3GPP 24.501 v20.0.0 — the document's own text
9.11.2.9 S1 mode to 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 S1 mode to N1 mode NAS transparent container information element is to provide the UE with parameters that enable the UE to create a mapped 5G NAS security context and take this context into use after inter-system change to N1 mode in 5GMM-CONNECTED mode.
The S1 mode to N1 mode NAS transparent container information element is coded as shown in figure 9.11.2.9.1 and table 9.11.2.9.1.
The S1 mode to N1 mode NAS transparent container is a type 4 information element with a length of 10 octets.
The value part of the S1 mode to 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 | |
|---|---|---|---|---|---|---|---|---|
| S1 mode to N1 mode NAS transparent container IEI | octet 1 | |||||||
| Length of S1 mode to 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 | ||||||
| 0Spare | NCC | TSC | Key set identifier in 5G | octet 8 | ||||
| 0Spare | 0Spare | 0Spare | 0Spare | 0Spare | 0Spare | 0Spare | 0Spare | octet 9octet 10 |
| 0Spare | 0Spare | 0Spare | 0Spare | 0Spare | 0Spare | 0Spare | 0Spare |
Figure 9.11.2.9.1: S1 mode to N1 mode NAS transparent container information element
Table 9.11.2.9.1: S1 mode to 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). |
| NCC (octet 8, bits 5 to 7) |
| This field contains the 3 bit Next hop chaining counter (see 3GPP TS 33.501 [24]) |
| 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). |
| Octets 9 and 10 are spare and shall be coded as zero. |
| NOTE: In earlier versions of this protocol, octets 9 and 10 can have any value. In this version of the protocol, octets 9 and 10 can always be ignored by the UE. |