Page 323 - 5G Basics - Core Network Aspects

Core network aspects 1

FSC rules is used, the MUE can also control traffic routing outside the multi-connection access control
functional entity.

The MUE can request to move selected IP flows from one access to another access by sending routing rules
to the network. These routing rules specify the selected IP flows and the new (target) access.

The network cannot request FSC. The network may reject FSC requests from MUE due to subscription (or
quota) limitations. When the network rejects an IP flow mobility request, the network shall provide to the
MUE a specific cause value indicating why the request was rejected. This cause value may be used by the
MUE to determine when and if this FSC operation can be requested again.
7.2.3 Network-initiated FSC mode

In the network-initiated FSC mode, the network controls the traffic routing within the multi-connection
access control function entity.

The network can request to move selected IP flows from one multi-connection access to another multi-
connection access by sending routing rules to the MUE. The routing rules specify the selected IP flows and
the new (target) connection.

The MUE may reject (e.g., due to the local operating environment information) a FSC request from the
network. When the MUE rejects a FSC request from the network, the MUE shall provide a cause value
indicating the reason of the rejection. The cause value may be used by the network to determine when/if
this FSC operation can be requested again.
The MUE cannot request IP flow mobility. However, the MUE can indicate to the network when an access for
multi-connection purposes can or cannot be used for traffic routing. For instance, in the case where the MUE
wants to request a mapping of IP flows to a specific access type, the MUE provides the requested mapping
to the network. However, this is not considered a routing rule provision, since the network is considered as
the decision point for routing rules in the network-initiated FSC mode. The network then provides new or
updated routing rules to the MUE, based on the request received from the MUE, unless the request is
contrary to what is allowed by the subscription.

7.2.4 Mode selection
Multi-connection FSC can operate in one of the following modes:
– MUE-initiated mode;

– Network-initiated mode.
The multi-connection FSC mode is selected with the following procedure:
– When an FSC-capable MUE supports multi-connection IAS and it has a routing policy rule valid in the
operators' network, then:
• If the routing policy rule includes at least one "routing policy for FSC" rule (irrespective of its
validity), the MUE requests MUE-initiated mode and the network selects MUE-initiated mode;
• Otherwise, the MUE requests network-initiated mode and the network selects network-
initiated mode.
– When an FSC-capable MUE does not support multi-connection IAS or supports multi-connection IAS
but it does not have a routing policy rule valid in the network, then:

• The MUE requests network-initiated mode and the network selects network-initiated mode.

7.3 Capability requirements
7.3.1 FSC-enhanced MUE requirements

To support FSC, the following capabilities of the FSC-enhanced MUE are required:
– Indicate support and request FSC for MUE multi-connection;
– Request FSC mode to the network;

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