and the proliferation of different organizations working on 5G requirements, use cases, best practices, and standards. While some of them are undoubtedly important, such as 3GPP, IEEE, BBF, O-RAN, and IETF, the role of the others is hard to predict at the moment. The end result of this situation is that, on one hand, there is likely to be only one major 5G standard to implement (based on 3GPP specifications), however that standard will have many more options compared with similar standards in the past. 5G standard has effec- tively become a "toolbox" rather than a single standard, out of which different vendors and different operators will select features that they find useful to implement. How the market will deal with that situation remains to be seen. 2.10 Role of Open Source While standards remain undoubtedly important and arguably irreplaceable, at least on the air interface, an alternative to standards is starting to emerge in the form of open source. Ultimately, standards help to ensure multi-vendor interoperability, especially when there is a conformance certification process, which is often developed to accompany a standard. The same result can be achieved through open source. With the open source paradigm, companies that would otherwise contribute to the development of a specification (to be used for development of interoperable products), contribute to an open source project that everybody can use - thus achieving interoperability by the virtue of the fact that all ven- dors would presumably have the same baseline implementation. This of course does not necessarily mean that open source makes all products identical, just as conformance to a common standard does not necessarily mean that all conforming products are the same. Just as a good standard leaves room for differentiation by specifying only what needs to be specified, an open source implementation may still allow extensions and enhancements (depending on the open source license used, as explained below). Open source initiatives have been extreme