5 IP Flow Mobility procedures and flows

23.2613GPPIP flow mobility and seamless Wireless Local Area Network (WLAN) offloadRelease 17Stage 2TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.1 General

This clause describes the IP flow mobility procedures for different scenarios. The call flows are described in a common way for I-WLAN and EPS and the procedures which are applicable to EPS only are marked as optional and identified as not applicable to an I-WLAN mobility deployment. Furthermore the call flows do not differentiate between trusted or untrusted accesses as the IP flow mobility procedures are common as soon as the UE configures a Care-of Address.

5.2 PDN connection establishment over first access

5.2.1 General

This clause specifies the additional UE procedures when establishing a PDN connection through a 3GPP or through a WLAN access when the UE supports IP flow mobility. In these flows it is assumed that the UE has not established the PDN connection through any access yet.

NOTE: In the rest of the document the PDN connection establishment procedure is meant to be PDP context activation procedure in case of I-WLAN mobility architecture.

5.2.2 PDN connection establishment over 3GPP access

The UE performs the initial PDN connection establishment to a 3GPP access as shown in Figure 5.2.2-1. This procedure applies independently whether the UE attaches to EPS or GPRS.

Figure 5.2.2-1: PDN connection procedure over 3GPP access

1. The initial PDN establishment procedure is performed by the UE according to TS 23.401 [10] or TS 23.060 [11], depending if the PDN connection establishment is to EPS or GPRS. During this step an IPv4 address and/or an IPv6 address/prefix is assigned to the UE.

2. The UE performs HA discovery, DSMIPv6 bootstrapping and the home link detection procedure as described in TS 23.402 [3] or TS 23.327 [4].

If the UE requests the home network prefix in the Protocol Configuration Option (as in TS 23.402 [3]), the UE shall requests in the Protocol Configuration Option an indication of HA support of IP flow mobility.

If the UE obtains the home network prefix using the IKEv2 procedure, the UE shall use IKEv2 signaling to indicate IFOM support. The HA supporting IFOM shall use IKEv2 signaling to confirm the IFOM support.

If the HA does not support IFOM, the UE shall disable IFOM capabilities for that PDN connection.

The presence of ANDSF inter-system routing policies for a given PLMN may be considered by the UE as an implicit indication that the Home Agents of that PLMN support IP flow mobility. If the UE has ANDSF inter-system routing policies, the UE may skip the IKEv2 and PCO procedures to check the IFOM support of the PDN GW for the PDN GWs residing in the PLMN where the ANDSF policies are valid.

3. If the UE detects it is not on the home link, the UE sends a DSMIPv6 Binding Update (HoA, CoA, Lifetime, BID) message to the HA as specified in RFC 5555 [2] and RFC 5648 [7]. The inclusion of the BID mobility option at this stage is an indication that the UE supports IP Flow Mobility extensions. The UE may also include some FID mobility options as described in RFC 6089 [8].

NOTE: This step cannot happen in case IP flow mobility is used in EPS as 3GPP is always the home link in EPS.

4. The HA validates the BU, installs the IP flow mobility routing rules, establishes the DSMIPv6 bindings and sends a BA to the UE per RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8].

5.2.3 PDN connection establishment over WLAN

The UE performs the initial PDN connection establishment over a WLAN access as shown in Figure 5.2.3-1.

Figure 5.2.3-1: PDN connection procedure over non-3GPP access

1. The UE connects to the WLAN and configures an IPv4 address and/or an IPv6 address/prefix. Depending on the specific scenario considered the UE attaches either to a trusted WLAN, an ePDG via an untrusted WLAN or to a PDG via a I-WLAN access as specified in TS 23.402 [3] or TS 23.327 [4]. If the UE connects to PDG or ePDG, an IPv4 address and/or an IPv6 address/prefix is assigned to the UE.

2. If the UE connects to a Trusted non-3GPP access and dynamic PCC is deployed, a GW control session may be established as specified in TS 23.203 [5].

3. The UE performs HA discovery, DSMIPv6 bootstrapping and the home link detection procedure as described in TS 23.402 [3] or TS 23.327 [4].

During the home link detection procedure in IKEv2, the UE shall use IKEv2 signalling to indicate IFOM support. The HA supporting IFOM shall use IKEv2 signalling to confirm the IFOM support.

If the HA does not support IFOM, the UE shall disable IFOM capabilities for that PDN connection.

4. If the UE detects it is not on the home link, the UE sends a DSMIPv6 Binding Update (HoA, CoA, Lifetime, BID) message to the HA as specified in RFC 5555 [2] and RFC 5648 [7]. The inclusion of the BID mobility option at this stage is an indication that the UE supports IP Flow Mobility extensions. The BID mobility option contains the Binding ID of the WLAN access. The UE may also include some FID mobility options as described in RFC 6089 [8].

5. If the HA function is located in the PDN GW and dynamic PCC is deployed, the PDN GW performs an IP-CAN session establishment procedure with the PCRF as specified in TS 23.203 [5].

6. The HA validates the BU, installs the IP flow mobility routing rules, establishes the DSMIPv6 bindings and sends a BA to the UE per RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8].

5.3 Addition of an access to a PDN connection

5.3.1 General

This clause specifies the additional procedures for adding an access to an existing PDN connection over a 3GPP access or a WLAN access when the UE supports IP flow mobility. In these flows it is assumed that the UE has performed a PDN Connection establishment procedure through one access as specified in clause 5.2. Subsequently the UE attaches to a second access and starts using both accesses for the same PDN connection. As a result the UE is simultaneously connected via both accesses and a set of traffic flows are routed through one access while the remaining traffic flows are routed through the other access.

Non-roaming, home routed roaming and Local Breakout 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.

The optional interaction steps between the gateways and the PCRF in the procedures only occur if dynamic policy provisioning is deployed in EPC. These steps are never present when the solution is applied to I-WLAN mobility architecture according to TS 23.327 [4].

5.3.2 Addition of WLAN access

After successfully attachment to 3GPP access, the UE has established a PDN connection over 3GPP access as specified in clause 5.2.2. Subsequently the UE performs the WLAN attachment, and requests to establish a PDN connection using the same APN, and attempts to use both accesses for the same PDN connection simultaneously. The WLAN access may be considered as the UE’s foreign link from DSMIPv6 perspective.

Figure 5.3.2-1: Addition of WLAN access to the PDN connection

The signalling flow above shows the particular case where the UE is first connected to a 3GPP access and then it requests addition of a WLAN access.

1. The UE discovers a WLAN and connects to it and configures an IPv4 address and/or an IPv6 address/prefix according to TS 23.402 [3] or TS 23.327 [4], depending whether the WLAN access is used in the context of EPC or I-WLAN mobility architecture.

2. The UE performs HA discovery, DSMIPv6 bootstrapping and DSMIPv6 home link detection procedure according to TS 23.402 [3] unless already performed in the 3GPP access.

3. The UE sends a DSMIPv6 Binding Update (HoA, CoA, Lifetime, BID, FID, flow description) message to the HA over the WLAN access. The UE may include the requested routing rules via the FID mobility option with both the routing filters and the BID (which includes the routing address) as specified in IETF RFC 5555 [2], IETF RFC 5648 [7] and RFC 6089 [8]. The UE can include more than one routing rule by including multiple FID mobility options in the Binding Update. The DSMIPv6 Binding Update also contains an indication which indicates that the home link (3GPP access) is still connected and also the BID mobility options which identify that one binding is associated with the home address (3GPP access) and the other with the Care-of-Address from the WLAN access. The UE also indicates in the Binding Update which is the default binding where the HA should route packets not matching any FID as specified in RFC 6089 [8].

4. In case the HA function is located in the PDN GW and dynamic PCC is deployed, the PDN GW sends an IP-CAN session modification request to the PCRF. In this request, the PDN GW provides the updated routing rules to the PCRF. The PCRF stores the mapping between each SDF and its routing address.

5. If the HA function is located in the PDN GW, based on the successful establishment of resources at the BBERF, the PCRF sends an acknowledgement to the PDN GW, including updated PCC rules if appropriate.

6. The HA creates a DSMIPv6 binding, installs the IP flow routing rules and sends a Binding Acknowledgment (Lifetime, HoA, CoA, BID, FID) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8], to indicate which routing rules requested by the UE are accepted.

The PDN GW may send message 6 before receiving the reply from PCRF in message 5.

7. Based on the IP-CAN session modification request (if step 4 was performed), the PCRF ensures that the relevant QoS rules for the SDFs are installed in the target BBERF. This is done by a GW control session and QoS rules provision procedure as specified in TS 23.203 [5].

8. In case the HA function is located in the PDN GW, appropriate 3GPP resource release procedures are executed for the resources associated with the flows that were moved away from the 3GPP source access. This procedure may be triggered by the PCRF via a GW control session and QoS rules provision procedure if PMIPv6 is used on S5 and it may be triggered by the PDN GW in case GTP is used on S5.

If the HA function is implemented in I-WLAN mobility, the UE may initiate GPRS resource release procedures for those resources that were moved away from the 3GPP source access, as specified in TS 23.060 [11].

5.3.3 Addition of 3GPP access

After successfully attachment to WLAN access, the UE has established a PDN connection over WLAN as specified in clause 5.2.3. As the UE detected the WLAN access is not the home link from DSMIPv6 perspective, DSMIPv6 signalling was triggered over the WLAN access.

Subsequently, as described in this clause, the UE performs the initial attachment procedure or PDN Connection establishment procedure over a 3GPP access and establishes a PDN connection using the same APN, as described in TS 23.060 [11], TS 23.401 [10] or TS 23.402 [3]. As the UE has indicated IP flow mobility during the initial attachment over WLAN, the 3GPP access attachment completion shall not trigger the DSMIPv6 binding deregistration.

Figure 5.3.3-1: Addition of 3GPP access to the PDN connection

The signalling flow above shows the particular case where the UE is first connected to a WLAN access and then it requests addition of a 3GPP access.

1. The UE discovers a 3GPP access and performs the Attach or PDN Connection establishment procedure according to TS 23.401 [10] or TS 23.060 [11]. Specifically, the UE sets the Request Type to Handover to facilitate the MME selects the same PDN GW/HA as the UE connects in WLAN Access. Since the UE has indicated IP flow mobility support during the initial attachment over WLAN, the HA shall not deregister the DSMIPv6 binding by sending a Binding Revocation Indication towards the WLAN access.

2. The UE sends a DSMIPv6 Binding Update (HoA, CoA, Lifetime, BID, FID, flow description) message to the HA over the 3GPP access. The UE may include the requested routing rules via the FID mobility option with both the routing filters and the BID (which includes the routing address) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8]. If the 3GPP access is the home link, the UE sets the ‘H’ flag in the respective BID mobility option, as specified in RFC 6089 [8]. The UE can include more than one routing rule by including multiple FID mobility options in the Binding Update. The UE also indicates in the Binding Update which is the default binding where the HA should route packets not matching any FID as specified in RFC 6089 [8].

3. In case the HA function is located in the PDN GW and dynamic PCC is deployed, the PDN GW sends an IP-CAN session modification request to the PCRF. In this request, the PDN GW provides the updated routing rules to the PCRF. The PCRF stores the mapping between each SDF and its routing address.

4. If the HA function is located in the PDN GW, based on the successful establishment of resources at the BBERF, the PCRF sends an acknowledgement to the PDN GW, including updated PCC rules if appropriate.

5. The HA sends a Binding Acknowledgment (Lifetime, HoA, CoA, BID, FID) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8], to indicate which routing rules requested by the UE are accepted.

The PDN GW/HA may send message 5 before receiving the reply from PCRF in message 4.

6. Based on the IP-CAN session modification request (if step 3 was performed), the PCRF ensures that the relevant QoS rules for the SDFs are installed in the target BBERF. This is done by a GW control session and QoS rules provision procedure as specified in TS 23.203 [5].

7. In case the HA function is located in the PDN GW, appropriate 3GPP bearer setup or modification procedures are executed for the resources associated with the flows that were moved onto the 3GPP access. This procedure may be triggered by the PCRF via a GW control session and QoS rules provision procedure if PMIPv6 is used on S5 and it may be triggered by the PDN GW in case GTP is used on S5.

If the HA function is implemented in I-WLAN mobility, the UE may initiate GPRS bearer setup or modification procedures for those resources that were moved onto the 3GPP access, as specified in TS 23.060 [11].

5.4 IP flow mobility within a PDN connection

5.4.1 General

This clause specifies the IP flow mobility procedures within a PDN connection. In these procedures the UE is assumed to simultaneously connect via a 3GPP access and a WLAN access. The UE is using both the accesses for the same PDN connection. Subsequently, the UE adds/modifies/deletes/moves between accesses IP flows using DSMIPv6 messages.

Non-roaming, home routed roaming and Local Breakout cases are supported by this procedure. The AAA proxy and vPCRF shown in Figure 5.4.2-1 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.

The optional interaction steps between the gateways and the PCRF in the procedures only occur if dynamic policy provisioning is deployed in EPC. These steps are not present when the solution is applied to I-WLAN mobility architecture according to TS 23.327 [4].

There are two scenarios, depending on UE initiates the QoS establishment in the target access or the network performs the QoS establishment when the IP flow is moved.

5.4.2 IP flow mobility within a PDN connection with network-initiated dynamic PCC

In this scenario the UE moves one or more IP flow(s) from one access to the other access and network-intiated dynamic PCC is used is used to set up or remove appropriate resources.

Figure 5.4.2-1: IP Flow Mobility and network initiated dynamic PCC

1. The UE is simultaneously connected to a 3GPP access and a WLAN access based on the procedures specified in clauses 5.2 and 5.3. Based on current routing rules some traffic is routed through the 3GPP access and some other traffic through the WLAN access.

2. The UE sends a Binding Update (HoA, BID, FID) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8] to the HA to install a new routing rule or to modify the routing address of an existing routing rule to route the respective traffic (identified by the included FID) through one particular access (identified by the included BID) or to remove an existing routing rule. In case of new routing rule with a new FID mobility option, the UE includes the routing filter description.

NOTE: The UE can send the Binding Update either from the 3GPP or from the WLAN access irrespective of which access the IP flow is moved to.

3. In case the HA function is implemented in EPC, the PDN GW sends an IP-CAN session modification request to the PCRF. In this request the PDN GW provides the updated routing rules to the PCRF. The PCRF stores the updated mapping between routing addresses and SDFs.

4. If the HA function is implemented in EPC, based on the successful establishment of resources in the WLAN access, the PCRF sends an acknowledgement to the PDN GW, including updated PCC rules if appropriate.

5. The HA sends a Binding Acknowledgment (Lifetime, HoA, BID, FID) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8], to indicate which routing rules requested by the UE are accepted.

The PDN GW/HA may send message 5 before receiving the reply from PCRF in message 4.

6. If the HA function is implemented in EPC, based on the IP-CAN session modification request, the PCRF ensures that the relevant QoS rules are installed in the target access or the relevant QoS rules are uninstalled from the source access. For non-3GPP access, this is done by a GW control session and QoS rules provision procedure as specified in TS 23.203 [5].

7. If the HA function is implemented in EPC, appropriate EPS resource release procedures are executed for those resources that were moved away from the 3GPP source access or appropriate EPS resource allocation procedures are executed for those resources that were moved onto the 3GPP access, as specified in TS 23.402 [3]. This procedure may be triggered by the PCRF via a GW control session and QoS rules provision procedure if PMIPv6 is used on S5 and it may be triggered by the PDN GW in case GTP is used on S5.

5.4.3 IP flow mobility within a PDN connection with UE-initiated resource request

In this scenario the UE requests for resources in the target access with UE-initiated procedures and when the resources are provided, the UE moves one or more IP flow(s) to the target access.

Figure 5.4.3-1: IP Flow Mobility and UE initiated resource request

2. Before moving an IP flow currently routed over WLAN to the 3GPP access, the UE requests appropriate resources in the 3GPP access. This is done as specified in clause 5.4.5 of TS 23.401 [10] or in clause 9.2.2.1.1 or 9.2.2.1.1A of TS 23.060 [11]. In this procedure the UE includes the packet filters related to the requested resources. In this step if the HA function is implemented in EPC, the PDN GW may interact with the PCRF to trigger the appropriate PCC decision. The PCRF can authorize the resource establishment but since there is no change in the routing rules provided by the PDN GW.

NOTE 1: After this step and until step 5 is performed, resources are allocated in two accesses for the same SDF.

3. The UE sends a Binding Update (HoA, BID, FID) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8] to the HA to install a new routing rule or to modify the routing address of an existing routing rule to route the respective traffic (identified by the included FID) through one particular access (identified by the included BID) or to remove an existing routing rule. In case of new routing rule with a new FID mobility option, the UE includes the routing filter description.

NOTE 2: The UE can send the Binding Update either from the 3GPP or from the WLAN access irrespective of which access the IP flow is moved to.

NOTE 3: The routing filters included in the BU can be different from the packet filters included in step 2 by the UE. QoS will be provided only based on the packet filters installed in step 2 but the UE can include different, e.g. more generic, routing filters in this operation.

4. In case the HA function is implemented in EPC, the PDN GW sends an IP-CAN session modification request to the PCRF. In this request the PDN GW provides the updated routing rules to the PCRF. The PCRF stores the updated mapping between routing addresses and SDFs.

5. If the HA function is implemented in EPC, based on the successful establishment of resources in the WLAN access, the PCRF sends an acknowledgement to the PDN GW, including updated PCC rules if appropriate.

6. The HA sends a Binding Acknowledgment (Lifetime, HoA, BID, FID) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8], to indicate which routing rules requested by the UE are accepted.

The PDN GW may send message 6 before receiving the reply from PCRF in message 5.

7. If the HA function is implemented in EPC, based on the IP-CAN session modification request, the PCRF ensures that the resources associated with the routing filters moved to the 3GPP access are released. This is done by a GW control session and QoS rules provision procedure as specified in TS 23.203 [5].

5.5 Removal of an access from a PDN connection

5.5.1 UE-initiated removal of an access from a PDN connection

In this scenario, the UE is attached to a 3GPP access and a WLAN access and is using both the accesses for the same PDN connection. Subsequently, the UE moves all IP flows associated with one access to another access and disconnects from the one access (e.g. due to loss of coverage or by an explicit detach).

Figure 5.5-1: Removal of one access from the PDN connection

1. The UE is simultaneously connected to a 3GPP access and a WLAN access based on the procedures specified in clauses 5.2 and 5.3. Based on current routing rules some IP flows are routed through the 3GPP access and some other IP flows through the WLAN access.

2. The UE decides to move all IP flows to one access and to disconnect from the other access (e.g. due to loss of coverage, based on internal trigger, based on updated policies from ANDSF).

a. If UE disconnects one access (either a home link or a foreign link) and maintains the other access which is the foreign link, the UE sends a Binding Update (Lifetime, HoA, BID) to the HA with lifetime set to 0 to remove the BID of the access it disconnects from. Or, alternatively, the UE sends a Binding Update (HoA, BID) over the maintained foreign link to the HA with lifetime set to non-zero, the BID of the maintained foreign link, and "O" flag set.

b. If the UE disconnects the WLAN access which is a foreign link and maintains only the 3GPP access which is the home link, the UE sends a Binding Update with lifetime 0 without any BID. This de-registration Binding Update can be sent from any available access.

3. In case the HA function is located in the PDN GW, the PDN GW initiates the IP-CAN session modification procedure with the PCRF. In this procedure, the PDN GW removes the routing address related to the removed BID associated with the IP-CAN session.

4. The HA sends a Binding Acknowledgment (Lifetime, HoA, BID) as specified in RFC 5555 [2], RFC 5648 [7] and RFC 6089 [8].

NOTE 1: As specified in RFC 6089 [8] the routing rules which point to a routing address which is not registered become inactive and don’t influence the routing of the packets, i.e. there is no need for the UE to change the routing rules as all packets will be anyway routed to the only existing binding.

5. If the HA function is located in the PDN GW, as part of the IP-CAN session modification procedure initiated in step 3, the PCRF ensures that the relevant QoS rules for the SDFs are installed in the target BBERF. This is done by a GW control session and QoS rules provision procedure as specified in TS 23.203 [5].

6. If in step 2 the UE has removed the BID associated with the 3GPP access and maintained the BID for the WLAN access, the PDN GW shall initiate the PDN GW Initiated PDN Disconnection procedure in 3GPP access as defined in TS 23.402 [3], clause 5.6.2.2 or the PDN GW Initiated Bearer Deactivation procedure as defined in TS 23.401 [10], clause 5.4.4.1. The PDN GW shall set the release cause to ‘RAT changed from 3GPP to Non-3GPP’ to avoid the MME remove the PDN GW ID from the HSS. In case of I-WLAN mobility architecture and the UE has removed the BID associated with the 3GPP access, the UE may initiate PDP Context Deactivation as described in TS 23.060 [11].

If the BID associated with the WLAN access is removed, according to TS 23.402 [3] the security associations between the UE and the HA should not be immediately deleted. As the security associations were created dynamically using IKEv2 they will be automatically deleted when they expire. Similarly, for I-WLAN mobility architecture, the H2 session between the HA and the AAA Server should not be immediately deleted. The H2 session will be deleted by the HA immediately after security associations are deleted. In case of I-WLAN mobility architecture, the UE may initiate release of the IKEv2 security association with the PDG according to TS 23.234 [9].

NOTE 2: In case a detach from 3GPP access needs to be triggered, e.g. based on O&M, a PDN GW initiated PDN disconnection procedure is used instead of a MME/SGSN-initiated detach/PDN disconnection procedure.

5.5.2 HA-initiated removal of an access from a PDN connection

In this scenario, the UE is attached to a 3GPP access and a WLAN access and is using both the accesses for the same PDN connection. The HA disconnects the UE from the one access (e.g. due to change of subscription) .

Figure 5.5-1: Removal of one access from the PDN connection

2. The HA sends a BRI message including a BID mobility option to remove only one of the binding registered for the UE as defined in IETF RFC 5846 [13].

NOTE: If HA disconnects the UE from the WLAN access and the 3GPP access is the home link, alternatively the HA can terminate the DSMIPv6 session omitting the BID mobility option.

3. The UE replies with a BRA message and removes the BID indicated by the HA as defined in IETF RFC 5846 [13].

4. In case the HA function is located in the PDN GW, the PDN GW initiates the IP-CAN session modification procedure with the PCRF. In this procedure, the PDN GW removes the routing address related to the removed BID associated with the IP-CAN session.

6. If in step 2 the HA has removed the BID associated with the 3GPP access and maintained the BID for the WLAN access, the PDN GW shall initiate the PDN GW Initiated PDN Disconnection procedure in 3GPP access as defined in TS 23.402 [3], clause 5.6.2.2 or the PDN GW Initiated Bearer Deactivation procedure as defined in TS 23.401 [10], clause 5.4.4.1. The PDN GW shall set the release cause to ‘RAT changed from 3GPP to Non-3GPP’ to avoid the MME remove the PDN GW ID from the HSS. In case of I-WLAN mobility architecture and the UE has removed the BID associated with the 3GPP access, the UE may initiate PDP Context Deactivation as described in TS 23.060 [11].

For I-WLAN mobility architecture, the H2 session between the HA and the AAA Server should not be immediately deleted. The H2 session will be deleted by the HA immediately after security associations are deleted. In case of I-WLAN mobility architecture, the UE may initiate release of the IKEv2 security association with the PDG according to TS 23.234 [9].

5.6 Addition of one access for multiple PDN connections to the same APN

When a UE having multiple PDN connections to the same APN via one access attaches to a second access, the UE needs to decide which of the multiple PDN connections the UE has would use both accesses simultaneously.

When the UE having multiple PDN connections to the same APN via a 3GPP access attaches to a WLAN, the UE shall perform DSMIPv6 procedures only for the PDN connections for which it will use IP flow mobility.

When the UE having multiple PDN connections to the same APN via the WLAN attaches to the 3GPP access, the UE should only establish the PDN connections for which it will use IP flow mobility. However, due to the restriction that the UE cannot indicate which PDN connection is to establish, the UE shall repeat UE PDN Connectivity Request until the desired PDN connections have been established and shall perform DSMIPv6 procedures for the desired PDN connections.

5.7 Detach and PDN disconnection procedures

When the UE is attached to the same PDN through two accesses and a detach or PDN disconnection procedure is required, the following considerations apply:

– In case of UE initiated PDN disconnection the UE-initiated PDN disconnection procedure described in clause 6.5.2 of TS 23.402 [3] shall be performed (in case of untrusted access the procedure described in clause 7.5.2 of TS 23.402 [3] shall be performed). When this procedure is completed, UE-initiated Detach procedure described in clause 5.3.8.2 of TS 23.401 [10] shall be performed.

– In case of HSS initiated detach, the HSS-initiated Detach procedure described in 6.5.3 of TS 23.402 [3] shall be performed (in case of untrusted access the procedure described in clause 7.5.3 of TS 23.402 [3] shall be performed). When this procedure is completed, the HSS-initiated Detach procedure described in clause 5.3.8.4 of TS 23.401 [10] shall be performed.

– In case of PDN-GW initiated PDN disconnection procedure, the procedure in clause 6.5.4 of TS 23.402 [3] shall be performed (in case of untrusted access the procedure described in clause 7.5.4 of TS 23.402 [3] shall be performed). When this procedure is completed, the PDN GW Initiated Bearer Deactivation procedure as defined in TS 23.401 [10], clause 5.4.4.1, shall be performed.

When the UE is attached to I-WLAN architecture through 3GPP and WLAN accesses and a detach or PDN disconnection procedure is required, similar considerations as above apply with reference to the procedures described in TS 23.327 [4] and TS 23.060 [11].

Annex A (informative):
Change history

Date	TSG #	TSG Doc.	CR	Rev	Subject/Comment	Old	New
06-2010	SP-48	SP-100353	–	–	MCC Update to version 2.0.0 for presentation to TSG SA for approval	1.1.0	2.0.0
06-2010	SP-48	–	–	–	MCC Update to version 10.0.0 after approval at TSG SA (Release 10)	2.0.0	10.0.0
09-2010	SP-49	SP-100547	0003	2	PDN GW capability check in IFOM	10.0.0	10.1.0
09-2010	SP-49	SP-100547	0004	–	Inter System Routing Policies	10.0.0	10.1.0
09-2010	SP-49	SP-100547	0005	–	PDN GW imitated BID removal	10.0.0	10.1.0
09-2010	SP-49	SP-100547	0007	–	Addition of the Reference and Miscellaneous corrections	10.0.0	10.1.0
03-2012	SP-55	SP-120071	0011	–	IETF reference update for TS 23.261	10.1.0	10.2.0
2012-09	–	–	–	–	Update to Rel-11 version (MCC)	10.2.0	11.0.0
2014-09	SP-65	–	–	–	Update to Rel-12 version (MCC)	11.0.0	12.0.0
2015-12	–	–	–	–	Update to Rel-13 version (MCC)	12.0.0	13.0.0
2017-03	–	–	–	–	Update to Rel-14 version (MCC)	13.0.0	14.0.0
2018-06	SP-80	–	–	–	Update to Rel-15 version (MCC)	14.0.0	15.0.0
2020-07	–	–	–	–	Update to Rel-16 version (MCC)	15.0.0	16.0.0
2022-03	SP-95E	–	–	–	Update to Rel-17 version (MCC)		17.0.0