Content for TS 23.161 Word version: 18.0.0

1… 5… 6… 6.2… 6.2.4 6.3… 6.3.2.2… 6.3.3… 6.3.3.2… 6.4… 6.4.2.2… 6.5… 6.5.2… 6.5.3… 6.6… 6.6.1.3… 6.6.2… 6.7… 6.7.2… 6.8…

6.6 Access becomes Unusable and Usable 6.6.1 An access of a PDN connection becomes unusable 6.6.1.1 3GPP access of the PDN connection becomes unusable in Trusted WLAN access 6.6.1.2 3GPP access of the PDN connection becomes unusable in Untrusted WLAN access
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6.6 Access becomes Unusable and Usable p. 50

6.6.1 An access of a PDN connection becomes unusable p. 50

6.6.1.1 3GPP access of the PDN connection becomes unusable in Trusted WLAN access p. 50

When the UE detects that the 3GPP access becomes unusable, the UE shall report this event to the network via WLAN access. The 3GPP access unusable procedure is used when the UE determines that the 3GPP access is not usable anymore for carrying the IP flows. The UE determines that the 3GPP link is not usable when it detects loss of 3GPP coverage, or 3GPP radio quality preventing the usage of this access based on UE implementation mechanism. This procedure is applied in Network-initiated NBIFOM mode.

Copy of original 3GPP image for 3GPP TS 23.161, Fig. 6.6.1.1-1: Procedure for 3GPP access becomes unusable for GTP S2a

Figure 6.6.1.1-1: Procedure for 3GPP access becomes unusable for GTP S2a
(⇒ copy of original 3GPP image)

Step 1.

The UE is connected simultaneously to 3GPP and TWAN accesses and establishes multiple IP flows of the same PDN connection.

Step 2.

The UE detects that the 3GPP link is not usable.

Step 3.

The UE sends the WLCP Modification Command message including a 3GPP unusable indication.

Step 4.

The TWAN sends the indication to the PDN GW within a Bearer Resource Command.

Step 5.

When the PCRF has subscribed to such notification, the PDN GW sends the indication to the PCRF.

The PCRF may update the PCC rules, e.g. by changing the Routing Access Type of PCC Rules and provide the updated PCC rules to the PDN GW. The PCRF does not provide updated PCC rules for those IP flows which are forbidden to be routed in the WLAN access.

Step 6.

The PDN GW moves all the IP flows from 3GPP to WLAN except those IP flows which are forbidden to be routed via WLAN.

The PDN GW provides updated Routing Rules to the UE based on the updated PCC rules received from PCRF.

The PDN GW may initiate dedicated bearer activation and/or modification procedure in WLAN according to if the IP flow shall be transported to new dedicated bearer or to existing bearer. The PDN GW may release the resource in the 3GPP access network for the IP flows which are moved to WLAN but does not release the access from the multi-access PDN connection. Steps 3 to 8 as per Figure 6.3.2.2.2-1 will be invoked.

6.6.1.2 3GPP access of the PDN connection becomes unusable in Untrusted WLAN access p. 51

Copy of original 3GPP image for 3GPP TS 23.161, Fig. 6.6.1.2-1: Procedure for 3GPP access becomes unusable for GTP S2b

Figure 6.6.1.2-1: Procedure for 3GPP access becomes unusable for GTP S2b
(⇒ copy of original 3GPP image)

Step 1.

The UE is connected simultaneously to 3GPP and untrusted WLAN accesses and establishes multiple IP flows of the same PDN connection.

Step 2.

The UE detects that the 3GPP link is not usable.

Step 3.

The UE sends the IKEv2 INFORMATIONAL Request message including a 3GPP unusable indication.

Step 3a.

The ePDG sends an IKEv2 INFORMATIONAL Response message to the UE.

Step 4.

The ePDG sends the indication to the PDN GW within a Bearer Resource Command.

Step 5.

When the PCRF has subscribed to such notification, the PDN GW sends the indication to the PCRF..

Step 6.

The PDN GW moves all the IP flows from 3GPP to WLAN except those IP flows which are forbidden to be routed via WLAN.

The PDN GW provides updated Routing Rules to the UE based on the updated PCC rules received from PCRF.