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

First introduced.

Pre-2020.02.0

Feature Description

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 locally configured DNN profile-based DNN in PDU Session Establishment Request from the AMF and maintains the PDN connections based on using SUPI and pdu-session-id. SMF includes the received DNN in all SBI interfaces to authorize the end user to fetch subscription information, policy and charging related information and provisions forward path information to the UPF. The SMF integrates Multi-DNN Support with IPAM (IP Address Management) Module to allocate address to end-user based on received DNN, which 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 a 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.

How it Works

The DNN profile lookup is based on subscriber policy or DNN policy. They are associated in the SMF profile configuration. The subscriber policy has a higher precedence over the DNN policy when both the configurations are present.

The subscriber policy consists of a list of precedence values, and the selection of the precedence is based on the subscriber's SUPI, GPSI, Serving PLMN, and NSSAI value. Each precedence has an associated operator policy and the DNN policy is picked 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 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

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

Configuring the Virtual DNN Feature

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 DNN policy

  4. Configuring virtual DNN under DNN profile

  5. Associating subscriber policy and DNN policy under SMF profile

Configuring Subscriber Policy

To configure the subscriber policy use the following configuration:


configure 
   policy subscriber policy_name 
      precedence precedence_value operator-policy policy_name 
      end

NOTES:

  • operator-policy policy_name : Specifies the operator policy to be associated with the subscriber policy.

show full

The output of this command displays the following information based on the configuration:

  • policy subscriber policy_name

Configuring Operator Policy and Associating a DNN Policy

To configure the operator policy, use the following configuration:


configure 
   policy operator policy_name 
      policy dnn policy_name 
      end

NOTES:

  • policy dnn policy_name : Specifies the DNN policy to be associated with the operator policy.

Verifying the Configuration

This section describes how to verify the above configuration.

show full

The output of this command displays the following information based on the configuration:

  • policy subscriber policy_name

Configuring a DNN Policy

To configure the DNN policy, use the following configuration:


configure 
   policy dnn policy_name 
      dnn profile_name profile profile_name 
      profile profile_name 
      end

NOTES:

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

  • profile profile_name : Specifies the network DNN profile. profile_name must be an alphanumeric string.

Verifying the Configuration

This section describes how to verify the above configuration.

show full

The output of this command displays the following information based on the configuration:

  • policy subscriber policy_name

Configuring a Virtual DNN under a DNN Profile

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


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

NOTES:

  • dnn profile_name : Specifies the DNN profile name. profile_name must be an alphanumeric string.

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

Verifying the Configuration

This section describes how to verify the above configuration.

show full

The output of this command displays the following information based on the configuration:

  • policy subscriber policy_name

Associating Subscriber Policy under the SMF Service

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


configure 
   profile smf smf_profile_name 
      service name nsmf-pdu 
         subscriber-policy subscriber_policy_name 
         end

NOTES:

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

Verifying the Configuration

This section describes how to verify the above configuration.

show full

The output of this command displays the following information based on the configuration:

  • policy subscriber policy_name

Dynamic Configuration Change Support

Feature Description

The Dynamic Configuration Change Support feature allows new sessions, or subsequent messages of existing sessions, to use the updated configuration values.

This feature supports the following SMF configurations:

  • DNN Policy

  • DNN Profile

  • Subscriber Policy

How it Works

This section describes how dynamic change in configuration 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 the various parameters for a DNN.

The following table describes if the configuration change can be dynamically allowed or if you must set the DNN to an offline mode.

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:

  • In this release, we do not recommend changing (modify or delete) the NetworkElementProfile and ChargingProfile configuration parameters. If they are changed, the behavior for:

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

    • ChargingProfile: There may be some inconsistency between SMF and UPF related to URRs.

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

  • The SMF may report a warning when the configurations are modified. These modifications may have an impact on the ongoing calls. We recommend that you review the warning messages and take the appropriate action.

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

Subscriber Policy

Subscriber Policy is used for selecting operator policy based on SUPI range, slice information, and so on. Change in Subscriber Policy configuration can be applied dynamically as it has no impact on existing sessions. Operator policy for the new sessions are selected 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 Dynamic Configuration Change Support

This section describes how to enable dynamic configuration for the DNN Profile.

Configuring the DNN Profile to Offline Mode

Use the following command to configure the DNN Profile to offline mode.

config 
  profile dnn profile_name 
    mode offline 
    end

NOTES:

  • config : Enters the configuration mode.

  • profile dnn profile_name : Specifies the DNN profile.

  • mode : Specifies the mode of operation.

  • offline : Specifies the mode as offline.

Verifying the DNN Profile Offline Mode Configuration

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

The following configuration is a sample output of the show running-config profile dnn profile_name command: 

show running-config profile dnn intershat
profile dnn intershat
 mode offline/online [default: online]
 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

Dynamic Configuration Change OAM Support

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

Statistics

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 5GC and 4G.

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

  • Enables SMF to support the new configuration under the DNN profile to enable mapping of the UE-requested DNN to IP pool DNN.

  • Sends the mapped DNN over 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 present

  • Sends the UE-requested DNN when both the new configuration for IP pool and the virtual DNN are not present.

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 DNN.

  • 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 the 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 commands:

configure 
   profile dnn pool_name 
      dnn rmgr rmgr_name 
      end

NOTES:

  • profile dnn pool_name : Maps the specified Virtual DNN profile with the specified network DNN profile pool_name must be the name of the address pool.

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