Page 490 - 5G Basics - Core Network Aspects

1 Core network aspects

Table 13 – Access network information query response (NID-FE → UE)

Information element Explanation

Static neighbouring network info Static neighbouring network information (e.g., local policies, cost) for
networks neighbouring the serving network(s) specified in the original
query.

6.5.6 Reference point M6 between HDC-FE and L2HE-FE
This information flow is used by the HDC-FE to achieve handover at layer 2 in the forwarding plane. The
details of this information flow are technology specific and out of scope of this Recommendation.

6.5.7 Reference point M7 between HDC-FE and L3HEF
This information flow is used by the HDC-FE to achieve handover at layer 3 in the forwarding plane. The
details of this information flow are implementation specific and out of scope of this Recommendation. As a
generality, the information sent to the L3HEF will include information by which the tunnel can be identified,
the address of the other tunnel end point, and either the address given to this tunnel end point or information
from which it can be generated.
6.5.8 Reference point M8 between HDC-FE and PD-FE

Reference point M8 supports the operations described in clause 6.3.2.
6.5.8.1 Verification of resource availability

The HDC-FE queries RACF to verify that resources are available to serve the user prior to handover. For this
purpose, reference point M8 supports two primitives:

• available resource query (Table 14);
• available resource query response (Table 15).
The "available resource query" primitive is used by the HDC-FE to check with RACF in candidate networks to
verify available resources on the candidate access links.

Table 14 – Available resource query (HDC-FE → PD-FE)

Information element Explanation
Transport subscriber identifier The user/UE identifier authenticated for attachment.
Candidate attachment point list A list of attachment points, suggesting the new access networks to which
handover initiation will be considered. The access networks towards the
top of the list are preferred over those towards the bottom of the list.

Table 15 – Available resource query response (PD-FE → HDC-FE)

Information element Explanation
Transport subscriber identifier The user/UE identifier authenticated for attachment.
Status Specifies whether requested resources are available or not for each
candidate link.

6.5.8.2 Resource re-provisioning
This information flow is used by the HDC-FE to reserve session QoS resources by providing address binding
information to PD-FE, and to deallocate QoS on the old path once handover is complete. Reference point M8
supports two primitives for the purpose:

• resource re-provisioning request (Table 16);
• resource re-provisioning response (Table 17).

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