The present document provides architecture and functional requirements for business trunking for the Next Generation Network.

The present document also specifies the protocol requirements for the NGCN to attach to the NGN (in particular the IM CN subsystem) and also any protocol requirements relation to application servers provided in support of business trunking.

Business trunking is a set of NGN capabilities that may be applied to communications between Next Generation Corporate Networks (NGCN) using the NGN as a transit.

The structure of the present document reflects the historical structure of previous versions of it. All references to ETSI TS 124 525 [30] are intended to be to the entire contents of the referenced document, which now forms the contents of the present document, and not to any part which might be implied by any headings within the present document.