IMSI

C

This IE shall be included by the MME/SGSN if the SGW that the MME/SGSN selects for indirect data forwarding is different from the SGW already in use for the UE as the anchor point except for the case:

– If the UE is emergency or RLOS attached and the UE is UICCless

When the IMSI is included in the message, it is not used as an identifier

– if UE is emergency or RLOS attached but IMSI is not authenticated.

See NOTE1.

IMSI

0

ME Identity (MEI)

C

This IE shall be included by the MME/SGSN if the SGW that the MME/SGSN selects for indirect data forwarding is different from the SGW already in use for the UE as the anchor point and if one of the following condition is satisfied:

– If the UE is emergency or RLOS attached and the UE is UICCless; or

– If the UE is emergency or RLOS attached and the IMSI is not authenticated

MEI

0

Indication Flags

CO

This IE shall be included if any one of the applicable flags is set to 1.

Applicable flags are:

• Unauthenticated IMSI: This flag shall be set to 1 if the IMSI present in the message is not authenticated and is for an emergency or RLOS attached UE.
• Indirect Data Forwarding with UPF Indication: This flag shall be set to 1 if indirect data forwarding is required for user plane routes from UPF in the 5GS to EPS handover procedure or to UPF in the EPS to 5GS handover procedure. This flag shall not be set to 1 if indirect data forwarding is used for other mobility procedures. See NOTE 2.

Indication

0

Sender F-TEID for Control Plane

C

This IE shall be included by the MME/SGSN if the SGW that the MME/SGSN selects for indirect data forwarding is different from the SGW already in use for the UE as the anchor point.

See NOTE1.

F-TEID

0

Bearer Contexts

M

Several IEs with this type and instance value may be included as necessary to represent a list of Bearers

Bearer Context

0

Recovery

CO

This IE shall be included if contacting the peer for the first time.

Recovery

0

Private Extension

O

Private Extension

VS

NOTE 1: The SGW which is hosting the UE’s bearer(s) is considered as the (local) anchor point. Unlike the PGW, the SGW may change due to mobility between eNodeBs, or E-UTRAN and GERAN/UTRAN supported with S4 based architecture. In these cases the new SGW where the UE’s bearer(s) are moved, becomes the new local anchor point. A source MME/SGSN may select an SGW for indirect data forwarding which is different than the source (anchor) SGW. Similarly, a target MME/SGSN may select an SGW for indirect data forwarding which is different than the target (anchor) SGW.

NOTE 2: When indirect data forwarding for user plane routes from/to UPF is indicated, the SGW may select subnet(s) other than S1-u to create indirect data forwarding tunnel, e.g. based on local configuration.

Octets 2 and 3

Length = n

Octet 4

Spare and Instance fields

Information elements

P

Condition / Comment

IE Type

Ins.

EPS Bearer ID

M

EBI

0

eNodeB F-TEID for DL data forwarding

C

Target eNodeB F-TEID.

This IE shall be present in the message sent from the target MME to the SGW selected by the target MME for indirect data forwarding, or shall be included in the message sent from the source SGSN/MME to the SGW selected by the source MME for indirect data forwarding if the eNodeB F-TEID for DL data forwarding is included in the Forward Relocation Response message.

F-TEID

0

CO

Target eNodeB F-TEID.

This IE shall be present in the message sent from the target MME to the SGW selected by the target MME for indirect data forwarding of the DL data buffered in the old SGW during a TAU with SGW change procedure and data forwarding, without Control Plane CIoT EPS optimisation, as specified in clause 5.3.3.1A of 3GPP TS 23.401 [3].

SGW/UPF F-TEID for DL data forwarding

C

Target SGW F-TEID

This IE shall be present in the message sent from the source MME/SGSN to the SGW selected by the source MME for indirect data forwarding if SGW F-TEID for DL data forwarding is included in the Forward Relocation Response message. This F-TEID is assigned by the SGW that the target MME/SGSN selects for indirect data forwarding.

F-TEID

1

CO

Target UPF F-TEID

This IE shall be present in the message sent from the source MME to the SGW selected by the source MME for indirect data forwarding if SGW/UPF F-TEID for DL data forwarding is included in the Forward Relocation Response message. This IE contains the target V-UPF F-TEID in home routed roaming scenario, or containes the PGW-U+UPF F-TEID in non-roaming or local breakout scenario.

SGSN F-TEID for DL data forwarding

C

Target SGSN F-TEID

This IE shall be present in the message sent from the target SGSN to the SGW selected by the target SGSN for indirect data forwarding in E-UTRAN to GERAN/UTRAN inter RAT handover with SGW relocation procedure, or shall be included in the message sent from the source MME to the SGW selected by the source MME for indirect data forwarding if the SGSN F-TEID for DL data forwarding is included in the Forwarding Relocation Response message.

F-TEID

2

CO

This IE shall also be present in the message sent from the source MME to the SGW selected by the source MME for indirect data forwarding if the SGSN Address for User Traffic and the Tunnel Endpoint Identifier Data II are included in the GTPv1 Forward Relocation Response message as specified in D.3.7 of 3GPP TS 23.401 [3]. .

This IE shall also be present, when Direct Tunnel is not used, in the message sent from the target SGSN to the SGW selected by the target SGSN for indirect data forwarding of the DL data buffered in the old SGW during a RAU with SGW change procedure and data forwarding, as specified in clause 5.3.3.1A of 3GPP TS 23.401 [3].

RNC F-TEID for DL data forwarding

C

Target RNC F-TEID

This IE shall be present in the message sent from the target SGSN to the SGW selected by the target SGSN for indirect data forwarding in E-UTRAN to UTRAN inter RAT handover with SGW relocation procedure, or shall be included in the message sent from the source MME to the SGW selected by the source MME for indirect data forwarding if the RNC F-TEID for DL data forwarding is included in the Forwarding Relocation Response message.

F-TEID

3

CO

This IE shall also be present in the message sent from the source MME to the SGW selected by the source MME for indirect data forwarding if the RNC IP address and TEID are included in the RAB Setup Information and/or the Additional RAB Setup Information in the GTPv1 Forwarding Relocation Response message as specified in D.3.3 of 3GPP TS 23.401 [3].

This IE shall be present, when Direct Tunnel is used, in the message sent from the target SGSN to the SGW selected by the target SGSN for indirect data forwarding of the DL data buffered in the old SGW during a RAU with SGW change procedure and data forwarding as specified in clause 5.3.3.1A of 3GPP TS 23.401 [3].

eNodeB F-TEID for UL data forwarding

O

Target eNodeB F-TEID.

If available this IE may be present in the message, which is sent during the intra-EUTRAN HO from the target MME to the SGW selected by the target MME for indirect data forwarding, or may be included in the message sent from the source MME to the SGW selected by the source MME for indirect data forwarding if the eNodeB F-TEID for data UL forwarding is included in the Forward Relocation Response message.

F-TEID

4

SGW F-TEID for UL data forwarding

O

Target SGW F-TEID

If available this IE may be present in the message, which is sent during the intra-EUTRAN HO from the source MME to the SGW selected by the source MME for indirect data forwarding if SGW F-TEID for UL data forwarding is included in the Forward Relocation Response message. This F-TEID is assigned by the SGW that the target MME selects for indirect data forwarding.

F-TEID

5

MME F-TEID for DL data forwarding

CO

Target MME S11-U F-TEID

This IE shall be present in the message sent from the target MME to the SGW selected by the target MME for indirect data forwarding, during a TAU procedure with SGW change and data forwarding, with Control Plane CIoT EPS optimisation, as specified in clause 5.3.3.1A of 3GPP TS 23.401 [3].

F-TEID

6