7.2.25 Modify Access Bearers Response

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

If an SGW supports the MABR feature (see clause 8.83), the SGW shall send a Modify Access Bearers Response message on the S11 interface to an MME as a response to a Modify Access Bearers Request message.

If handling of all default bearers to be modified fails, then Cause at the message level shall be a failure cause.

Possible Cause values are specified in Table 8.4-1. Message specific cause values are:

– "Request accepted".

– "Request accepted partially".

– "Context not found".

– "Service not supported".

– "Modifications not limited to S1-U bearers"

The SGW shall send the cause value "Modifications not limited to S1-U bearers" if

– it can not serve the MME Request without corresponding S5/S8 signalling other than to unpause charging in the PGW, or without corresponding Gxc signalling when PMIP is used over the S5/S8 interface, or

– if there are suspended non-GBR bearers for that UE in the SGW (NOTE 3).

Upon receipt of that cause value, the MME shall repeat its request using Modify Bearer Request message per PDN connection.

NOTE 1: This cause value is introduced for forward compatibility between an MME implementing this version of the specification and an SGW implementing a more recent version requiring the SGW to send S5/S8 signalling.

NOTE 2: During an Inter-MME Intra-SGW handover/TAU, if the SGW, PGW and the old MME support the partial failure handling feature but the new MME doesn’t, the SGW needs to inform the PGW about the change of FQ-CSID (see clause 16.2.5 of 3GPP TS 23.007 [17]). If the SGW receives a Modify Access Bearers Request from the new MME, it can force the MME to send individual Modify Bearer Request message per PDN connection by returning the cause value "Modifications not limited to S1-U bearers".

NOTE 3: There may be some suspended non-GBR bearers in the SGW during an Inter-MME Intra-SGW Tracking Area Update without SGW Change when the UE is coming back to E-UTRAN via a different MME than the MME serving the UE before the CSFB or SRVCC call.

Table 7.2.25-1: Information Elements in a Modify Access Bearers Response

Information elements

P

Condition / Comment

IE Type

Ins.

Cause

M

Cause

0

Bearer Contexts modified

C

EPS bearers corresponding to Bearer Contexts to be modified that were sent in Modify Access Bearers Request message. Several IEs with the same type and instance value may be included as necessary to represent a list of the Bearers which are modified.

Bearer Context

0

Bearer Contexts marked for removal

C

EPS bearers corresponding to Bearer Contexts to be removed that were sent in the Modify Access Bearers Request message. Shall be included if request message contained Bearer Contexts to be removed.

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

Bearer Context

1

Recovery

C

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

Recovery

0

Indication Flags

CO

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

Applicable flags are:

  • Associate OCI with SGW node’s identity: The SGW shall set this flag to 1 on the S11/S4 interface if it has included the "SGW’s Overload Control Information" and if this information is to be associated with the node identity (i.e. FQDN or the IP address received from the DNS during the SGW selection) of the serving SGW.

Indication

0

SGW’s node level Load Control Information

O

The SGW may include this IE, over the S11/S4 interface if the load control feature is supported by the SGW and is activated in the network (see clause 12.2.6).

When present, the SGW shall provide only one instance of this IE, representing its node level load information.

Load Control Information

0

SGW’s Overload Control Information

O

During an overload condition, the SGW may include this IE over the S11/S4 interface if the overload control feature is supported by the SGW and is activated in the network (see clause 12.3.11).

When present, the SGW shall provide only one instance of this IE, representing its overload information.

Overload Control Information

0

Private Extension

O

Private Extension

VS

Table 7.2.25-2: Bearer Context modified within Modify Access Bearers Response

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

Cause

M

This IE shall indicate if the bearer handling was successful, and if not, gives information on the reason.

Cause

0

S1-U SGW F-TEID

C

This IE shall be present on the S11 interface if S1-U is being used, i.e. if the S11-U Tunnel flag was not set in the Modify Access Bearers Request. The SGW may change the GTP-U F-TEID value if the ‘Change F-TEID support Indication’ flag was set to 1 in the Modify Access Bearers Request. Otherwise, the SGW shall return the currently allocated GTP-U F-TEID value.

See NOTE 1.

F-TEID

0

S11-U SGW F-TEID

C

This IE shall be present on the S11 interface if S11-U is being used, i.e. if the S11-U Tunnel flag was set in the Modify Access Bearers Request. If the ‘Change F-TEID support Indication’ flag was set to 1 in the Modify Bearer Request and the SGW needs to change the F-TEID, the SGW shall include the new GTP-U F-TEID value. Otherwise, the SGW shall return the currently allocated GTP-U F-TEID value.

F-TEID

1

NOTE 1: The SGW shall not change its F-TEID for a given interface during the Handover, Service Request and E-UTRAN Initiated E-RAB modification procedures.
During Handover and Service Request the target eNodeB may use a different IP type than the one used by the source eNodeB. In order to support such a scenario, the SGW F-TEID should contain both an IPv4 address and an IPv6 address (see also clause 8.22 "F-TEID").

Table 7.2.25-3: Bearer Context marked for removal within Modify Access Bearers Response

Octet 1

Bearer Context IE Type = 93 (decimal)

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

Cause

M

This IE shall indicate if the bearer handling was successful, and if not, gives information on the reason.

Cause

0

Table 7.2.25-4: Load Control Information within Modify Access Bearers Response

Octet 1

Load Control Information IE Type = 181 (decimal)

Octets 2 and 3

Length = n

Octet 4

Spare and Instance fields

Information elements

P

Condition / Comment

IE Type

Ins.

Load Control Sequence Number

M

See clause 12.2.5.1.2.1 for the description and use of this parameter.

Sequence Number

0

Load Metric

M

See clause 12.2.5.1.2.2 for the description and use of this parameter.

Metric

0

Table 7.2.25-5: Overload Control Information within Modify Access Bearers Response

Octet 1

Overload Control Information IE Type = 180 (decimal)

Octets 2 and 3

Length = n

Octet 4

Spare and Instance fields

Information elements

P

Condition / Comment

IE Type

Ins.

Overload Control Sequence Number

M

See clause 12.3.5.1.2.1 for the description and use of this parameter.

Sequence Number

0

Overload Reduction Metric

M

See clause 12.3.5.1.2.3 for the description and use of this parameter.

Metric

0

Period of Validity

M

See clause 12.3.5.1.2.2 for the description and use of this parameter.

This IE should be set to "0" if the "Overload Reduction Metric" is null. This IE shall be ignored by the receiver if the "Overload Reduction Metric" is null.

EPC Timer

0