Since P-GW/S-GW support non-standard based DSCP marking, there is a conflict when both standard based PPD feature and non-standard based user-datagram packet DSCP configuration is enabled. To avoid this conflict:

• APN and service level configuration is ignored if PPD feature is enabled.

• S-GW/P-GW can alter the outer GTP-U header DSCP value, even if PPD feature is enabled.

• User-datagram packet DSCP value is unaltered by ECS, P-GW, and S-GW if PPD feature is enabled.

• At P-GW, APN-level configuration is added to enable/disable the PPD feature.

• At S-GW, service-level configuration is added to enable/disable the PPD feature. This is to send DSCP in Paging and Service Information IE of all the DDN messages triggered by either IMS-PDN or Internet-PDN, etc.

  Important

  It is up to MME/S4-SGSN to use the Paging and Service Information IE of DDN message.

• Separate Paging feature and PPD feature co-exist in system. That means, if both features are enabled, both Paging and Service Information IE and Separate-paging IE are sent in DDN.

• Currently on P-GW, the DSCP configuration is getting applied at sub-session level during call setup time. So, when the PPD CLI is enabled for P-GW, it is applicable for new calls.

• Currently on S-GW, the DSCP configuration is getting applied at S-GW service level. So, when PPD CLI is enabled in S-GW service, it is applicable for both new and existing calls.

• Once the PPD CLI is enabled, it exists even after Session Recovery and ICSR switch over.

• The Paging and Service Information IE is used to carry per bearer paging and service information.

PPD is a license enabled feature. S-GW Paging Profile license key is required to enable PPD functionality for P-GW, S-GW, and SAEGW.

Important

Contact your Cisco account representative for information on how to obtain a license.

S-GW

When S-GW supports the PPD feature, it shall include new Paging and Service Information IE in the Downlink Data Notification message triggered by the arrival of downlink data packets at the S-GW. The Paging Policy Indication value within this IE will contain the value of the DSCP in TOS (IPv4) or TC (IPv6) information received in the IP payload of the GTP-U packet from the P-GW.

At S-GW, service-level configuration enables/disables the PPD feature. Once the PPD is configured, the feature is enabled and applicable for both existing and new calls.

P-GW

User-datagram packet DSCP value is unaltered by P-GW for downlink data. The PPD feature is supported only for S5/S8 interface. For all Handoff scenarios from other interface to S5/S8 interface, the PPD feature will get enabled if APN had it during its call setup time at that interface.

At P-GW, APN-level configuration enables/disables the PPD feature. If PPD feature is enabled for the call and handoff happens from S5/S8 interface to any other interface, PPD feature should get disabled. Now, if handoff happens and this call will come back to S5/S8 interface, PPD feature should become enabled.

SAEGW

To support PPD feature in SAEGW, both S-GW and P-GW configuration is required.

• The PPD feature is license controlled under the license for S-GW Paging Profile. Once the license is enabled, both features co-exist together and work independently. That means, DDN message might carry both DSCP marking specified by PPD feature and Priority DDN value specified by S-GW Paging Profile feature.

• At S-GW, the user-datagram packet DSCP value is used to send in DDN. S-GW can't change the DSCP, as per the local configuration (APN profile or service level). At eNodeB, the scheduling of the packet is based on the QCI instead of DSCP, however, any EPC node should not change/modify the inner DSCP value.

• If the PPD feature is enabled, none of the EPS nodes should change the user-datagram packet DSCP value. Therefore, ECS should avoid overwriting DSCP value of user-datagram packet when PPD is enabled.

The PPD functionality complies with the following standards:

• 29.274, CR-1565, "Paging Policy Indication in Downlink Data Notification Message"

• 23.401, CR-2731 "Paging policy differentiation for IMS voice"

Enabling on P-GW

The following CLI commands are used to manage the functionality for the PPD feature.

The following command enables the PPD feature on P-GW at APN level.

configure 
      context context_name  
          apn apn_name 
                   paging-policy-differentiation 
                   end 

Enabling on S-GW

The following command enables the PPD feature on S-GW at service level.

configure 
      context context_name  
          sgw-service service_name 
                   paging-policy-differentiation 
                   end 

Notes:

• This is to send DSCP in Paging and Service Information IE of all the DDN messages triggered by either IMS-PDN or Internet-PDN, etc.

• It is up to MME/S4-SGSN to use the Paging and Service Information IE of DDN message.

• If PPD feature is enabled at S-GW service, it is applicable for all calls irrespective of the APN profiles.

Disabling on P-GW

The following command disables the PPD feature on P-GW at APN level.

configure 
      context context_name  
          apn apn_name 
                   no paging-policy-differentiation 
                   end 

Disabling on S-GW

The following command disables the PPD feature on S-GW at service level.

configure 
      context context_name  
          sgw-service service_name 
                   no paging-policy-differentiation 
                   end 

This section provides information regarding P-GW show commands and/or their outputs in support of the PPD feature.

This section provides information regarding SAEGW show commands and/or their outputs in support of the PPD feature.

This section provides information regarding S-GW show commands and/or their outputs in support of the PPD feature.