Content for  TS 23.402  Word version:  18.3.0

This clause is related to the cases where at least one DSMIPv6 PDN disconnection procedure is performed. In case of detach the DSMIPv6 PDN disconnection is executed for all the existing PDNs connections, while in the case of disconnecting a single PDN connection the DSMIPv6 PDN disconnection is executed only for the individual PDN connection. The DSMIPv6 PDN disconnection procedure is on a per PDN basis and allows:

• the UE to inform the network that it requests to release a S2c based PDN connection; and
• the network to inform the UE that a S2c based PDN connection is disconnected.

The UE may be disconnected from a PDN either explicitly or implicitly:

• Explicit PDN disconnection: The network or the UE explicitly requests detach and signal with each other;
• Implicit PDN disconnection: The network disconnects the UE from a PDN, without notifying the UE. This is typically the case when the network presumes that it is not able to communicate with the UE, e.g. due to radio conditions.

Three PDN disconnection procedures are provided when the UE accesses the EPS through S2c:

• UE-Initiated PDN disconnection Procedure;
• AAA/HSS- initiated detach Procedure.
• PDN-GW-initiated PDN disconnection Procedure.

The PDN disconnection procedure when initiated by the UE is illustrated in Figure 7.5.2-1. In case of detaching the UE from EPS, the procedure defined in this clause must be repeated for each PDN. In the non-roaming case, none of the optional entities in Figure 7.5.2-1 are involved. The optional entities are involved in other cases. In the roaming cases, however, the 3GPP AAA Proxy relays all interaction between the 3GPP AAA Server in the HPLMN and the PDN-GW in the VPLMN.

Non-roaming (Figure 4.2.2-2), home routed roaming (Figure 4.2.3-3) and Local Breakout (Figure 4.2.3-4) cases are supported by this procedure. The AAA proxy and vPCRF are only used in the case of home routed roaming and Local Breakout. In non-roaming scenarios, the AAA proxy and vPCRF are not involved. If dynamic policy provisioning is not deployed, the optional step 3 does not occur. Instead, the PDN-GW may employ static configured policies.

The Detach procedure when initiated by the HSS/AAA is illustrated in Figure 7.5.3-1. The Detach procedure defined in this clause must be repeated for each PDN. If the HSS/AAA-initiated detach procedure has been initiated to delete the UE from the Evolved Packet Core, the HSS/AAA server shall initiate the detach procedure for each of the access systems to which the UE is registered. In the implicit detach, steps 2, 3 and 6 of Figure 7.5.3-1, are omitted.

Non-roaming (Figure 4.2.2-2), home routed roaming (Figure 4.2.3-3) and Local Breakout (Figure 4.2.3-4) cases are supported by this procedure. The AAA proxy and vPCRF are only used in the case of home routed roaming and Local Breakout. In non-roaming scenarios, the AAA proxy and vPCRF are not involved. If dynamic policy provisioning is not deployed, the optional step 4 does not occur. Instead, the PDN-GW may employ static configured policies.

The PDN Disconnection procedure when initiated by the PDN-GW is illustrated in Figure 7.5.4-1.

Non-roaming (Figure 4.2.2-1), home routed roaming (Figure 4.2.3-2) and Local Breakout (Figure 4.2.3-4) cases are supported by this procedure. The 3GPP AAA proxy and vPCRF are only used in the case of home routed roaming and Local Breakout. In non-roaming scenarios, the 3GPP AAA proxy and vPCRF are not involved. If dynamic policy provisioning is not deployed, the optional step 3 does not occur. Instead, the PDN-GW may employ static configured policies. static configured policies. If the PDN-GW-initiated PDN Disconnection Procedure is triggered by the UE binding lifetime expiration (Implicit PDN disconnection procedure), steps 1 and 2 may be omitted.