Multiple and Virtual DNN Support

Feature Summary and Revision History

Summary Data

Table 1. Summary Data

Applicable Product(s) or Functional Area

SMF

Applicable Platform(s)

SMI

Feature Default Setting

Disabled – Configuration Required

Related Changes in this Release

Not Applicable

Related Documentation

Not Applicable

Revision History

Table 2. Revision History
Revision Details Release

Added support for IPv6 interface ID generation based on SBI VIP address and CommonId of the subscriber.

2021.01.1

SMF supports the maximum limit of 2048 for the following configurations:

  • Precedence

  • Operator policy

  • DNN policy

  • DNN profile

2021.01.0

SMF supports case insensitive DNN configuration.

2020.02.5.t1

First introduced.

Pre-2020.02.0

Feature Description


Important

The PGW-C term used in this chapter denote the EPS interworking functionality supported by SMF and must not be assumed as a standalone P-GW that is used in the LTE network.

The multi-DNN support enables the SMF to have multiple PDN connections for end users to provide different services including Internet and VoNR services.

The SMF fetches the locally configured profile-based Data Network Name (DNN) in PDU Session Establishment Request from the AMF. Then, the SMF maintains the PDN connections based on using SUPI and PDU Session ID. The SMF includes the received DNN in all SBI interfaces to authorize the end user to fetch subscription information, policy, and charging related information. The SMF provisions the forward path information to the UPF. The SMF integrates the multi-DNN support with the IP Address Management (IPAM) module to allocate address to the end user based on received DNN. The SMF maps the DNN profile that is derived from subscriber policies. The SMF also fetches DNN and IPv4 and IPv6 path information based on IPAM pool configuration and updates the UPF as part of node association interactions.


Note

Multiple DNN is supported only for 5GS procedures and is not qualified for EPS Session using SBI interfaces.

The SMF supports virtual DNN mapping based on a subscriber profile. It supports mapping of a UE-requested DNN to a configured DNN and sends the selected DNN profile towards the configured network interfaces.

DNN Case Insensitive Support

The DNN configuration in SMF is case insensitive. The configuration accepts a string from 1 through 62 alphanumeric characters, that is case insensitive. It can also contain dots (.) and/or dashes (-).

This feature is extended to support all DNN configurations and validations.

How It Works

The DNN profile lookup is based on subscriber policy or DNN policy. You can associate these policies in the SMF profile configuration. The subscriber policy has a higher precedence over the DNN policy when both the configurations are available.

The subscriber policy consists of a list of precedence values. The selection of precedence is based on various values. For example, the subscriber SUPI, GPSI, Serving PLMN, NSSAI, Charging Characteristics, and IMSI. Each precedence has an associated operator policy and the DNN policy is chosen from the selected operator policy.

The DNN policy can have a DNN profile configuration for each UE-requested DNN. The DNN profile has a Virtual or Mapped DNN with its list of interfaces.

The order of selection for a Virtual DNN is as follows:

  • Based on subscriber policy, the order of selection is as follows: smf-profile > smf-service > subscriber-policy > precedence > operator-policy > dnn-policy > dnn-profile (based on UE-requested DNN) > Virtual DNN mapping.

  • Based on the DNN policy, the order of selection is as follows: smf-profile > dnn-policy > dnn-profile (based on UE-requested DNN) > Virtual DNN mapping.

PCF, CHF, UDM, UPF, and Resource Manager (RMGR) are the supported interfaces for Virtual DNN mapping.

If the Virtual DNN mapping is not configured, the UE-requested DNN is used across all the interfaces.

Limitations

This feature has the following limitation:

  • The SMF includes first-configured DNN profile in "dnnSmfInfoList" of NFProfile during registration with NRF.

Configuring Virtual DNN

This section describes how to configure the Virtual DNN feature.

Configuring the Virtual DNN feature involves the following steps:

  1. Configuring Subscriber Policy

  2. Configuring Operator Policy and Associating a DNN Policy

  3. Configuring a DNN Policy

  4. Configuring a Virtual DNN under a DNN Profile

  5. Associating Subscriber Policy under the SMF Service

Configuring Subscriber Policy

To configure the subscriber policy, use the following sample configuration:

config 
   policy subscriber subscriber_policy_name 
      precedence precedence_value 


         gpsi-start-range gpsi_start_range_value 
         gpsi-stop-range gpsi_stop_range_value 
         imsi { mcc mcc_value | mnc mnc_value | msin  msin_value } 
         imsi-start-range imsi_start_value 
         imsi-stop-range imsi_stop_value 
         operator-policy operator_policy_name 
         pei-start-range pei_start_range_value 
         pei-stop-range pei_stop_range_value 
         sdt sdt_value 
         serving-plmn { mcc mcc_value | mnc mnc_value | mnc-list  mnc_list_value } 
         serving-plmn  serving_plmn_value 
         sst sst_value 
         supi-start-range supi_start_range_value 
         supi-stop-range supi_stop_range_value 
         end

NOTES:

  • precedence precedence_value: Specify the precedence value associated with the subscriber policy.

    The maximum limit for precedence is 2048.

  • gpsi-start-range gpsi_start_range_value : Specify the GPSI start range value to be associated with the subscriber policy. gpsi_start_range_value must be an integer in the range from 1000000000 through 999999999999999.

  • gpsi-stop-range gpsi_stop_range_value : Specify the GPSI stop range value to be associated with the subscriber policy. gpsi_stop_range_value must be an integer in the range from 1000000000 through 999999999999999.

  • imsi { mcc mcc_value | mnc mnc_value | msin msin_value} : Specify the IMSI value by providing the MCC, MNC, or MSIN value that is to be associated with the subscriber policy.

  • imsi-start-range imsi_start_value : Specify the IMSI start range value. imsi_start_value must be an integer in the range from 1000000000 through 999999999999999.

  • imsi-stop-range imsi_stop_value : Specify the IMSI stop range value. imsi_stop_value must be an integer in the range from 1000000000 through 999999999999999.

  • operator-policy operator_policy_name : Specify the operator policy to be associated with the subscriber policy.

    The maximum limit for operator policy is 2048.

  • pei-start-range pei_start_range_value : Specify the PEI start range value. pei_start_range_value must be an integer in the range from 1000000000 through 999999999999999.

  • pei-stop-range pei_stop_range_value : Specify the PEI stop range value. pei_stop_range_value must be an integer in the range from 1000000000 through 999999999999999.

  • sdt sdt_value : Specify the SDT value be associated with the subscriber policy. sdt_value must be a 6-digit octet string in the [0-9a-fA-F]{6} - 000000 - ffffff format. For example, 1A2B3c.

  • serving-plmn { mcc mcc_value mnc mnc_value mnc-list mnc_list_values} : Specify the 3-digit Mobile Country Code (MCC), 2- or 3-digit Mobile Network Code (MNC), or the list of MNC values of the serving PLMN. mcc_value and mnc_value must be a string. mnc_list_values must be a string, such as [580 660].

  • sst sst_value : Specify the Slice/Service Type (SST) value. sst_value must be a 2-digit octet string in the [0-9a-fA-F]{2} - 00 to FF format. For example, A8.

  • supi-start-range supi_start_range_value : Specify the SUPI start range value. supi_start_range_value must be an integer in the range from 1000000000 through 999999999999999.

  • supi-stop-range supi_stop_range_value : Specify the SUPI stop range value. supi_stop_range_value must be an integer in the range from 1000000000 through 999999999999999.

Configuration Verification

To verify the policy-related configuration details, use one of the following commands:

show subscriber policy policy_name or show full in the policy configuration mode.

The following is an example output of the show command:

smf(config-subscriber-polSub)# show full
policy smf polSmf
precedence 1
  sst              22
  sdt              232322
  serving-plmn mcc 210
  serving-plmn mnc 90
  supi-start-range 100000000000001
  supi-stop-range  100000000000010
  gpsi-start-range 1000000000
  gpsi-stop-range  9999999999
  
  
  operator-policy  opPol1
!
!

Configuring Operator Policy and Associating a DNN Policy

To configure the operator policy, use the following sample configuration:

config 
   policy operator operator_policy_name 
      policy dnn dnn_policy_name [  [ secondary secondary_dnn_policy_name ] [   network-capability network_capability ]  ] 
      end

NOTES:

  • policy dnn dnn_policy_name [ [ secondary secondary_dnn_policy_name ] [ network-capability network_capability] ] : Specify the parameters of primary DNN policy to be associated with the operator policy. dnn_policy_name must be a string.

    • secondary secondary_dnn_policy_name : If the parameters of DNN policy to be associated with the operator policy don't match with the primary policy, specify the secondary DNN policy for fallback. secondary_dnn_policy_name must be a string.

    • network-capability network_capability : Specify the network capability configuration details for the respective operator policy that you have selected. The network_capability value must be a string.

Configuring a DNN Policy

To configure the DNN policy, use the following configuration:

config 
   policy dnn dnn_policy_name 
      dnn dnn_name profile dnn_profile_name dnn-list dnn_list 
   exit 
exit

NOTES:

  • policy dnn dnn_policy_name : Specify the DNN policy. dnn_policy_name must be an alphanumeric string.

    In releases prior to 2021.01.0: The maximum limit for DNN policy is 512.

    In 2021.01.0 and later releases, the limit for DNN policy is increased from 512 to 2048.

  • dnn dnn_name : Specify the virtual DNN profile to map with the specified network DNN profile. dnn_name must be an alphanumeric string.

  • profile dnn_profile_name : Specify the network DNN profile. dnn_profile_name must be an alphanumeric string.

    In releases prior to 2021.01.0: The maximum limit for DNN profile is 512.

    In 2021.01.0 and later releases, the limit for DNN profile is increased from 512 to 2048.

  • dnn-list dnn_list : Specify the list of DNNs supported by the UPF node.

Configuring a Virtual DNN under a DNN Profile

To configure a virtual DNN under a DNN profile, use the following sample configuration:

config 
   profile dnn profile_name 
      dnn dnn_name network-function-list [ chf | pcf | upf ] 
   profile profile_name 
   end

NOTES:

  • dnn dnn_name : Specify the DNN name. dnn_name must be an alphanumeric string.

  • network-function-list : Specify the network functions that the selected DNN profile will be sent. Supported values are chf , pcf , and upf .

Associating Subscriber Policy under the SMF Service

To associate a subscriber policy under SMF service, use the following sample configuration:

config 
   profile smf smf_profile_name 
      service name service_name 
         subscriber-policy subscriber_policy_name 
         end

NOTES:

  • subscriber-policy subscriber_policy_name : Specify the subscriber policy name. subscriber_policy_name must be an alphanumeric string.

DNN Profile Offline Mode Support

Feature Description

The Data Network Name (DNN) Profile Offline Mode Support feature allows new sessions, or subsequent messages of existing sessions, to use the updated configuration values when the DNN is in offline mode. This feature enables SMF to switch the DNN to offline mode.


Important

You must clear the subscriber sessions before switching DNN to offline mode while changing the configuration for which dynamic change is not allowed. New session requests are rejected until the DNN is changed back to online mode.

How it Works

This section describes how the DNN Profile Offline Mode Support feature works for the supported SMF configurations.

DNN Policy

DNN Policy configuration defines the DNN Profile mapping with the DNN. After the DNN to profile mapping is changed, new subscriber for the same DNN uses the updated DNN Profile. So, there is no impact on existing subscribers.

DNN Profile

DNN profile defines various parameters for a particular DNN.

The following table describes if the dynamic configuration change is allowed or if the DNN must be set to an offline mode.

Table 3. DNN Profile Configuration and its Impact During Dynamic Update
Configuration Parameters Dynamic Change Impact on Existing Sessions
DnsServers Allowed No impact
DnnInfo Allowed New values are used after database reload of the session
NetworkElementProfile Not recommended (See NOTES)
Timeout Allowed No impact
ChargingProfile Not recommended (See NOTES)
RemoteVmac Allowed No impact
PcscfProfile Allowed No impact
PpdProfile Allowed Immediate (new values are used)
DefaultSscMode Allowed No impact
DefaultPduSession Allowed No impact
AllowedPduSession Allowed No impact
QosProfile Allowed Immediate (new values are used)
UpfApn Allowed No impact
SecondaryAuthen Allowed No impact
LocalAuthorization Allowed No impact

NOTES:

  • It is recommended not to modify or delete the NetworkElementProfile and ChargingProfile configuration parameters. If the parameters are changed, then the behavior for:

    • NetworkElementProfile: Messages for the existing sessions may be sent on new servers.

    • ChargingProfile: There may be some inconsistencies related to Usage Reporting Rules (URRs) between SMF and UPF.

  • For modifying the DNN profile mapping, the DNN profile must be in the offline mode.

  • It is recommended to review the messages shown in the help string before executing the CLI commands.

  • Switch the DNN profile to an offline mode when configuring the parameters dynamically. This step avoids the network impact, which is caused by the configuration changes.

Subscriber Policy

SMF uses subscriber policy to select the operator policy based on the following options:

  • SUPI range

  • SST (Slice/Service Type)

  • IMSI range

  • GPSI

  • PEI

  • SDT (Slice Differentiator Type)

  • S-NSSAI

  • PLMN ID

Change in Subscriber Policy configuration can be applied dynamically as it has no impact on the existing sessions. SMF selects the operator policy for the new sessions based on the updated configurations.

Limitations

The following limitations apply when the DNN is in the offline mode:

  • The subsequent 5G calls for the offline DNN are rejected with the HTTP Cause - HTTP_STATUS_CODE_503_SERVICE_UNAVILABLE, and 5GSMCause as “Service option temporarily out of order”.

  • The subsequent 4G calls for the offline DNN are rejected with the GTP cause “No resources available".

Configuring the DNN Profile Offline Mode Support Feature

This section describes how to enable the offline mode for a DNN profile.

Configuring the DNN Profile to Offline Mode

To configure the DNN profile to offline mode, use the following sample configuration:

config 
  profile dnn dnn_profile_name 
    mode dnn_mode 
    end

NOTES:

  • profile dnn dnn_profile_name : Specify the DNN profile.

  • mode dnn_mode : Specify the DNN mode of operation. When the DNN mode is set to offline , the new sessions are rejected. The default value is online .

Verifying the DNN Profile Offline Mode Configuration

This section describes how to verify if the DNN profile is set to the offline mode.

The following is an example output of the show running-config profile dnn profile_name command. 


show running-config profile dnn intershat 
  profile dnn intershat
       mode offline
       network-element-profiles chf chf1
       network-element-profiles amf amf1
       network-element-profiles pcf pcf1
       network-element-profiles udm udm1
       charging-profile chgprf1
       virtual-mac b6:6d:47:47:47:47
       ssc-mode 2 allowed [ 3 ]
       session type IPV4 allowed [ IPV6 IPV4V6 ]
       upf apn intershat
       dcnr true
   exit

DNN Profile Offline Mode OAM Support

This section describes operations, administration, and maintenance information for this feature.

Bulk Statistics Support

The following label is introduced as part of this feature:

  • LABEL_DISC_PDUSETUP_DNN_OFFLINE: This label is defined to indicate that the call is rejected because the DNN is in the offline mode.

IP Pool Allocation per DNN

Feature Description

The IP Pool Allocation per DNN feature supports mapping of a UE-requested DNN to a configured DNN for IP Pool selection. This feature is supported for the SMF and PGW-C in 5G and 4G.

The IP Pool Allocation per DNN feature supports the following functionalities:

  • Enables SMF to support a new configuration under the DNN profile to enable mapping of the UE-requested DNN to a DNN that is associated with an IP pool.

  • Sends the mapped DNN over Remote Procedure Call (gRPC) to the Resource Manager functionality under Node Manager service for IP allocation.

  • Supports the new configuration for IP Pool DNN over the virtual DNN with Redundancy Manager, if available.

  • Sends the UE-requested DNN when both the new configuration for IP pool and the virtual DNN are unavailable.

How it Works

This section provides a brief of how the IP Pool Allocation per DNN feature works.

  • The DNN profile lookup is based on the subscriber policy or DNN policy. The DNN profiles are associated in the SMF profile configuration. The subscriber policy takes precedence over the DNN policy when both the configurations are present.

  • The subscriber policy contains a list of precedence values. The selection of the precedence is based on the SUPI, GPSI, serving PLMN, and NSSAI value of the subscriber.

  • Each precedence has an associated operator policy. The DNN policy is picked from the selected operator policy.

  • The DNN policy can have a DNN profile configuration for each of the UE-requested DNNs.

  • The DNN profile contains the virtual or mapped DNN with its list of interfaces. This is an existing configuration and Redundancy Manager is also in the list of interfaces. For more information, see the Configuring a Virtual DNN under a DNN Profile section.

  • The new configuration under the DNN profile contains the mapping of the UE-requested DNN to IP Pool DNN.

  • The DNN profile selection occurs in the following order:

    • Based on subscriber policy, the order of selection is as follows: smf-profile > smf-service > subscriber-policy > precedence > operator-policy > dnn-policy > dnn-profile (based on UE-requested DNN) > Virtual DNN mapping.

    • Based on the DNN policy, the order of selection is as follows: smf-profile > dnn-policy > dnn-profile (based on UE requested Dnn) > Virtual DNN mapping.


Note

  • New IP pool DNN mapping takes precedence over the existing virtual DNN configuration if the Redundancy Manager configuration exists.

  • If both the configurations for the Redundancy Manager are not present, the UE-requested DNN is used to select the IP pool.

  • If the mapped DNN does not have the IP pool configured, then IP allocation fails, and the call is deleted.

  • Both the EPS and 5G calls follow the same principles for IP allocation for a DNN.

Configuring IP Pool Allocation

This section describes how to configure the IP Pool Allocation per DNN feature.

Configuring the IP Pool Allocation per DNN involves either one of the following steps:

  1. Configuring virtual DNN under DNN profile. For more information, see the Configuring a Virtual DNN under a DNN Profile section.


    Note
    This is a generic configuration along with other interfaces as an option.

  2. Allocating the IP pool per DNN


    Note
    This configuration is specifically only for IP allocation.

Allocating the IP Pool per DNN

To allocate the IP pool per DNN, use the following sample configuration:

config 
   profile dnn dnn_profile_name 
      dnn rmgr rmgr_name 
      end

NOTES:

  • profile dnn dnn_profile_name : Map the Virtual DNN profile with the specified network DNN profile. dnn_profile_name must be an alphanumeric string.

  • dnn rmgr rmgr_name : Specifiy the Redundancy Manager to which the DNN profile will be sent. rmgr_name must be an alphanumeric string.

Verifying IP Pool Allocation Configuration

This section describes how to verify the IP pool allocation configuration.

Use the show full CLI command in the DNN Profile Configuration mode to verify the configuration associated with IP pool allocation per DNN.

The following is an example output of this show command.

[unknown] smf(config-dnn-cisco123)# show full 
profile dnn intershat
dns primary ipv4 209.165.200.231
dns primary ipv6 2001:DB8:1::1
dns secondary ipv4 209.165.200.232
dns secondary ipv6 2001:DB8:1::2
network-element-profile-list chf [ chgser1 ]
dnn starent.com network-function-list [ upf chf rmgr ]
dnn rmgr cisco.com 
charging-profile chgprf1
virtual-mac      01-00-5E-90-10-00
pcscf-profile    pcscf1
ppd-profile      ppd1
ssc-mode 1
session type IPV4
.
.
.