Page 271 - 5G Basics - Core Network Aspects

Core network aspects 1

IV.3 IP flow mobility

a) MUE initiated IP flow mobility
When an MUE is connected simultaneously to multiple access networks, the MUE can use multiple
connections to send and receive IP flows. Because of the changes in the access network, sometimes MUE
needs to transfer one IP flow from one access network to another. In that case, MUE is required to modify
the parameters of the available connections, shown as Figure IV.3.

MUE AC-FE (1) AC-FE (2) MR-FE MC-FE MC-FE MMF
0. MUE is connected
simultaneously to multiple
access networks
1. Connection update request
2. Connection
information
3. Transport resource
modification request
4. Transport resource
modification response
5. Policy installation
6. QoS rules
7. ACK

Y.2027(12)_FIV.3

Figure IV.3 – MUE initialled IP flow mobility
0) The MUE has been connected simultaneously to multiple access networks and the MUE is using
multiple connections to send and receive IP flows;
1) MUE sends a Connection Update Request message to MR-FE. The message contains the identifier
and new information of the connection that the network wants to modify;
2) MR-FE updates the information of the connection based on the Connection Update Request
message. Then MR-FE sends a Connection Information message to MC-FE;
3) MC-FE sends a Transport Resource Modification Request message which contains the updated
information of the connections to MPC-FE;
4) MPC-FE selects new QoS policy rules for the connection based on the operator policy and the
updated connection information. Then it returns a Transport Resource Modification Response
message to MC-FE.

5) MC-FE makes and assigns related rules for access network to MMF, MMF installs the rules.
6) MMF sends the new QoS rules to AC-FE (2);
7) AC-FE (2) updates the QoS policy rules of the connection. Then it returns an ACK message to MMF.

b) Network initiated IP flow mobility
Based on current status of an access network, one of the existing IP flows is moved from one access network
to another automatically. In this case, the network is required to initiate the IP flow mobility and interact
with related functional entities directly. Figure IV.4 shows an abstract flow of network initiated IP flow
mobility.

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