# [Intern] 25/07/2022 Conformance and Interoperability Testing
###### tags: `BMW-Lab`, `Intern`

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**Goal:** To understand the conformance and interoperability testing.
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**References**
- [Conformance and Interoperability Testing](https://www.5gtechnologyworld.com/why-5g-o-rans-need-compliance-and-interoperability-testing/)
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## Conformance and Interoperability Testing

Making the new open RAN work demands stringent test requirements. In the past, testing the eNB as a complete entity according to 3GPP requirements was enough. The required test points focused on the UE and backhaul interface. With the introduction of
the open RAN and a distributed RAN, it is now necessary to test each component in isolation for conformance to the standards. It is also important to test the components in combinations for interoperability. Conformance and interoperability testing are both necessary to correct any performance issues. Usually, completion of conformance testing happens first to ensure all elements
meet the required interface specifications. Interoperability testing occurs next to ensure all elements work together. Bypassing conformance testing and only relying on interoperability testing is equivalent to a car manufacturer assembling a car from
untested parts and only testing whether the car starts and runs. Conformance testing focuses on each component in isolation. Testing in isolation requires test equipment to emulate the surrounding network element to check all capabilities in the protocol. There are benefits to this approach not attainable with interoperability testing alone. These tests reduce the risk associated with deploying in an open RAN.

## Benefits of conformance test

• Stresses the device under test (DUT) to the limits of its stated capabilities.
• Exercises protocol features to test that interfaces and functions are working
as expected.
• Ensures your application is functioning properly by performing negative testing,
which is not possible in interoperability testing.

## Fronthaul conformance testing

Interoperability testing methodology changed minimally from 4G to 5G O-RAN. In interoperability testing, you simply test a combination of equipment as a gNB, similar to testing an eNB in 4G. Conformance testing is different for O-RAN conformance tests.

## Conformance test for the O-DU

The master node for the O-RAN fronthaul protocol is the O-DU. In the O-DU southbound interface, the control and user plane protocol messages come from the O-DU to the O-RU, except license assisted access (LAA) and uplink user plane data. The O-RU does
not acknowledge these messages; it merely carries them out in the best feasible way. The F1 northbound interface is a stream of data sent through the radio to one or more UEs. The F1 interface does not have a mechanism to direct the O-DU to format data,
which protocol elements to use, or how to send the data in time. That type of control is necessary to test the O-DU for O-RAN compliance but is only available through a dedicated port. For example, if you need to test non-contiguous resource block
allocations (section extension six) because a vendor’s radio supports it, it is not possible to force the O-DU to include that section extension in its C-plane messages. For this reason, the O-RAN conformance test specification chose to defer testing the O-DU until a later date.