School of Specs 24.501v20.0.0

3GPP 24.501 v20.0.0 — the document's own text

9.11.4.31 Received MBS 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 Received MBS container information element is to indicate to the UE the information of the multicast MBS sessions that the network accepts or rejects the UE to join, the information of the multicast MBS sessions that the UE is removed from, or the information of the updated MBS service area.

The Received MBS container information element is coded as shown in figure 9.11.4.31.1, figure 9.11.4.31.2, figure 9.11.4.31.3, figure 9.11.4.31.4, figure 9.11.4.31.5, figure 9.11.4.31.6, figure 9.11.4.31.7, figure 9.11.4.31.8, figure 9.11.4.31.9, figure 9.11.4.31.10, figure 9.11.4.31.11 and table 9.11.4.31.1.

The Received MBS container is a type 6 information element with a minimum length of 9 octets and a maximum length of 65538 octets.

87654321
Received MBS container IEIoctet 1
Length of Received MBS container contentsoctet 2octet 3
Received MBS information 1octet 4octet e
Received MBS information 2octet (e+1)*octet l*
octet (l+1)*octet m*
Received MBS information poctet (m+1)*octet n*

Figure 9.11.4.31.1: Received MBS container information element

87654321
Rejection causeMSAIMDoctet 4
000IPATMSCIMTIIPAEoctet 5
spare
TMGIoctet 6octet j
Source IP address informationoctet (j+1)*octet v*
Destination IP address informationoctet (v+1)*octet k*
MBS service areaoctet (k+1)*octet s*
MBS timersoctet (s+1)*octet i*
MBS security containeroctet (i+1)*octet e*

Figure 9.11.4.31.2: Received MBS information

87654321
MBS TAI listOctet (k+1)*octet s*

Figure 9.11.4.31.3: MBS service area for MBS service area indication = "MBS service area included as MBS TAI list"

87654321
NR CGI listoctet (k+1)*octet s*

Figure 9.11.4.31.4: MBS service area for MBS service area indication = "MBS service area included as NR CGI list"

87654321
MBS TAI listoctet (k+1)*octet y*
NR CGI listoctet (y+1)*octet s*

Figure 9.11.4.31.5: MBS service area for MBS service area indication = "MBS service area included as MBS TAI list and NR CGI list"

87654321
Length of NR CGI list contentsoctet (k+1)*
NR CGI 1octet (k+2)*octet (k+9)*
NR CGI 2octet (k+10)*octet (k+17)*
octet (k+18)*octet c*
NR CGI woctet (c+1)*octet s*

Figure 9.11.4.31.6: NR CGI list

87654321
NR Cell IDOctet (k+2)*
octet (k+6)*
MCC digit 2MCC digit 1octet (k+7)*
MNC digit 3MCC digit 3octet (k+8)*
MNC digit 2MNC digit 1octet (k+9)*

Figure 9.11.4.31.7: NR CGI

87654321
MBS start timeoctet (s+1)*octet (s+6)*

Figure 9.11.4.31.8: MBS timers for MBS timer indication = "MBS start time"

87654321
MBS back-off timeroctet (s+1)*

Figure 9.11.4.31.9: MBS timers for MBS timer indication = "MBS back-off timer"

87654321
Number of MBS security keys setsOctet (i+1)*
MBS security keys set 1octet (i+2)*octet t*
MBS security keys set 2octet (t+1)*octet g*
octet (g+1)*octet v*
MBS security keys set qoctet (v+1)*octet e*

Figure 9.11.4.31.10: MBS security container

87654321
0spareMTKIOctet (i+2)*
Key domain IDoctet (i+3)*octet (i+5)*
MSK IDoctet (i+6)*octet (i+9)*
MSKoctet (i+10)*octet (i+25)*
MTK IDoctet (i+26)*octet (i+27)*
Encrypted MTKoctet (i+28)*octet (i+43)*

Figure 9.11.4.31.11: MBS security keys set

Table 9.11.4.31.1: Received MBS container information element

MBS decision (MD) (bits 1 to 3 of octet 4)
The MD indicates the network decision of the join requested by the UE, the network requests to remove the UE from the multicast MBS session or the network request to update the MBS service area or the security information of multicast MBS session.
Bits
321
001MBS service area update
010MBS join is accepted
011MBS join is rejected
100Remove UE from multicast MBS session
101MBS security information update
All other values are unused in this version of the specification and interpreted as 000 if received.
If MD is set to "MBS join is rejected" or “Remove UE from multicast MBS session”, bits 6 to 8 of octet 4 shall contain the Rejection cause which indicates the reason of rejecting the MBS join request or the reason of removing the UE from multicast MBS session, respectively, otherwise bits 6 to 8 of octet 4 are spare and shall be coded as zero.
MBS service area indication (MSAI) (bits 4 and 5 of octet 4)
The MSAI indicates whether and how the MBS service area is included in the IE.
Bits
54
00MBS service area not included
01MBS service area included as MBS TAI list
10MBS service area included as NR CGI list
11MBS service area included as MBS TAI list and NR CGI list
Rejection cause (bits 6 to 8 of octet 4)
The Rejection cause indicates the reason of rejecting the join request or the reason of removing the UE from the MBS session.
Bits
876
000No additional information provided
001Insufficient resources
010User is not authorized to use MBS service
011multicast MBS session has not started or will not start soon
100User is outside of local MBS service area
101Session context not found
110multicast MBS session is released
All other values are unused in this version of the specification and interpreted as 000 if received.
IP address existence (IPAE) (bit1 of octet 5)
The IPAE indicates whether the Source IP address information and Destination IP address information are included in the IE or not.
Bit
1
0Source and destination IP address information not included
1Source and destination IP address information included
If IPAE is set to "Source and destination IP address information included", Source IP address information and Destination IP address information shall be included in the IE, otherwise Source IP address information and Destination IP address information shall not be included in the IE (NOTE 1).
MBS timer indication (MTI) (bits 2 and 3 of octet 5)
The MTI indicates whether there is MBS timer included in the IE or not.
Bit
32
00No MBS timers included
01MBS start time included
10MBS back-off timer included
All other values are unused in this version of the specification and interpreted as 00 if received
MBS security container indication (MSCI) (bit 4 of octet 5)
The MSCI indicates whether the MBS security container is included in the IE or not
Bit
4
0MBS security container not included
1MBS security container included
IP address type (IPAT) (bit 5 of octet 5)
The IPAT indicates the type of the source IP address information and destination IP address information. This field is ignored when IPAE is set to "Source and destination IP address information not included".
Bit
5
0Source IP address information and destination IP address information are IPv4
1Source IP address information and destination IP address information are IPv6
Bits 6 to 8 of octet 5 are spare and shall be coded as zero.
TMGI (octets 6 to j)
The TMGI is coded as described in clause 10.5.6.13 in 3GPP TS 24.008 [12] starting from octet 2. The structure of the TMGI is defined in 3GPP TS 23.003 [4].
Source IP address information (octet j+1 to v)
This field contains the IP unicast address used as source address in IP packets for identifying the source of the multicast service. The value of this field is copied from the corresponding source IP address information in the requested MBS container. If the IPAT indicates "Source and destination IP address information are IPv4", the Source IP address information in octet j+1 to octet j+4 contains an IPv4 address. If the IPAT indicates "Source and destination IP address information are IPv6", the Source IP address information in octet j+1 to octet j+16 contains an IPv6 address
Destination IP address information (octet v+1 to k)
This field contains the IP multicast address used as destination address in related IP packets for identifying a multicast service associated with the source. The value of this field is copied from the corresponding destination IP address information in the requested MBS container. If the IPAT indicates "Source and destination IP address information are IPv4", the Destination IP address information in octet v+1 to octet v+4 contains an IPv4 address. If the IPAT indicates "Source and destination IP address information are IPv6", the Destination IP address information in octet v+1 to octet v+16 contains an IPv6 address.
MBS service area (octet k+1 to s)
The MBS service area contains the MBS TAI list, the NR CGI list or both, that identifies the service area(s) for a local MBS service.
MBS TAI list (octet k+1 to s)
The MBS TAI list is coded as octet 2 and above of the 5GS tracking area identity list IE defined in clause 9.11.3.9.
NR CGI (octet k+2 to k+9)
The NR CGI globally identifies an NR cell. It contains the NR Cell ID and the PLMN ID of that cell.
NR Cell ID (octet k+2 to k+6)
The NR Cell ID consists of 36 bits identifying an NR Cell ID as specified in clause 9.3.1.7 of 3GPP TS 38.413 [31], in hexadecimal representation. Bit 8 of octet k+2 is the most significant bit and bit 5 of octet k+6 is the least significant bit. Bits 1 to 4 of octet k+6 are spare and shall be coded as zero.
MCC, Mobile country code (octet k+7 and bits 1 to 4 octet k+8)The MCC field is coded as in ITU-T Recommendation E.212 [42], annex A.
MNC, Mobile network code (bits 5 to 8 of octet k+8 and octet k+9)The coding of this field is the responsibility of each administration but BCD coding shall be used. The MNC shall consist of 2 or 3 digits. If a network operator decides to use only two digits in the MNC, bits 5 to 8 of octet k+8 shall be coded as "1111".
The MCC and MNC digits are coded as octets 6 to 8 of the Temporary mobile group identity IE in figure 10.5.154 of 3GPP TS 24.008 [12].
MBS start time (octets s+1 to s+6)
The MBS start time is coded as described in clause 10.5.3.9 in 3GPP TS 24.008 [12] starting from octet 2 till octet 7.
MBS back-off timer (octet s+1)
The MBS back-off timer is coded as octet 3 described in clause 10.5.7.4a in 3GPP TS 24.008 [12].
MTK indication (MTKI) (bit1 of octet i+2)
The MTKI indicates whether the MTK ID and Encrypted MTK are included in the MBS security keys set or not.
Bit
1
0MTK ID and Encrypted MTK not included
1MTK ID and Encrypted MTK included
Bits 2 to 8 of octet i+2 are spare and shall be coded as zero
Key domain ID (octet i+3 to i+5)The key domain ID is 3 bytes long and is defined in 3GPP TS 33.246 [57] (NOTE 2).
MBS Service Key Identifier (MSK ID) (octets i+6 to i+9)
The MSK ID is 4 bytes long and is defined in 3GPP TS 33.246 [57].
MBS Service Key (MSK) (octets i+10 to i+25)
The MSK is 16 bytes long and is defined in 3GPP TS 33.246 [57].
MBS Traffic Key Identifier (MTK ID) (octets i+26 to i+27)
The MTK ID is 2 bytes long and is defined in 3GPP TS 33.246 [57].
Encrypted MBS Traffic Key (Encrypted MTK) (octets i+28 to i+43)
The Encrypted MTK is 16 bytes long and contains the encrypted version of MTK using MSK as defined in 3GPP TS 33.246 [57].
NOTE 1: The IPAE bit is not expected to be set to "Source and destination IP address information included" when the MBS decision (MD) indicates "Remove UE from multicast MBS session".NOTE 2: As specified in annex W in 3GPP TS 33.501 [24], the UE should not try to use the MCC and MNC constructing the key domain ID in another context, e.g. the UE should not compare those MCC and MNC to parameters received from lower layers.