7.9 Restoration and Recovery

29.2743GPP3GPP Evolved Packet System (EPS)Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C)Release 16Stage 3TS

7.9.0 General

Restoration and Recovery procedures are specified in 3GPP TS 23.007 [17].

7.9.1 Delete PDN Connection Set Request

This message may be sent on the S2a, S2b, S5, S8, or S11 interfaces as specified in 3GPP TS 23.007 [17].

Table 7.9.1-1: Information Elements in a Delete PDN Connection Set Request

Information elements

P

Condition / Comment

IE Type

Ins.

MME-FQ-CSID

C

This IE shall be included when a MME reports a partial fault according to the requirements in 3GPP TS 23.007 [17]. More than one FQ-CSID may appear.

FQ-CSID

0

SGW-FQ-CSID

C

This IE shall be included when a SGW reports a partial fault according to the requirements in 3GPP TS 23.007 [17]. More than one FQ-CSID may appear.

FQ-CSID

1

PGW-FQ-CSID

C

Shall be included when a PGW reports a partial fault. More than one FQ-CSID may appear

FQ-CSID

2

ePDG-FQ-CSID

C

This IE shall be included when an ePDG reports a partial fault according to the requirements in 3GPP TS 23.007 [17]. More than one FQ-CSID may appear.

FQ-CSID

3

TWAN-FQ-CSID

C

This IE shall be included when a TWAN reports a partial fault according to the requirements in 3GPP TS 23.007 [17]. More than one FQ-CSID may appear.

FQ-CSID

4

Private Extension

O

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

Private Extension

VS

TEID of 0 shall be used for the Delete PDN Connection Set Request.

Only one type of FQ-CSID shall be included in each Delete PDN Connection Set Request, A mix of different types, such as SGW-FQ-CSID and PGW-FQ-CSID shall not be used. A combined node, such as a collocated PGW/SGW, shall send separate Delete PDN Connection Set Request for the PGW role and one for the SGW role if a partial fault impacts more than one role.

7.9.2 Delete PDN Connection Set Response

This message is sent as a response to the Delete PDN Connection Set Request.

Table 7.9.2: Information Elements in a Delete PDN Connection Set Response

Information elements

P

Condition / Comment

IE Type

Ins.

Cause

M

Cause

0

Recovery

CO

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

Recovery

0

Private Extension

O

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

Private Extension

VS

TEID of 0 shall be used for the Delete PDN Connection Set Response.

The following Cause values are defined:

– "Request Accepted"

– "Request rejected"

– "System failure".

– "Mandatory IE incorrect".

– "Conditional IE missing".

– "Invalid message format".

"Request Accepted" indicates the receiving node was capable of storing a CSID value for each PDN connection for the type of node (MME, SGW, PGW, TWAN or ePDG) in the Delete PDN Connection Set Request and has marked, or will mark immediately, the PDN connections for deletion as specified in 3GPP TS 23.007 [17]. "Request Accepted" shall be returned even if there are no PDN connections that match.

"Request rejected" shall be used when the receiver of the Delete PDN Connection Set Request is not capable of storing at least one CSID value per PDN connection for the type of node (MME, SGW, PGW, TWAN or ePDG) received in the Delete PDN Connection Set Request.

The SGW shall respond to the Delete PDN Connection Set Request independently, i.e. without waiting for replies.

7.9.3 Update PDN Connection Set Request

The SGW shall send this message to the PGW on S5/S8 according to the requirements in TS 23.007 [17].

Table 7.9.3-1: Information Elements in a Update PDN Connection Set Request

Information elements

P

Condition / Comment

IE Type

Ins.

MME-FQ-CSID

C

This IE shall be included for MME relocation without SGW relocation according to the requirements in 3GPP TS 23.007 [17].

FQ-CSID

0

SGW-FQ-CSID

C

This IE shall be included for MME relocation without SGW relocation according to the requirements in 3GPP TS 23.007 [17].

FQ-CSID

1

Private Extension

O

Private Extension

VS

7.9.4 Update PDN Connection Set Response

This message is sent by the PGW to the SGW on S5/S8 in response to the Update PDN Connection Set Request message.

Table 7.9.4-1: Information Elements in a Update PDN Connection Set Response

Information elements

P

Condition / Comment

IE Type

Ins.

Cause

M

Cause

0

PGW-FQ-CSID

C

This IE shall be included for MME relocation without SGW relocation according to the requirements in 3GPP TS 23.007 [17].

FQ-CSID

0

Recovery

CO

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

Recovery

0

Private Extension

O

Private Extension

VS

The following Cause values are defined:

– "Request accepted"

– "Request rejected"

– "System failure".

– "Mandatory IE incorrect".

– "Conditional IE missing".

– "Invalid message format".

7.9.5 PGW Restart Notification

The direction of this message shall be from SGW to MME/S4-SGSN (see Table 6.1-1).

If both the SGW and the MME/S4-SGSN support the PRN feature (see clause 8.83), a PGW Restart Notification shall be sent when the SGW detects that the peer PGW has restarted, and a PGW Restart Notification may be sent when the SGW detects that the peer PGW has failed and not restarted, as specified in 3GPP TS 23.007 [17].

Table 7.9.5-1 specifies the presence of IEs in this message.

Table 7.9.5-1: Information Elements in PGW Restart Notification

Information elements

P

Condition / Comment

IE Type

Ins.

PGW S5/S8 IP Address for Control Plane or PMIP

M

IP Address

0

SGW S11/S4 IP Address for Control Plane

M

IP Address

1

Cause

CO

The SGW shall send the Cause IE with the value "PGW not responding" if it sends the PGW Restart Notification to notify that the peer PGW has failed and not restarted.

Cause

0

Private Extension

O

Private Extension

VS

7.9.6 PGW Restart Notification Acknowledge

The PGW Restart Notification Acknowledge shall be sent as a response of PGW Restart Notification to indicate that the MME/S4-SGSN deletes all the relevant PDN connections as specified in 3GPP TS 23.007 [17] if the Cause IE includes an acceptance cause.

Possible Cause values are specified in Table 8.4-1.

Table 7.9.6-1: Information Elements in PGW Restart Notification Acknowledge

Information elements

P

Condition / Comment

IE Type

Ins.

Cause

M

Cause

0

Private Extension

O

Private Extension

VS

7.9.7 PGW Downlink Triggering Notification

The direction of this message shall be from PGW to SGW and from SGW to MME(s)/S4-SGSN(s).

The PGW Downlink Triggering Notification shall be sent as part of the PGW triggered SGW restoration procedure if the MME/S4-SGSN, SGW and PGW support this optional feature as specified in 3GPP TS 23.007 [17].

Table 7.9.7-1: Information Elements in PGW Downlink Triggering Notification

Information elements

P

Condition / Comment

IE Type

Ins.

IMSI

M

IMSI

0

MME/S4-SGSN identifier

C

This IE shall be included over S5 /S11/S4 interface as specified in 3GPP TS 23.007 [17].

IP Address

0

PGW S5 F-TEID for GTP or PMIP Control Plane (NOTE 2)

O

This IE may be included over the S5 interface. If present, it shall contain the PGW S5 F-TEID value assigned during the PDN connection establishment.

(NOTE 1)

F-TEID

0

CO

The PGW shall include this IE over the S5 interface according to the conditions specified in clauses 20.2.7.1 of 3GPP TS 23.007 [17].

CO

If the SGW receives this IE it shall forward the IE to the MME/S4-SGSN over the S11/S4 interface.

This IE shall include the PGW S5 IP address for control plane and TEID for GTP based S5 case or the uplink GRE key for control plane in the PMIP based S5 case.

Private Extension

O

Private Extension

VS

NOTE 1: The SGW shall set the header TEID value in the PGW Downlink Triggering Acknowledge to the PGW’s Control Plane TEID if the ‘PGW S5 F-TEID for GTP or PMIP Control Plane’ IE is present in the PGW Downlink Triggering Notification message.

NOTE 2: In earlier versions of this specification, the name of this IE was ‘Sender F-TEID for Control Plane’. The name was changed when extending the applicability of the IE to S4/S11.

7.9.8 PGW Downlink Triggering Acknowledge

The PGW Downlink Triggering Acknowledge message shall be sent as a response to a PGW Downlink Triggering Notification message if the MME/S4-SGSN, SGW and PGW support the PGW triggered SGW restoration feature as specified in 3GPP TS 23.007 [17].

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

– "Request accepted".

– "Context not found".

Table 7.9.8-1: Information Elements in PGW Downlink Triggering Acknowledge

Information elements

P

Condition / Comment

IE Type

Ins.

Cause

M

Cause

0

IMSI

C

This IE shall be included on S11/S4 interface if the Cause is indicating the rejection value "Context Not Found" and if the MME/S4-SGSN identifier is included in the corresponding PGW Downlink Triggering Notification message.

IMSI

0

MME/S4-SGSN identifier

C

This IE shall be included on S11/S4 interface if the Cause is indicating the rejection value "Context Not Found" and if the MME/S4-SGSN identifier is included in the corresponding PGW Downlink Triggering Notification message.

IP Address

0

Private Extension

O

Private Extension

VS