S-NSSAI based SMF Selection

Feature Summary and Revision History

Summary Data

Table 1. Summary Data

Applicable Product(s) or Functional Area

AMF

Applicable Platform(s)

SMI

Feature Default Setting

Enabled - Always-on

Related Documentation

Not Applicable

Revision History

Table 2. Revision History

Revision Details

Release

First introduced.

2021.04.0

Feature Description

For Custom Slice selection without NSSF, AMF now supports SMF selection based on S-NSSAIs received from UE (Requested S-NSSAI) during PDU session establishment procedures.

AMF supports SNNSAI-based SMF selection only using NRF (Network Repository Function).

During PDU session establishment procedure, AMF queries the necessary NRF serving PLMN by issuing the Nnrf_NFDiscovery_Request including SNSSAI to select SMF.

The NRF serving PLMN provides a set of the discovered SMF instances or Endpoint Addresses of SMF service instance(s) in Nnrf_NFDiscovery_Request response message. AMF uses the information provided by NRF and connects to the necessary SMF for further interactions.

Feature Configuration

To configure this feature, use the following configuration:

config 
 profile 
  network-element network_element network_element_name 
   nf-client-profile nf_client_profile_name 
   query-params query_params 
   end

NOTES:

  • network-element network_element network_element_name —Specify the peer network element and its name.

  • nf-client-profile nf_client_profile_name —Specify the NF client profile name.

  • query-params query_params —Specify the query parameter for NF discovery.

Configuration Example

The following is an example configuration.

config
 profile
  network-element smf SMF1
   nf-client-profile SMF1
   query-params [ snssais ]
   end

Configuration Verification

To verify the configuration:

show running-config profile network-element
Wed Oct  20 07:22:45.870 UTC+00:00
profile network-element smf SMF1
nf-client-profile SMF1
query-params [ snssais ]