For disciplinary and domain applications, systems interoperability largely deals with the adoption of agreed technologies, standards, specifications and interfaces with a disciplinary/domain service bus or means of information exchange, if available. However, multi-disciplinary efforts make more complex demands on the type of systems and arrangements needed to support cross-domain activities. Thus, interoperability among diverse disciplinary and domain systems must be pursued adopting more flexible and sustainable approaches. This paper discusses the challenges for multi-disciplinary interoperability. The recent Brokering approach is introduced; this solution aims at interconnecting the heterogeneous disciplinary and domain service buses, avoiding the imposition of any federated or common specification. It can deliver a range of services such as discovery and access through a Broker Framework. The Brokering approach has been successfully introduced by the EuroGEOSS research project and recently adopted by the GEOSS Common Infrastructure (GCI). US NSF EarthCube initiative also has recognized the importance of brokering for its reference architecture. The GI-* technology, empowering the EuroGEOSS and the GCI brokering frameworks, is presented and discussed.