Page 487 - 5G Basics - Core Network Aspects

Core network aspects 1

Table 5 – Mobility location binding acknowledgement (MLM-FE(P) → UE)

Information element Explanation

Mobility service subscriber identifier The user/UE identifier authenticated for mobility services. This will be
(Note 1) the same as the transport subscriber identifier in the integrated scenario.
Persistent IP address information A set of IP address information used for locating the mobile UE
– Unique IP address The persistent IP address allocated to the attached mobile UE.

– Address realm The addressing domain in which the IP address is significant.
Anchor point address The address of the upper data tunnelling end point, from the point of
(conditionally mandatory) (Note 2) view of the UE.
Binding request result Indication of the success or failure of the binding update.
NOTE 1 – UE identifier is required if persistent address is private.
NOTE 2 – Anchor point address is required for initial tunnel installation.

6.5.4 Reference point M4 between UE and HDC-FE

This information flow is used to carry handover event or command messages between the HDC-FE and the
UE.

6.5.4.1 Initiation of handover sequence
The handover sequence begins when the UE detects that it will need to perform handover in the near future.
It alerts the HDC-FE and provides a list of alternative access points that it has detected, using the "handover
candidate indication" primitive (Table 6). The HDC-FE responds with the "handover candidate response"
(Table 7).

Table 6 – Handover candidate indication (UE → HDC-FE)

Information element Explanation

Mobility service subscriber identifier The user/UE identifier authenticated for mobility services. This will be
the same as the transport subscriber identifier in the integrated scenario.
Access point list A list of attachment point identifiers suggesting new access networks to
which handover initiation will be considered. The list is sorted from most
preferred first to least preferred last.

Preferred handover decision maker Indicates whether the UE prefers the network to select the target access
(optional) point or prefers to do the selection itself.
Preferred triggering entity (optional) Indicates whether the UE prefers the network to trigger handover or
whether the UE prefers to do so itself.

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