8.103 RAN/NAS Cause

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

RAN/NAS Cause is coded as depicted in Figure 8.103-1.

Bits

Octets

8

7

6

5

4

3

2

1

1

Type = 172 (decimal)

2 to 3

Length = n

4

Spare

Instance

5

Protocol Type

Cause Type

6 to m

Cause Value

(m+1) to (n+4)

These octet(s) is/are present only if explicitly specified

Figure 8.103-1: RAN/NAS Cause

The Protocol Type field shall be encoded as per Table 8.103 -0:

Table 8.103-0: Protocol Type values

Protocol Type

Values (Decimal)

S1AP Cause

1

EMM Cause

2

ESM Cause

3

Diameter Cause

4

IKEv2 Cause

5

<spare>

6-15

All spare bits shall be set to zeros by the sender and ignored by the receiver.

The Cause Value field shall be coded as follows:

– For S1-AP Cause, the Cause Value field shall contain a non-transparent copy of the cause value of the corresponding IE (see clause 8.2.2), "Cause", as defined in clause 9.2.1.3 in 3GPP TS 36.413 [10].
The Cause Type field shall contain the RAN Cause subcategory as specified in 3GPP TS 36.413 [10] and it shall be encoded as in Table 8.103-1. The value of the Cause Value field (and the associated RAN cause subcategory) is transferred over the S1-AP interface and encoded into one octet as binary integer.

Table 8.103-1: Cause Type values and their meanings

Cause Type

Values (Decimal)

Radio Network Layer

0

Transport Layer

1

NAS

2

Protocol

3

Miscellaneous

4

<spare>

5 to15

– For EMM and ESM Causes, the Cause Value field shall contain the cause value as specified respectively for the "EMM Cause" IE and "ESM Cause" IE in clauses 9.9.3.9 and 9.9.4.4 of 3GPP TS 24.301 [23], or for the "Cause" IE in clause 8.11 of 3GPP TS 24.244 [66].
The value of the Cause Value field (which has a range of 0..255) shall be transferred encoded into one octet as binary integer.
The Cause Type field shall be ignored by the receiver.

– For Diameter Cause, the Cause Value field shall contain the cause value as specified for the Diameter Termination-Cause AVP in IETF RFC 3588 [39]. The Cause Value field shall be encoded into 2 octets as binary integer of the Termination-Cause AVP value.
The currently assigned values for the Termination-Cause AVP can be found in the IANA registry for Termination-Cause AVP Values, IANA, "Termination-Cause AVP Values (code 295)", http://www.iana.org/assignments/aaa-parameters/aaa-parameters.xhtml#aaa-parameters-16.
The Cause Type field shall be ignored by the receiver.

– For IKEv2 Cause, the Cause Value field shall contain the cause value as specified for the Internet Key Exchange Version 2 (IKEv2) Parameters, Notify message error type, in IETF RFC 7296 [67]. The Cause Value field shall be encoded into 2 octets as binary integer of the IKEv2 notify message error type value.
The currently assigned values for the IKEv2 notify message error type can be found in the IANA registry for "Internet Key Exchange Version 2 (IKEv2) Parameters",
http://www.iana.org/assignments/ikev2-parameters/ikev2-parameters.xhtml#ikev2-parameters-14
The Cause Type field shall be ignored by the receiver.