Octets

8

7

6

5

4

3

2

1

1 to 2

Type = 19 (decimal)

3 to 4

Length = n

5

Cause value

0

Reserved.

Shall not be sent and if received the Cause shall be treated as an invalid IE

Acceptance in a response

1

Request accepted (success)

"Request accepted (success)" is returned when the PFCP entity has accepted a request.

2

More Usage Report to send

This cause shall be returned by the UP function in the PFCP Session Deletion Response message when it has more usage reports to send. (See clause 5.2.2.3.1)

3

Request partially accepted

This cause shall be returned if the PSUCC feature is supported by the CP function and the UP function, when a PFCP Session Establishment Request or PFCP Session Modification Request is partially accepted. See clause 5.2.9.

4-63

Spare.

This value range shall be used by Cause values in an acceptance response message. See NOTE 1.

Rejection in a response

64

Request rejected (reason not specified)

This cause shall be returned to report an unspecified rejection cause

65

Session context not found

This cause shall be returned, if the F-SEID included in a PFCP Session Modification/Deletion Request message is unknown.

66

Mandatory IE missing

This cause shall be returned when the PFCP entity detects that a Mandatory IE is missing in a request message

67

Conditional IE missing

This cause shall be returned when the PFCP entity detects that a Conditional IE is missing in a request message.

68

Invalid length

This cause shall be returned when the PFCP entity detects that an IE with an invalid length in a request message

69

Mandatory IE incorrect

This cause shall be returned when the PFCP entity detects that a Mandatory IE is incorrect in a request message, e.g. the Mandatory IE is malformated or it carries an invalid or unexpected value.

70

Invalid Forwarding Policy

This cause shall be used by the UP function in the PFCP Session Establishment Response or PFCP Session Modification Response message if the CP function attempted to provision a FAR with a Forwarding Policy Identifier for which no Forwarding Policy is locally configured in the UP function.

71

Invalid F-TEID allocation option

This cause shall be used by the UP function in the PFCP Session Establishment Response or PFCP Session Modification Response message if the CP function attempted to provision a PDR with a F-TEID allocation option which is incompatible with the F-TEID allocation option used for already created PDRs (by the same or a different CP function) and the Restoration Indication bit was not set to "1" in the request.

72

No established PFCP Association

This cause shall be used by the CP function or the UP function if they receive a PFCP message other than the PFCP Association Setup Request and the Heartbeat Request message from a peer with which there is no established PFCP Association.

73

Rule creation/modification Failure

This cause shall be used by the UP function if a received Rule failed to be stored and be applied in the UP function.

74

PFCP entity in congestion

This cause shall be returned when a PFCP entity has detected node level congestion and performs overload control, which does not allow the request to be processed.

75

No resources available

This cause shall be returned to indicate a temporary unavailability of resources to process the received request. This cause may also be returned in Partial Failure Information to report that a rule cannot be applied due to a limitation of resources in the UP function.

76

Service not supported

This cause shall be returned when a PFCP entity receives a message requesting a feature or service that is not supported.

77

System failure

This cause shall be returned to indicate a system error condition.

78

Redirection Requested

This cause may be returned to indicate a request to the UPF to redirect its PFCP request to a different SMF.

79

All dynamic addresses are occupied

This cause may be returned if the UE IP address is to be assigned by the UP function but all UE IP addresses configured for a given Network Instance and/or IP address pool in the UP function are occupied.

80

Unknown Pre-defined Rule

This cause may be returned in Partial Failure Information to report that a pre-defined rule cannot be applied since being unknown to the UP function.

81

Unknown Application ID

This cause may be returned in Partial Failure Information to report that a rule cannot be applied due to the Application ID being unknown by the UP function.

82

L2TP tunnel Establishment failure

This cause shall be returned if the UP function detects an L2TP tunnel failure in the PFCP Session Establishment Response.

83

L2TP session Establishment failure

This cause shall be returned if the UP function detects an L2TP session failure in the PFCP Session Establishment Response.

84

L2TP tunnel release

This cause may be returned by the UP function when the L2TP tunnel is released, e.g. in a PFCP Session Report Request message to delete the PFCP session if the corresponding L2TP session is terminated since to the LNS initiated the release of the L2TP tunnel or the LNS is failed. See clause 5.31.3.

85

L2TP session release

This cause may be returned by the UP function when the L2TP session is released, e.g. in a PFCP Session Report Request message to delete the PFCP session if the corresponding L2TP session is terminated since the LNS initiated the release of the L2TP session. See clause 5.31.3.

86

PFCP session restoration failure due to requested resource not available

This cause should be returned by:

– the UP function when the CP function requests the UP function to re-establish an existing PFCP session (i.e. the Restoration Indication bit set to "1" in the request) but the GTP-U F-TEID or UE IP address provided by the CP function is not available. See clauses 4.3.2 and 4.3.4 of 3GPP TS 23.527 [40].

– the MB-UPF when the MB-SMF requests the MB-UPF to re-establish an existing PFCP session (i.e. the MBS Restoration Indication bit is set to "1" in the request) but the N3mb/N19mb LL SSM address or N6mb/Nmb9 ingress tunnel address provided by the MB-SMF is not available. See clause 8.2.2 of 3GPP TS 23.527 [40].

The resource is not available means that it cannot be assigned to any PFCP session, due to e.g. the address having been decommissioned by OAM from the (MB-) UPF or e.g. the address being no longer operational due to a partial hardware failure at the (MB-)UPF.

87 to 255

Spare for future use in a response message. See NOTE 2.

This value range shall be used by Cause values in a rejection response message. See NOTE 2.

NOTE 1: This value is or may be used in future version of the specification. If the receiver cannot comprehend the value, it shall be interpreted as an unspecified acceptance cause. Unspecified/unrecognized acceptance cause shall be treated in the same ways as the cause value 1 " Request accepted (success)".

NOTE 2: This value is or may be used in a future version of the specification. If the receiver cannot comprehend the value, it shall be interpreted as an unspecified rejection cause. Unspecified/unrecognized rejection cause shall be treated in the same ways as the cause value 64 "Request rejected (reason not specified)".