and interoperability validation platform and developing conformance test specifications for Digital Enhanced Cordless Telecommunications (DECT™).

Methods for testing and specification

Our Methods for Testing and Specification committee (TC MTS) plays a significant role in the market success of numerous technologies. The main focus is the Test Description Language (TDL), a new language for the specification of test descriptions and the presentation of test execution results, primarily for functional testing, but also potentially for other types of testing.

TDL will fill the gap between the simple expression of what needs to be tested (the test purposes described in prose or Test Purpose Language) and the complex coding of the executable tests in Testing and Test Control Notation version 3 (TTCN-3). TDL exploits the benefits of model-based software engineering, accelerating test development without sacrificing quality. In effect, TDL represents the next generation of testing languages.

We also plan to produce a standardized concrete graphical syntax for end-users and a TDL exchange format to foster tool interoperability.

At the same time, we will continue to maintain TTCN-3, and to upgrade the conformance test suite for the TTCN-3 core language, to take account of the latest evolution of the language and to extend the coverage of the suite.

In the security area, we are drafting a Technical Specification (TS) on security testing terminology and an ETSI Guide (EG) on the security assurance lifecycle.

Plugtests events

Plugtests are organized on a variety of subjects, depending on demand. Current activities are dominated by technologies related to Machine-to-Machine (M2M) communications and the Internet of Things (IoT), including Constrained Application Protocol and IPv6 over low power Wireless Personal Area Networks, Small Cell technologies, the ETSI M2M architecture, semantic interoperability, home appliances and Vehicle2Grid.

Other subjects of importance are Network Functions Virtualization and eCall, the European in-vehicle emergency call service.

Following the success of our testing of Electronic Signatures in support of European Commission (EC) Mandate 460, we have been awarded an EC grant to carry out eight more remote Electronic Signatures and Infrastructures events over the next two years.