| Protocol | rrc | Network | 5g |
|---|---|---|---|
| Spec | 3GPP TS 38.331 | Spec Section | 6.2.2 |
| Direction | gNB -> UE | Message Type | MBS Configuration |
| Full message name | 5G NR - MBS Broadcast Configuration |
|---|---|
| Protocol | RRC |
| Technology | 5G |
| Direction | gNB -> UE |
| Interface | Uu |
| Signaling bearer / channel | SRB1 / DL-DCCH |
| Typical trigger | Used when the network needs to deliver dedicated MBS broadcast configuration to the UE. |
| Main purpose | Carries dedicated MBS broadcast configuration so the UE can receive or continue receiving the intended MBS broadcast service. |
| Main specification | 3GPP TS 38.331, 6.2.2 |
| Release added | Release 17 |
| Procedures where used | MBS Broadcast Service Configuration |
MBS Broadcast Configuration is the NR RRC message used to provide UE-specific or dedicated MBS broadcast configuration.
Carries dedicated MBS broadcast configuration so the UE can receive or continue receiving the intended MBS broadcast service.
MBS Broadcast Configuration delivers dedicated broadcast-service settings to the UE.
Call flow position: Sent when dedicated MBS broadcast configuration must be delivered.
Typical state: UE is in connected mode with MBS context.
Preconditions:
Next likely message: UE applies the broadcast configuration
Previous message(s): RRC Reconfiguration
Next message(s): MBS broadcast reception handling
Security context: Sent as protected connected-mode signaling.
MBSBroadcastConfiguration ::= SEQUENCE {
mbsBroadcastConfig OCTET STRING
}
The inner MBS broadcast configuration matters more than the wrapper itself.
DL-DCCH-Message
message: mbsBroadcastConfiguration
mbsBroadcastConfig: present
| IE | Required | Description |
|---|---|---|
mbsBroadcastConfig | Yes | Carries the MBS broadcast configuration relevant to the UE. |
mbsBroadcastConfigCarries the MBS broadcast configuration relevant to the UE.
Presence: Required
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
Likely cause: The MBS broadcast configuration may be missing or not applied.
What to inspect: Check the dedicated configuration and the later service behavior.
Next step: Compare it with SIB20 and other MBS-related context.
It provides dedicated MBS broadcast configuration to the UE.
Decode this message with the 3GPP Decoder, inspect the related message database, or open the matching call flow to see where this signaling step fits in the full procedure.