Page 532 - 5G Basics - Core Network Aspects

1 Core network aspects

with one-to-multiple devices, multiple devices-to-one and multiple devices-to-multiple devices, several
capabilities in both the service stratum and the transport stratum would be required to extend (and/or to
define new capabilities) as illustrated in Figure 7-1.

7.1 Transport stratum

7.1.1 Transport functions
The transport functions provide the connectivity for all components and physically separated functions
within the NGN. These functions provide support for the transfer of media information as well as control
information. These functions also perform the delivery of services to user and cooperate with the mobility
management control function (MMCF) for maintaining service continuity during the device switchover. It also
can support fast switchover to cater to seamless non real-time and real-time service's requirements.

Figure 7-1 – High level architecture for application with multiple devices
based on [b-ITU-T Y.2012]
7.1.2 Transport control functions

The transport stratum provides connectivity to NGN users under the control of transport control functions
including network attachment control function (NACF), resource admission and control function (RACF) and
MMCF. More detailed information on NACF and RACF in NGN can be founded in [b-ITU-T Y.2014], [b-ITU-T
Y.2111] respectively.
According to [b-ITU-T Y.2012], NGN transport control functions are able to support different types of NGN
services in a common way. Application with multiple devices is expected to be supported by those functions
as well.
7.1.2.1 Network attachment control function (NACF)

The NACF provides the registration function to allow registration of NGN users at the access level and
provides the initialization of end-user functions so that the users can access NGN services including

522