scope:

The present document defines the IP based signaling and media interfaces between any two GSM-R Core networks of a set of GSM-R Core networks that share a GIRA and that agree to interconnect via IP based technology.

Furthermore it defines the IP based signaling and media interface between any GSM-R Core network that wants to interconnect with other GSM-R Core networks via IP based technology - and a centralized hub during a distinct phase of migration.

The present document defines the IP Interconnect between 2 GSM-R Core networks - together with the interworking with BICC/ISUP at the edges of the networks - and the IP Interconnection between a GSM-R Core network and the current TDM hub - together with the interworking with ISUP at the current TDM hub and the interworking with BICC/ISUP at the edge of the GSM-R network.

Only the network layer (e.g. IP) and layers that build on the network layer are considered. The lower layers are denoted as L2 and L1 and are out of scope in the present document.

The present document will address all services (bearer services, tele services, supplementary services and railway services) that are defined by relevant EIRENE SRS [1].

The present document could address all domains of the GSM-R networks (e.g. CS domain, PS domain, IMS domain, etc.), however in a first step only the CS domain and the PS domain are covered.

The present document does not address any specific 3GPP Release or Architecture.