7.2.24 Modify Access Bearers Request

29.2743GPP3GPP Evolved Packet System (EPS)Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C)Release 18Stage 3TS

The direction of this message shall be from MME to SGW (see Table 6.1-1).

If both the SGW and the MME support the MABR feature (see clause 8.83), an MME may send a Modify Access Bearer Request message on the S11 interface to an SGW as part of the following procedures:

– UE triggered Service Request if there is no suspended bearer for that UE,

– S1-based Handover without SGW relocation,

– X2-based handover without SGW relocation,

– Inter-MME E-UTRAN Tracking Area Update without SGW Change,

– Intra-MME E-UTRAN Tracking Area Update without SGW Change with Active Flag;

– E-UTRAN Initiated E-RAB modification procedure

– Mobile Originated Data transport in Control Plane CIoT EPS optimisation with P-GW connectivity

– Mobile Terminated Data Transport in Control Plane CIoT EPS optimisation with P-GW connectivity

– Connection Resume procedure (see clause 5.3.5A of 3GPP TS 23.401 [3])

– Establishment of S1-U bearer during Data Transport in Control Plane CIoT EPS optimisation procedure (see clause 5.3.4B.4 of 3GPP TS 23.401 [3]).

if all the following conditions are fulfilled:

– the RAT type has not changed;

– the Serving Network has not changed;

– the MME does not need to report a H(e)NB local IP address and UDP port number information change;

– the MME does not need to send UE’s location and/or User CSG information or/and UE Time Zone and/or Presence Reporting Area information to the PDN GW;

– the MME does not need to send an MME-FQ-CSID as per the requirements specified in 3GPP TS 23.007 [17];

– ISR is not activated, if the Modify Access Bearers Request is sent as part of a UE triggered Service Request;

– ISR was not activated in the old MME which is indicated by the ISRAU flag in the Context Response, if the Modify Access Bearers Request is sent as part of an Inter-MME E-UTRAN Tracking Area Update without SGW change.

– the support of ePCO has not be changed during inter MME mobility.

– Secondary RAT Usage Data Report(s) is not required to be forwarded to the PGW(s) for any active PDN Connections.

The Modify Access Bearers Request message shall include all the bearer contexts of all the PDN connections of the UE.

Support of this message is optional for the MME and SGW.

Table 7.2.24-1: Information Elements in a Modify Access Bearers Request

Information elements

P

Condition / Comment

IE Type

Ins.

Indication Flags

C

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

Applicable flags are:

  • ISRAI: This flag shall be set to 1 if ISR is established between the MME and the S4 SGSN for an S1-based Handover without SGW relocation and for an X2-based Handover without SGW relocation.
  • Change F-TEID support Indication: This flag shall be set to 1 for an IDLE state UE initiated TAU procedure to allow the SGW changing the GTP-U F-TEID.
  • S11-U Tunnel Flag: this flag shall be set to 1 on the S11 interface if user data is transported in NAS signalling.

Indication

0

Sender F-TEID for Control Plane

C

The new MME shall include this IE on the S11 interface for a TAU/Handover with MME change and without any SGW change.

If the SGW receives this IE and if it finds that its value is the same as the earlier received value of this IE for this UE, it should interpret this to mean that the MME has not changed.

F-TEID

0

Delay Downlink Packet Notification Request

C

This IE shall be sent for a UE triggered Service Request and UE initiated Connection Resume procedures. It shall contain the delay the SGW shall apply between receiving downlink data and sending Downlink Data Notification for all UEs served by that MME (see clause 5.3.4.2 of 3GPP TS 23.401 [3]).

Delay Value

0

Bearer Contexts to be modified

C

Several IEs with the same type and instance value may be included as necessary to represent a list of Bearers to be modified.

See NOTE 1.

Bearer Context

0

Bearer Contexts to be removed

C

This IE shall be included for the TAU/Handover, UE initiated Connection Resume and Service Request procedures where any of the bearers existing before the TAU/Handover procedure, UE initiated Connection Resume and Service Request procedures will be deactivated as consequence of the TAU/Handover procedure, UE initiated Connection Resume and Service Request procedures.

For the Service Request and UE initiated Connection Resume procedures, all unaccepted bearers for this UE shall be included.

For each of those bearers, an IE with the same type and instance value, shall be included.

See NOTE 1.

Bearer Context

1

Recovery

C

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

Recovery

0

Secondary RAT Usage Data Report

CO

If the PLMN has configured secondary RAT usage reporting, and if the Secondary RAT usage data is not intended for the PGW(s) for any of active PDN Connections, the MME shall include this IE on the S11 interface if it has received Secondary RAT usage data from eNodeB in an X2-based handover without Serving GW relocation, S1-based handover without MME or SGW relocation, or E-UTRAN initiated E-RAB modification procedure.

The MME shall also include this IE on the S11 interface if it has received a Secondary RAT Usage Data Report from the source MME in an S1-based handover with MME relocation but without SGW relocation.

The MME shall set the IRPGW flag to "0", to indicate that the IE shall not be forwarded to the PGW.

Several IEs with the same type and instance value may be included, to represent multiple usage data reports.

Secondary RAT Usage Data Report

0

PSCell ID

CO

The MME shall include this IE on the S11 interface, if it has received this information from the eNodeB.

PSCell ID

0

Private Extension

O

Private Extension

VS

NOTE 1: The Bearer Context to be modified IE and Bearer Context to be removed IE, together, shall contain all the bearers of all the existing PDN connections of the UE, with each bearer appearing in only one of these IEs. See clause 14 for the cases when a Bearer Context mismatch is detected.

Table 7.2.24-2: Bearer Context to be modified within Modify Access Bearers Request

Octets 1

Bearer Context IE Type = 93 (decimal)

Octets 2 and 3

Length = n

Octets 4

Spare and Instance fields

Information elements

P

Condition / Comment

IE Type

Ins.

EPS Bearer ID

M

See NOTE 1.

EBI

0

S1-U eNodeB F-TEID

C

This IE shall be sent if S1-U is being used for:

  • an UE triggered Service Request;
  • S1-based Handover without SGW relocation;
  • X2-based handover without SGW relocation;
  • in S1-U GTP-U tunnel setup procedure during an Inter-MME E-UTRAN Tracking Area Update without SGW Change procedure or Intra-MME E-UTRAN Tracking Area Update without SGW Change procedure with Active Flag (see 3GPP TS 24.301 [23]);
  • an E-UTRAN Initiated E-RAB modification procedure;
  • an UE initiated Connection Resume;
  • the Establishment of S1-U bearer during Data Transport in Control Plane CIoT EPS optimisation procedure. See NOTE 2.

If an MME is aware that the eNodeB supports both IP address types, the MME shall send both IP addresses within an F-TEID IE. If only one IP address is included, then the SGW shall assume that the eNodeB does not support the other IP address type.

F-TEID

0

S11-U MME F-TEID

CO

This IE shall be sent on the S11 interface if S11-U is being used, i.e. for the following procedures:

  • Mobile Originated Data transport in Control Plane CIoT EPS optimisation with P-GW connectivity
  • Mobile Terminated Data Transport in Control Plane CIoT EPS optimisation with P-GW connectivity

F-TEID

1

NOTE 1: If only EPS Bearer ID IE is included in the Bearer Context to be modified IE during the TAU without SGW change procedure, the SGW shall remove the stored eNodeB/MME userplane F-TEID locally.

NOTE 2: In the Establishment of S1-U bearer during Data Transport in Control Plane CIoT EPS optimisation procedure (see clause 5.3.4B.4 of 3GPP TS 23.401 [3]), the MME may send a Modify Access Bearers Request to the SGW, to request the establishment of the S1-U bearers, without sending a prior Release Access Bearers Request to tear down the S11-U bearers. In this case, the MME shall encode the bearers being switched from S11-U to S1-U in the Bearer Contexts to be modified IE and the SGW shall release the S11-U bearers upon receipt of the Modify Access Bearers Request requesting the establishment of the S1-U bearers.

Table 7.2.24-3: Bearer Context to be removed within Modify Access Bearers Request

Octets 1

Bearer Context IE Type = 93 (decimal)

Octets 2 and 3

Length = n

Octets 4

Spare and Instance fields

Information elements

P

Condition / Comment

IE Type

Ins.

EPS Bearer ID

M

EBI

0