7.2.14 Modify Bearer Command and Failure Indication

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

7.2.14.1 Modify Bearer Command

The Modify Bearer Command shall be sent on the S11 interface by the MME to the SGW and on the S5/S8 interface by the SGW to the PGW as part of the HSS Initiated Subscribed QoS Modification procedure, or when the SQCI flag or the PSCI flag is set to 1 in the Context Response message.

It shall also be sent on the S4 interface by the SGSN to the SGW and on the S5/S8 interface by the SGW to the PGW as part of the HSS Initiated subscribed QoS modification procedure, or when the SQCI flag or the PSCI flag is set to 1 in the Context Response message.

When deferred reporting of subscription change procedure is homogenously supported by MMEs and SGSNs in the serving network, the MME shall defer sending Modify Bearer Command if the related UE is not reachable by the MME, e.g. when the UE is suspended, when the UE has entered into power saving mode or when the PPF is cleared in the MME, until the UE becomes reachable again as specified in 3GPP TS 23.401 [3].

NOTE: SGSNs do not defer the reporting of subscription change but need to support reporting the subscription change when receiving the PSCI flag in the Context Response message.

It shall also be sent on the S2a/S2b interface by the TWAN/ePDG to the PGW as part of the HSS Initiated Subscribed QoS Modification procedure.

Table 7.2.14.1-1: Information Elements in a Modify Bearer Command

Information elements

P

Condition / Comment

IE Type

Ins.

APN-Aggregate Maximum Bit Rate (APN-AMBR)

M

This IE shall contain the APN-AMBR value received by the MME/SGSN/ TWAN/ePDG from the HSS.

AMBR

0

Bearer Context

M

Only one IE with this type and instance value shall be included and this shall represent the Default Bearer.

Bearer Context

0

MME/S4-SGSN’s Overload Control Information

O

During an overload condition, the MME/S4-SGSN may include this IE on the S11/S4 interface if the overload control feature is supported by the MME/S4-SGSN and is activated for the PLMN to which the PGW belongs (see clause 12.3.11).

When present, the MME/S4-SGSN shall provide only one instance of this IE, representing its overload information.

Overload Control Information

0

CO

If the SGW receives this IE and if it supports the overload control feature, it shall forward it to the PGW on the S5/S8 interface.

SGW’s Overload Control Information

O

During an overload condition, the SGW may include this IE over the S5/S8 interface if the overload control feature is supported by the SGW and is activated for the PLMN to which the PGW belongs (see clause 12.3.11).

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

Overload Control Information

1

TWAN/ePDG’s Overload Control Information

O

During an overload condition, the TWAN/ePDG may include this IE over the S2a/S2b interface if the overload control feature is supported by the TWAN/ePDG and is activated for the PLMN to which the PGW belongs (see clause 12.3.11).

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

Overload Control Information

2

Sender F-TEID for Control Plane

CO

The SGW shall include this IE on the S5/S8 interfaces and set it to the last value sent to the PGW.

If the Sender F-TEID for Control Plane is received, the PGW shall only handle the Modify Bearer Command message if the Sender F-TEID for Control Plane in this message is the same as the last Sender F-TEID for Control Plane received on the given interface.

F-TEID

0

Private Extension

O

This IE may be sent on the S5/S8, S4/S11 and S2a/S2b interfaces.

Private Extension

VS

Table 7.2.14.1-2: Bearer Context within Modify Bearer Command

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

This IE shall contain the default bearer ID.

EBI

0

Bearer Level QoS

C

Mandatory if other parameters than the APN-AMBR have been changed

Bearer QoS

0

CO

This IE shall also be included if the SQCI flag or PSCI flag is set to 1 in the Context Response message.

Table 7.2.14-3: Overload Control Information within Modify Bearer Command

Octet 1

Overload 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.

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

7.2.14.2 Modify Bearer Failure Indication

The Modify Bearer Failure Indication shall be sent on the S5/S8 interface by the PGW to the SGW and on the S11 interface by the SGW to the MME as part of failure of HSS Initiated Subscribed QoS Modification procedure, or when the SQCI flag or the PSCI flag is set to 1 in the Context Response message.

It shall also be sent on the S5/S8 interface by the PGW to the SGW and on the S4 interface by the SGW to the SGSN as part of failure of HSS Initiated subscribed QoS modification, or when the SQCI flag or the PSCI flag is set to 1 in the Context Response message.

It shall also be sent on the S2a/S2b interface by the PGW to the TWAN/ePDG as part of failure of HSS Initiated Subscribed QoS Modification procedure.

Cause IE indicates that an EPS bearer has not been updated in the PGW.

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

– "Context not found"

– "Service denied".

Table 7.2.14.2-1: Information Elements in a Modify Bearer Failure Indication

Information elements

P

Condition / Comment

IE Type

Ins.

Cause

M

Cause

0

Recovery

C

This IE shall be included on the S5/S8, S4/S11 and S2a/S2b interfaces 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 PGW node’s identity: The PGW shall set this flag to 1 on the S5/S8 interface or S2a/S2b interface if it has included the "PGW’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 HSS or DNS during the PGW selection) of the serving PGW. The SGW shall set this flag on the S11/S4 interface if it supports the overload control feature and if the flag is set on the S5/S8 interface.
  • 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

PGW’s Overload Control Information

O

During an overload condition, the PGW may include this IE on the S5/S8 or S2a/S2b interface, if the overload control feature is supported by the PGW and is activated for the PLMN to which the access network node, i.e. MME/S4-SGSN for 3GPP access based network, ePDG/TWAN for non-3GPP access based network, belongs (see clause 12.3.11).

When present, the PGW shall provide

  • node level overload control, in one instance of this IE; and/or
  • APN level overload control , in one or more instances of this IE, up to maximum of 10, with the same type and instance value, each representing the overload information for a list of APN(s).

See NOTE 1, NOTE 2.

Overload Control Information

0

CO

If the SGW receives this IE and if it supports the overload control feature, it shall forward it to the MME/S4-SGSN on the S11/S4 interface.

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 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

1

Private Extension

O

This IE may be sent on the S5/S8, S4/S11 and S2a/S2b interfaces.

Private Extension

VS

NOTE 1: The receiver, supporting the APN level overload information for the maximum of 10 APNs, shall handle the APN level overload information for the first 10 APNs and ignore any more APN level overload information.

NOTE 2: The APN level overload information, provided within and across different instances of the "PGW’s Overload Control Information" IE(s) shall be limited to 10 different APNs.

Table 7.2.14-2: Overload Control Information within Modify Bearer Failure Indication

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

List of Access Point Name (APN)

CO

The IE may (only) be present in the "PGW’s Overload Control Information" IE.

For indicating the APN level overload, the PGW shall include one or more instances of this IE, up to maximum of 10, with the same type and instance value, representing a list of APN(s) (sharing the same "Overload Reduction Metric").

See NOTE 1.

APN

0

NOTE 1: If more than 10 occurrences of APNs are received within one instance of the Overload Control Information IE, the receiver shall treat it as a protocol error and ignore the entire Overload Control Information IE instance.