Page 127 - 5G Basics - Core Network Aspects

Core network aspects 1

A resource is either a physical or a virtual component of a virtual network that executes specific functionality
and is represented with specific attributes. Three types of resources are introduced in the functional
architectures: physical resource, virtual resource, and LINP. All the three types of resources are managed
with corresponding management functions, which are usually implemented in management systems.

NOTE 1 – In Figure 1, end-user data transmission is represented with the blue lines and management and control with
the orange lines, as shown in the legend of symbols. Note that the blue lines are applied only to physical resources and
functions that manage them. This way of representation makes it clear for which purpose each reference point is
specified. For example, the user-to-network interface (UNI) reference point is specified for end-user data transmission,
whereas the virtual resource management interface (VMI) is specified for management and control. The same
representation is applied throughout this document. See clause 18 for more information about the reference points.
User roles are classified into one of the following four types: end-user, network operator, LINP operator, and
service developer. When LINP federation is performed, another type of role, LINP exchanger, may be
involved. These user roles are distinguished logically. Different types of user roles could be played by the
same party.
Each user role executes certain functions for the purpose of fulfilling its own responsibilities. When functions
of one user role need to access those of another, the accesses are done via reference points.
NOTE 2 – [b-ITU-T Y.3502] describes the reference architecture of cloud computing using two different views, i.e. the
user view and the functional view. In [b-ITU-T Y.3502], parties and roles appear in the user view and functions in the
functional view. The functional architecture presented in the present Recommendation can be understood as a
combination of the two views in the context of [b-ITU-T Y.3502]. As such, party as used in the present Recommendation
is similar to party as used in [b-ITU-T Y.3502] and user roles in the present Recommendation can be regarded as a
shortcut to roles in the user view in the context of [b-ITU-T Y.3502].

NOTE 3 – In this Recommendation, LINP operators are treated independently from network operators, while
[ITU-T Y.3012] describes LINP operators as being network operators. This approach allows for describing individual
functions in reference to user roles. In line with [ITU-T Y.3012], the party acting as a network operator can also act as
an LINP operator and as a service developer.

6.1 User roles

6.1.1 Network operator
Network operators are responsible for managing physical resources and their abstracted sets, or virtual
resources. For this purpose, they implement physical resource management functions and virtual resource
management functions, respectively, in their individual administrative domains.
A LINP is built from virtual resources in an administrative domain of a network operator. Accordingly,
implementing LINP management functions in an administrative domain is a responsibility of the
corresponding network operator. LINP management functions use virtual resource management functions
of the same administrative domain to allocate appropriate virtual resources to a specific LINP. Likewise,
virtual resource management functions use physical resource management functions of the same
administrative domain to allocate appropriate physical resources to a specific virtual resource.

Gateway functions are also implemented by network operators. Gateway functions are used to control
accesses from end-users to specific LINPs.

6.1.2 LINP operator

LINP operators activate or deactivate services on LINPs provided by network operators. ALINP operator can
also have access to LINP management services provided by a network operator. For this purpose, the LINP
operator interacts with virtual resource management functions and LINP management functions of the
administrative domain through the virtual resource management interface (VMI) and the LINP management
interface (LMI), respectively.

When LINP federation is required, LINP operator functions may use two or more virtual resource
management functions, each of which resides in different administrative domains. Examples are presented
in Figure 2 and Figure 3.

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