Page 258 - 5G Basics - Core Network Aspects

1 Core network aspects

Figure 6-2 assumes, as an example, that the MUE has two concurrent ongoing sessions:

– The first session is a SIP based communication. In this instance, the SIP based application is enhanced
for multi-connection since the service flow is decomposed between UMTS and Wi-Fi. In particular,
the flow related to SIP signalling is carried over UMTS while the user plane is transported over Wi-
Fi using UDP/RTP.

– The second session is a FTP session over Wi-Fi. In this case, the FTP application is not enhanced for
multi-connection.

The functional entities shown in yellow, support multi-connection, both in the UE and network nodes.
Clause 6.2 provides a description of the functional groups shown in Figure 6-1 while clause 6.3 describes the
functional entities used of the multi-connection architecture.

6.2 High level function descriptions

6.2.1 Transport function (TF)
The transport function provides the connectivity for all components and independent functions within NGN.
The function provides support for unicast and/or multicast transfer of media, as well as the transfer of control
and management signalling.
6.2.2 Multi-connection media function (MMF)

The multi-connection media function is responsible for enforcing multiple access policies including load
assignment and/or QoS to meet the requirement of multi-connection service experience.

The MMF performs the following functions:
1) Identify flows and handle the mapping between a certain multi-connection service to one or more
connections across heterogeneous access technologies;
2) Enforce the specific policy in each access technology according to dynamic information in such as
the handover activity, network utilization, and access aggregation for multi-connection service;
3) Report dynamic traffic load information to MC-FE;
4) Maintain the mapping of resource identifiers among flow ID, access network ID, interface ID.

6.2.3 Service control function (SCF)
The service control function includes the resource control, registration, and authentication and authorization
functions at the service level for both mediated and non-mediated services. It supports service initiation,
release, authentication, authorization, routing of service messages, etc.

The functions of SCF are:
1) Send service control messages to appropriate MAS-F to support services and third-party
applications;
2) Receive and process service control messages;
3) Provide authentication and authorization to the requested service.

6.2.4 Multi-connection application support function (MAS-F)
The multi-connection application support function provides control capability for services accessed by
interacting with MUP-FE. It includes functions at the application level such as the service gateway (including
open API), registration and AAA for applications.
MAS-F exists between applications and SCF. By using MAS-F, applications can utilize the capability of multi-
connection (e.g., bandwidth converge, low time delay, high security, efficient utilization of network
resources, load balancing, reliability of connection and continuity of services, etc.).

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