In a nutshell, the SDB is to European air transport what the contracts with a Telco Provider and an Internet Service Provider are for a household. The household purchases the “ICT Services” offered by the providers, and monitors that the services are provided as agreed. It does not get involved in the inner workings of how the providers go about producing these services.
The main difference is that air transport requires a multitude of interdependent contracts because the business is so complex. For example, different technologies are required for ground-ground and air-ground information exchanges so there need to be different contracts. But since the information needs to flow between all actors involved in the air transport value chain (e.g.pilots, dispatchers, controllers, ground handlers…), these contracts are interrelated.