Page 454 - 5G Basics - Core Network Aspects

1 Core network aspects

7.3 Information flows overview

This clause provides an overview of PAM service information flows. Detailed information flows are provided
in clause 9.3.
7.3.1 Overview of information flows when using the discrete PAM service number

7.3.1.1 Registration
When an AP function receives a registration request from a MS PAM function containing the SAC and the
user identity, the AP function assigns a dynamic terminal identifier (in case an analogue line is used) or a
subscriber number (in case an ISDN line is used) to that terminal and initiates a call carrying the SAC, the
request type (registration) and the terminal identifier or the subscriber number to the CCF/SSF.

The CCF/SSF uses the CLI (subscriber number) received from the user (the AP function) if it is valid; otherwise,
the CCF/SSF inserts the network provided CLI of the fixed access line to which the AP is connected, the
CCF/SSF triggers and queries the PAM-SCF for instructions.
The PAM-SCF instructs the SRF to establish a bearer connection between itself and the AP function by the
CCF/SSF.

During the registration, the following information is exchanged between the AP function and the SRF in-band
under the control of the PAM-SCF:
• The PAM-SCF instructs the SRF to request to collect the user identification information from the AP
function.
• The AP function sends the user identity to the SRF which relays the information to the PAM-SCF.
• The PAM-SCF generates the authentication data and instructs the SRF to interact with the AP
function which uses the data provided by the MS PAM function to perform the authentication.
• After finishing the registration processing, the PAM-SCF instructs the SRF to send the registration
result to the AP function in-band. The AP function sends the registration response to the MS PAM
function.
7.3.1.2 Deregistration

When an AP function receives a deregistration request from a MS PAM function or when an AP function
detects that a terminal is no longer accessible via the AP function, the AP function sends the deregistration
request by initiating a call request to CCF/SSF containing the SAC, the request type (deregistration) and the
terminal identifier (in case an analogue line is used) or the subscriber number (in case an ISDN line is used).
The CCF/SSF uses the CLI (subscriber number) received from the user (the AP function) if it is valid; otherwise,
the CCF/SSF inserts the network provided CLI of the fixed access line to which the AP is connected, and the
CCF/SSF triggers and queries the PAM-SCF for instructions.
The PAM-SCF processes the deregistration request and responses with the deregistration result to the AP
function via the SRF in-band. The AP function sends the deregistration response to the terminal if the terminal
is still accessible.

7.3.1.3 Originating call
Upon receiving an originating call request from a MS PAM function, the AP function sends an outgoing call
request to the CCF/SSF with the information containing the SAC, the request type (originating call) and the
terminal identifier (in case an analogue line is used) or the subscriber number (in case an ISDN line is used).
The CCF/SSF uses the CLI (subscriber number) received from the user (the AP function) if it is valid; otherwise,
the CCF/SSF inserts the network provided CLI of the fixed access line to which the AP is connected, and the
CCF/SSF triggers and queries the PAM-SCF for instructions.
The PAM-SCF instructs the SRF to collect the dialled number from the AP function and the AP function returns
the dialled number received from the MS PAM function to the SRF which relays the dialled number to the
PAM-SCF.

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