RLC-BearerConfig

RRC IE · TS 38.331 v19.4.0 (2026-09) · clause 6.3.2

RLC-BearerConfig is an RRC information element of 3GPP TS 38.331 (38331), the 5G NR Radio Resource Control (RRC) protocol.

First seen v15.2.0 (2018-06) · Last changed v19.0.0 (2025-10)

Definition

The IE RLC-BearerConfig is used to configure an RLC entity, a corresponding logical channel in MAC and the linking to a PDCP entity (served radio bearer).

RLC-BearerConfig ::=                        SEQUENCE {
    logicalChannelIdentity                      LogicalChannelIdentity,
    servedRadioBearer                           CHOICE {
        srb-Identity                                SRB-Identity,
        drb-Identity                                DRB-Identity
    }                                                                                               OPTIONAL,   -- Cond LCH-SetupOnly
    reestablishRLC                              ENUMERATED {true}                                   OPTIONAL,   -- Need N
    rlc-Config                                  RLC-Config                                          OPTIONAL,   -- Cond LCH-Setup
    mac-LogicalChannelConfig                    LogicalChannelConfig                                OPTIONAL,   -- Cond LCH-Setup
    ...,
    [[
        rlc-Config-v1610                            RLC-Config-v1610                                    OPTIONAL    -- Need R
    ]],
    [[
        rlc-Config-v1700                            RLC-Config-v1700                                    OPTIONAL,   -- Need R
        logicalChannelIdentityExt-r17               LogicalChannelIdentityExt-r17                       OPTIONAL,   -- Cond LCH-SetupModMRB
        multicastRLC-BearerConfig-r17               MulticastRLC-BearerConfig-r17                       OPTIONAL,   -- Cond LCH-SetupOnlyMRB
        servedRadioBearerSRB4-r17                   SRB-Identity-v1700                                  OPTIONAL    -- Cond LCH-SetupOnlySRB4
    ]],
    [[
        servedRadioBearerSRB5-r18                   SRB-Identity-v1800                                  OPTIONAL    -- Cond LCH-SetupOnlySRB5
    ]],
    [[
        rlc-Config-v1900                            RLC-Config-v1900                                    OPTIONAL,   -- Need R
        servedRadioBearerSRB6-r19                   SRB-Identity-v1900                                  OPTIONAL  -- Cond LCH-SetupOnlySRB6
    ]]
}

Fields (15)

Field	Description
logicalChannelIdentity LogicalChannelIdentity	ID used commonly for the MAC logical channel and for the RLC bearer.
servedRadioBearer CHOICE { · OPTIONAL Cond LCH-SetupOnly	Associates the RLC Bearer with an SRB or a DRB. The UE shall deliver DL RLC SDUs received via the RLC entity of this RLC bearer to the PDCP entity of the servedRadioBearer . Furthermore, the UE shall advertise and deliver uplink PDCP PDUs of the uplink PDCP entity of the servedRadioBearer to the uplink RLC entity of this RLC bearer unless the uplink scheduling restrictions ( moreThanOneRLC in PDCP-Config and the restrictions in LogicalChannelConfig ) forbid it to do so.
srb-Identity SRB-Identity
drb-Identity DRB-Identity
reestablishRLC ENUMERATED {true} · OPTIONAL Need N	Indicates that RLC should be re-established. Network sets this to true at least whenever the security key used for the radio bearer associated with this RLC entity changes. For SRB2, multicast MRBs and DRBs, unless full configuration is used, it is also set to true during the resumption of the RRC connection or the first reconfiguration after reestablishment. For SRB1, when resuming an RRC connection, or at the first reconfiguration after RRC connection reestablishment, the network does not set this field to true. The network does not include this field if servedRadioBearer is set to drb-Identity and the RLC-BearerConfig IE is part of an RRCReconfiguration message within the LTM-Config IE. For DRBs, network doesn't include this field if the RLC-BearerConfig IE is part of an RRCReconfiguration message associated with subsequent CPAC within the ConditionalReconfiguration IE. Network doesn't include this field if the RadioBearerConfig IE is part of an RRCReconfiguration message associated with subsequent CPAC within the ConditionalReconfiguration IE which is received within a MCG RRCReconfiguration message via SRB1.
rlc-Config RLC-Config · OPTIONAL Cond LCH-Setup	Determines the RLC mode (UM, AM) and provides corresponding parameters. RLC mode reconfiguration can only be performed by DRB/multicast MRB release/addition or full configuration. The network may configure rlc-Config-v1610 only when rlc-Config (without suffix) is set to am .
mac-LogicalChannelConfig LogicalChannelConfig · OPTIONAL Cond LCH-Setup
rlc-Config-v1610 RLC-Config-v1610 · OPTIONAL Need R since v16.1.0	Determines the RLC mode (UM, AM) and provides corresponding parameters. RLC mode reconfiguration can only be performed by DRB/multicast MRB release/addition or full configuration. The network may configure rlc-Config-v1610 only when rlc-Config (without suffix) is set to am .
rlc-Config-v1700 RLC-Config-v1700 · OPTIONAL Need R since v17.0.0	Determines the RLC mode (UM, AM) and provides corresponding parameters. RLC mode reconfiguration can only be performed by DRB/multicast MRB release/addition or full configuration. The network may configure rlc-Config-v1610 only when rlc-Config (without suffix) is set to am .
logicalChannelIdentityExt-r17 LogicalChannelIdentityExt-r17 · OPTIONAL Cond LCH-SetupModMRB since v17.0.0	Extended logical channel ID used commonly for the MAC logical channel and for the RLC bearer for PTM reception. If this field is configured, the UE shall ignore logicalChannelIdentity .
multicastRLC-BearerConfig-r17 MulticastRLC-BearerConfig-r17 · OPTIONAL Cond LCH-SetupOnlyMRB since v17.0.0
servedRadioBearerSRB4-r17 SRB-Identity-v1700 · OPTIONAL Cond LCH-SetupOnlySRB4 since v17.0.0	Associates the RLC Bearer with an SRB or a DRB. The UE shall deliver DL RLC SDUs received via the RLC entity of this RLC bearer to the PDCP entity of the servedRadioBearer . Furthermore, the UE shall advertise and deliver uplink PDCP PDUs of the uplink PDCP entity of the servedRadioBearer to the uplink RLC entity of this RLC bearer unless the uplink scheduling restrictions ( moreThanOneRLC in PDCP-Config and the restrictions in LogicalChannelConfig ) forbid it to do so.
servedRadioBearerSRB5-r18 SRB-Identity-v1800 · OPTIONAL Cond LCH-SetupOnlySRB5 since v18.5.0	Associates the RLC Bearer with an SRB or a DRB. The UE shall deliver DL RLC SDUs received via the RLC entity of this RLC bearer to the PDCP entity of the servedRadioBearer . Furthermore, the UE shall advertise and deliver uplink PDCP PDUs of the uplink PDCP entity of the servedRadioBearer to the uplink RLC entity of this RLC bearer unless the uplink scheduling restrictions ( moreThanOneRLC in PDCP-Config and the restrictions in LogicalChannelConfig ) forbid it to do so.
rlc-Config-v1900 RLC-Config-v1900 · OPTIONAL Need R since v19.0.0	Determines the RLC mode (UM, AM) and provides corresponding parameters. RLC mode reconfiguration can only be performed by DRB/multicast MRB release/addition or full configuration. The network may configure rlc-Config-v1610 only when rlc-Config (without suffix) is set to am .
servedRadioBearerSRB6-r19 SRB-Identity-v1900 · OPTIONAL Cond LCH-SetupOnlySRB6 since v19.0.0	Associates the RLC Bearer with an SRB or a DRB. The UE shall deliver DL RLC SDUs received via the RLC entity of this RLC bearer to the PDCP entity of the servedRadioBearer . Furthermore, the UE shall advertise and deliver uplink PDCP PDUs of the uplink PDCP entity of the servedRadioBearer to the uplink RLC entity of this RLC bearer unless the uplink scheduling restrictions ( moreThanOneRLC in PDCP-Config and the restrictions in LogicalChannelConfig ) forbid it to do so.

Used by (1)

CellGroupConfig

RLC-BearerConfig

Definition

Fields (15)

Used by (1)

Uses (13)

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