9.9.2 Common information elements

24.3013GPPNon-Access-Stratum (NAS) protocol for Evolved Packet System (EPS)Release 18Stage 3TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

9.9.2.0 Additional information

The purpose of the Additional information information element is to provide additional information to upper layers in relation to the generic NAS message transport mechanism.

The Additional information information element is coded as shown in figure 9.9.2.0.1 and table 9.9.2.0.1.

The Additional information is a type 4 information element with a minimum length of 3 octets.

8	7	6	5	4	3	2	1
Additional information IEI								octet 1
Additional information length								octet 2
Additional information value								octets 3-n

Figure 9.9.2.0.1: Additional information information element

Table 9.9.2.0.1: Additional information information element

Additional information value (octet 3 to octet n)

The coding of the additional information value is dependent on the generic message container type.

9.9.2.0A Device properties

See clause 10.5.7.8 in 3GPP TS 24.008 [13].

9.9.2.1 EPS bearer context status

The purpose of the EPS bearer context status information element is to indicate the state of each EPS bearer context that can be identified by an EPS bearer identity.

The EPS bearer context status information element is coded as shown in figure 9.9.2.1.1 and table 9.9.2.1.1.

The EPS bearer context status information element is a type 4 information element with 4 octets length.

EPS bearer context status IEI

octet 1

Length of EPS bearer context status contents

octet 2

EBI

(7)

EBI

(6)

EBI

(5)

EBI

(4)

EBI

(3)

EBI

(2)

EBI

(1)

EBI

(0)

octet 3

EBI

(15)

EBI

(14)

EBI

(13)

EBI

(12)

EBI

(11)

EBI

(10)

EBI

(9)

EBI

(8)

octet 4

Figure 9.9.2.1.1: EPS bearer context status information element

Table 9.9.2.1.1: EPS bearer context status information element

EBI(x) shall be coded as follows:

EBI(0):

Bit 1 of octet 3 is spare and shall be coded as zero.

EBI(1) – EBI(15):

0 indicates that the ESM state of the corresponding EPS bearer context is BEARER CONTEXT-INACTIVE.

1 indicates that the ESM state of the corresponding EPS bearer context is not BEARER CONTEXT-INACTIVE

9.9.2.2 Location area identification

See clause 10.5.1.3 in 3GPP TS 24.008 [13].

9.9.2.3 Mobile identity

See clause 10.5.1.4 in 3GPP TS 24.008 [13].

9.9.2.4 Mobile station classmark 2

See clause 10.5.1.6 in 3GPP TS 24.008 [13].

9.9.2.5 Mobile station classmark 3

See clause 10.5.1.7 in 3GPP TS 24.008 [13].

9.9.2.6 NAS security parameters from E-UTRA

The purpose of the NAS security parameters from E-UTRA information element is to provide the UE with information that enables the UE to create a mapped UMTS security context.

The NAS security parameters from E-UTRA information element is coded as shown in figure 9.9.2.6.1 and table 9.9.2.6.1.

The NAS security parameters from E-UTRA is a type 3 information element with a length of 2 octets.

The value part of the NAS security parameters from E-UTRA information element is included in specific information elements within some RRC messages sent to the UE; see 3GPP TS 36.331 [22]. For these cases the coding of the information element identifier and length information is defined in 3GPP TS 36.331 [22].

8	7	6	5	4	3	2	1
NAS security parameters from E-UTRA IEI								octet 1
0	0	0	0	DL NAS COUNT value (short)				octet 2
Spare				DL NAS COUNT value (short)				octet 2

Figure 9.9.2.6.1: NAS security parameters from E-UTRA information element

Table 9.9.2.6.1: NAS security parameters from E-UTRA information element

DL NAS COUNT value (short) (octet 2, bit 1 to 4)

This field contains the 4 least significant bits of the binary representation of the downlink NAS COUNT value applicable when this information element is sent.

Bit 5 to 8 of octet 2 are spare and shall be coded as zero.

9.9.2.7 NAS security parameters to E-UTRA

The purpose of the NAS security parameters to E-UTRA information element is to provide the UE with parameters that enable the UE to create a mapped EPS security context and take this context into use after inter-system handover to S1 mode.

The NAS security parameters to E-UTRA information element is coded as shown in figure 9.9.2.7.1 and table 9.9.2.7.1.

The NAS security parameters to E-UTRA is a type 3 information element with a length of 7 octets.

The value part of the NAS security parameters to E-UTRA information element is included in specific information elements within some RRC messages sent to the UE; see 3GPP TS 36.331 [22]. For these cases the coding of the information element identifier and length information is defined in 3GPP TS 36.331 [22].

8	7	6	5	4	3	2	1
NAS security parameters to E-UTRA IEI								octet 1
Nonce_MME value								octet 2 octet 5
0 spare	Type of ciphering algorithm			0 spare	Type of integrity protection algorithm			octet 6
0	0	0	0	TSC	NAS key set identifier			octet 7
spare

Figure 9.9.2.7.1: NAS security parameters to E-UTRA information element

Table 9.9.2.7.1: NAS security parameters to E-UTRA information element

Nonce_MME value (octet 2 to 5)

This field is coded as the nonce value in the Nonce information element (see clause 9.9.3.25).

Type of integrity protection algorithm (octet 6, bit 1 to 3) and
type of ciphering algorithm (octet 6, bit 5 to 7)

These fields are coded as the type of integrity protection algorithm and type of ciphering algorithm in the NAS security algorithms information element (see clause 9.9.3.23).

Bit 4 and 8 of octet 6 are spare and shall be coded as zero.

NAS key set identifier (octet 7, bit 1 to 3) and
type of security context flag (TSC) (octet 7, bit 4)

These fields are coded as the NAS key set identifier and type of security context flag in the NAS key set identifier information element (see clause 9.9.3.21).

Bit 5 to 8 of octet 7 are spare and shall be coded as zero.

9.9.2.8 PLMN list

See clause 10.5.1.13 in 3GPP TS 24.008 [13].

9.9.2.9 Spare half octet

This element is used in the description of EMM and ESM messages when an odd number of half octet type 1 information elements are used. This element is filled with spare bits set to zero and is placed in bits 5 to 8 of the octet unless otherwise specified.

9.9.2.10 Supported codec list

See clause 10.5.4.32 in 3GPP TS 24.008 [13].