| Protocol | rrc | Network | 5g |
|---|---|---|---|
| Spec | 3GPP TS 38.331 | Spec Section | 6.2.2 |
| Direction | UE -> gNB | Message Type | Segmented Dedicated Control |
| Full message name | 5G NR - UL Dedicated Message Segment |
|---|---|
| Protocol | RRC |
| Technology | 5G |
| Direction | UE -> gNB |
| Interface | Uu |
| Signaling bearer / channel | SRB1 / SRB2 / UL-DCCH |
| Typical trigger | Used when an uplink dedicated RRC payload is large enough to require segmentation. |
| Main purpose | Lets the UE split a large dedicated RRC payload into multiple uplink segments for successful delivery. |
| Main specification | 3GPP TS 38.331, 6.2.2 |
| Release added | Release 16 |
| Procedures where used | Large Dedicated RRC Uplink Delivery, Segmented Failure or UE Information Reporting |
UL Dedicated Message Segment is the uplink NR RRC segmentation container used when a UE dedicated RRC payload is too large to send as a single message.
Lets the UE split a large dedicated RRC payload into multiple uplink segments for successful delivery.
UL Dedicated Message Segment lets the UE split a large uplink RRC message into smaller pieces.
Call flow position: Used during uplink delivery of a large dedicated RRC payload.
Typical state: UE is in connected mode and sending segmented dedicated content.
Preconditions:
Next likely message: Next segment or completed reassembly at the network
Previous message(s): UE Information Response, Failure Information
Next message(s): Further UL segments, Segment reassembly at the network
Security context: Sent as protected connected-mode signaling.
ULDedicatedMessageSegment ::= SEQUENCE {
segmentNumber INTEGER,
segmentContainer OCTET STRING
}
The outer structure is simple; the main issue is segment continuity and successful reassembly.
UL-DCCH-Message
message: ulDedicatedMessageSegment
segmentNumber: 2
segmentContainer: present
| IE | Required | Description |
|---|---|---|
segmentNumber | Yes | Identifies the current uplink segment sequence. |
segmentContainer | Yes | Carries the uplink dedicated RRC fragment. |
segmentNumberIdentifies the current uplink segment sequence.
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.
segmentContainerCarries the uplink dedicated RRC fragment.
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: One or more uplink segments may be missing.
What to inspect: Check segment numbering and whether the last fragment arrived.
Next step: Compare segmentation behavior with lower-layer delivery and later network response.
It is used when a UE's dedicated RRC payload is too large to send as one message.
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.