3GPP 24.501 v20.0.0 — the document's own text
9.11.2.6 Intra N1 mode NAS transparent container
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
The purpose of the Intra N1 mode NAS transparent container information element is to provide the UE with parameters that enable the UE to handle the 5G NAS security context after N1 mode to N1 mode handover.
The Intra N1 mode NAS transparent container information element is coded as shown in figure 9.11.2.6.1 and table 9.11.2.6.1.
The Intra N1 mode NAS transparent container is a type 4 information element with a length of 9 octets.
The value part of the Intra N1 mode NAS transparent container information element is included in specific information elements within some RRC messages sent to the UE.
NOTE: For these cases the coding of the information element identifier and length information of RRC is defined in 3GPP TS 38.331 [30].
| 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | |
|---|---|---|---|---|---|---|---|---|
| Intra N1 mode NAS transparent container IEI | octet 1 | |||||||
| Length of Intra N1 mode NAS transparent container contents | octet 2 | |||||||
| Message authentication code | octet 3octet 6 | |||||||
| Type of ciphering algorithm | Type of integrity protection algorithm | octet 7 | ||||||
| 0 | 0Spare | 0 | KACF | TSC | Key set identifier in 5G | octet 8 | ||
| Sequence number | octet 9 |
Figure 9.11.2.6.1: Intra N1 mode NAS transparent container information element
Table 9.11.2.6.1: Intra N1 mode NAS transparent container information element
| Message authentication code (octet 3 to 6) | |
|---|---|
| This field is coded as the Message authentication code information element (see clause 9.8). | |
| Type of integrity protection algorithm (octet 7, bit 1 to 4) andtype of ciphering algorithm (octet 7, bit 5 to 8) | |
| 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 9.11.3.34). | |
| K_AMF_change_flag (KACF) (octet 8, bit 5) | |
| Bit | |
| 5 | |
| 0 | a new KAMF has not been calculated by the network |
| 1 | a new KAMF has been calculated by the network |
| Key set identifier in 5G (octet 8, bit 1 to 3) andType of security context flag (TSC) (octet 8, 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 9.11.3.32). | |
| Sequence number (octet 9) | |
| This field is coded as the Sequence number information element (see clause 9.10) | |